/* ========================================================================
   MillilitersIntoMilligrams — Premium Volume-to-Mass Converter
   Design System: Dark Luxury · Glassmorphism · Teal-to-Violet Gradient
   ======================================================================== */

/* --- CSS Custom Properties --- */
:root {
    /* Brand Gradient — Teal to Violet */
    --grad-start: #06b6d4;
    --grad-mid: #6366f1;
    --grad-end: #8b5cf6;
    --accent-1: #06b6d4;
    --accent-2: #6366f1;
    --accent-3: #8b5cf6;

    /* Surfaces */
    --bg-body: #06080c;
    --bg-surface: rgba(10, 14, 22, 0.65);
    --bg-card: rgba(12, 16, 26, 0.55);
    --bg-card-hover: rgba(16, 22, 38, 0.7);
    --bg-input: rgba(8, 12, 20, 0.8);
    --border-subtle: rgba(6, 182, 212, 0.1);
    --border-glow: rgba(6, 182, 212, 0.25);

    /* Text */
    --text-primary: #e8ecf5;
    --text-secondary: #8094b0;
    --text-tertiary: #4f6580;
    --text-accent: #06b6d4;

    /* Layout */
    --container-max: 1200px;
    --section-gap: 120px;
    --radius-sm: 10px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --radius-xl: 32px;

    /* Typography */
    --font-display: 'Space Grotesk', sans-serif;
    --font-body: 'Inter', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;

    /* Transitions */
    --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
    --transition-fast: 0.2s var(--ease-out-expo);
    --transition-med: 0.4s var(--ease-out-expo);
    --transition-slow: 0.7s var(--ease-out-expo);
}

/* --- Reset & Base --- */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-body);
    background: var(--bg-body);
    color: var(--text-primary);
    line-height: 1.7;
    overflow-x: hidden;
    position: relative;
}

::selection {
    background: rgba(6, 182, 212, 0.25);
    color: #fff;
}

a {
    color: var(--text-accent);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--accent-3);
}

img {
    max-width: 100%;
    display: block;
}

/* --- Ambient Background --- */
.ambient-bg {
    position: fixed;
    inset: 0;
    z-index: -1;
    overflow: hidden;
    pointer-events: none;
}

.orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(120px);
    opacity: 0.3;
    animation: orbFloat 20s ease-in-out infinite;
}

.orb-1 {
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, var(--accent-1), transparent 70%);
    top: -10%;
    left: -8%;
    animation-duration: 22s;
}

.orb-2 {
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, var(--accent-2), transparent 70%);
    bottom: 10%;
    right: -5%;
    animation-duration: 26s;
    animation-delay: -8s;
}

.orb-3 {
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, var(--accent-3), transparent 70%);
    top: 50%;
    left: 40%;
    animation-duration: 30s;
    animation-delay: -14s;
}

@keyframes orbFloat {

    0%,
    100% {
        transform: translate(0, 0) scale(1);
    }

    25% {
        transform: translate(60px, -40px) scale(1.08);
    }

    50% {
        transform: translate(-30px, 50px) scale(0.95);
    }

    75% {
        transform: translate(-50px, -30px) scale(1.05);
    }
}

.grid-overlay {
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(6, 182, 212, 0.02) 1px, transparent 1px),
        linear-gradient(90deg, rgba(6, 182, 212, 0.02) 1px, transparent 1px);
    background-size: 60px 60px;
    mask-image: radial-gradient(ellipse 70% 60% at 50% 50%, black, transparent);
}

/* --- Navigation --- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 16px 0;
    transition: background var(--transition-med), box-shadow var(--transition-med), padding var(--transition-med);
}

.navbar.scrolled {
    background: rgba(6, 8, 12, 0.88);
    backdrop-filter: blur(20px) saturate(1.4);
    -webkit-backdrop-filter: blur(20px) saturate(1.4);
    box-shadow: 0 1px 0 var(--border-subtle), 0 8px 32px rgba(0, 0, 0, 0.5);
    padding: 10px 0;
}

.nav-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 32px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--text-primary);
}

.logo-icon {
    width: 40px;
    height: 40px;
    flex-shrink: 0;
}

.logo-icon svg {
    width: 100%;
    height: 100%;
}

.logo-text {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.25rem;
    letter-spacing: -0.02em;
}

.logo-accent {
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-link {
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-weight: 500;
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    text-decoration: none;
}

.nav-link:hover {
    color: var(--text-primary);
    background: rgba(6, 182, 212, 0.08);
}

.nav-cta {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 22px;
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
    color: #06080c;
    font-weight: 600;
    font-size: 0.875rem;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-family: var(--font-body);
}

.nav-cta:hover {
    transform: translateY(-1px);
    box-shadow: 0 8px 24px rgba(6, 182, 212, 0.3);
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all var(--transition-fast);
}

/* --- Gradient Text --- */
.gradient-text {
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2), var(--accent-3));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* --- Hero Section --- */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 120px 0 80px;
    position: relative;
}

.hero-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 32px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: center;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    background: rgba(6, 182, 212, 0.08);
    border: 1px solid rgba(6, 182, 212, 0.15);
    color: var(--accent-1);
    padding: 8px 20px;
    border-radius: 100px;
    font-size: 0.8rem;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    margin-bottom: 24px;
    animation: fadeInUp 0.8s var(--ease-out-expo) both;
}

.badge-dot {
    width: 8px;
    height: 8px;
    background: var(--accent-1);
    border-radius: 50%;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {

    0%,
    100% {
        opacity: 1;
        transform: scale(1);
    }

    50% {
        opacity: 0.5;
        transform: scale(0.8);
    }
}

.hero-title {
    font-family: var(--font-display);
    font-size: clamp(2.8rem, 5.5vw, 4.5rem);
    font-weight: 800;
    line-height: 1.08;
    letter-spacing: -0.03em;
    margin-bottom: 24px;
    animation: fadeInUp 0.8s 0.1s var(--ease-out-expo) both;
}

.hero-description {
    font-size: 1.1rem;
    line-height: 1.75;
    color: var(--text-secondary);
    max-width: 520px;
    margin-bottom: 36px;
    animation: fadeInUp 0.8s 0.2s var(--ease-out-expo) both;
}

.hero-actions {
    display: flex;
    gap: 16px;
    margin-bottom: 48px;
    animation: fadeInUp 0.8s 0.3s var(--ease-out-expo) both;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 32px;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 0.95rem;
    font-family: var(--font-body);
    cursor: pointer;
    transition: all var(--transition-fast);
    border: none;
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
    color: #06080c;
    box-shadow: 0 4px 16px rgba(6, 182, 212, 0.25);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 32px rgba(6, 182, 212, 0.4);
    color: #06080c;
}

.btn-secondary {
    background: rgba(6, 182, 212, 0.08);
    color: var(--text-primary);
    border: 1px solid rgba(6, 182, 212, 0.2);
}

.btn-secondary:hover {
    background: rgba(6, 182, 212, 0.14);
    border-color: rgba(6, 182, 212, 0.35);
    color: var(--text-primary);
}

.hero-stats {
    display: flex;
    align-items: center;
    gap: 32px;
    animation: fadeInUp 0.8s 0.4s var(--ease-out-expo) both;
}

.hero-stat {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.stat-number {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-weight: 500;
}

.hero-stat-divider {
    width: 1px;
    height: 40px;
    background: linear-gradient(to bottom, transparent, var(--border-glow), transparent);
}

.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
    animation: fadeInUp 0.8s 0.3s var(--ease-out-expo) both;
}

.hero-equation-container {
    position: relative;
    width: 500px;
    height: 500px;
}

.hero-equation-container canvas {
    width: 100%;
    height: 100%;
}

.equation-glow {
    position: absolute;
    inset: 0;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(6, 182, 212, 0.1), transparent 60%);
    pointer-events: none;
}

.hero-scroll-indicator {
    display: flex;
    align-items: center;
    gap: 8px;
    justify-content: center;
    margin-top: 32px;
    color: var(--text-tertiary);
    font-size: 0.8rem;
    animation: fadeInUp 1s 0.6s var(--ease-out-expo) both;
}

.scroll-arrow {
    animation: scrollBounce 2s ease-in-out infinite;
}

@keyframes scrollBounce {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(6px);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(24px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* --- Section Common --- */
.section-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 32px;
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-tag {
    display: inline-block;
    background: rgba(6, 182, 212, 0.08);
    border: 1px solid rgba(6, 182, 212, 0.15);
    color: var(--accent-1);
    padding: 6px 18px;
    border-radius: 100px;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    margin-bottom: 20px;
}

.section-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 4vw, 2.8rem);
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: -0.02em;
    margin-bottom: 16px;
}

.section-subtitle {
    color: var(--text-secondary);
    font-size: 1.05rem;
    max-width: 640px;
    margin: 0 auto;
    line-height: 1.7;
}

/* --- How It Works --- */
.how-it-works {
    padding: var(--section-gap) 0;
}

.steps-grid {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
}

.step-card {
    flex: 1;
    max-width: 300px;
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: 36px 28px;
    text-align: center;
    position: relative;
    backdrop-filter: blur(12px);
    transition: all var(--transition-med);
}

.step-card::before {
    content: attr(data-step);
    position: absolute;
    top: -14px;
    left: 50%;
    transform: translateX(-50%);
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
    color: #06080c;
    font-family: var(--font-mono);
    font-weight: 700;
    font-size: 0.75rem;
    padding: 4px 14px;
    border-radius: 100px;
}

.step-card:hover {
    border-color: var(--border-glow);
    background: var(--bg-card-hover);
    transform: translateY(-4px);
    box-shadow: 0 16px 48px rgba(6, 182, 212, 0.08);
}

.step-icon {
    width: 56px;
    height: 56px;
    margin: 0 auto 20px;
    color: var(--accent-1);
}

.step-icon svg {
    width: 100%;
    height: 100%;
}

.step-title {
    font-family: var(--font-display);
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 10px;
}

.step-desc {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
}

.step-connector {
    width: 80px;
    flex-shrink: 0;
}

.step-connector svg {
    width: 100%;
    height: auto;
}

/* --- Calculator Section --- */
.calculator-section {
    padding: var(--section-gap) 0;
}

.calculator-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
}

.calc-card {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: 32px;
    backdrop-filter: blur(12px);
}

.calc-card-title {
    display: flex;
    align-items: center;
    gap: 10px;
    font-family: var(--font-display);
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 28px;
    color: var(--text-primary);
}

.calc-card-title svg {
    color: var(--accent-1);
    flex-shrink: 0;
}

/* --- Converter Form --- */
.converter-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.form-label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.form-input-wrap {
    position: relative;
}

.form-input {
    width: 100%;
    padding: 14px 18px;
    background: var(--bg-input);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 1.1rem;
    font-family: var(--font-mono);
    font-weight: 500;
    transition: all var(--transition-fast);
    outline: none;
}

.form-input:focus {
    border-color: var(--accent-1);
    box-shadow: 0 0 0 3px rgba(6, 182, 212, 0.12);
}

.form-input::placeholder {
    color: var(--text-tertiary);
    font-family: var(--font-body);
}

.form-unit {
    position: absolute;
    right: 14px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--accent-1);
    font-family: var(--font-mono);
    font-weight: 600;
    font-size: 0.85rem;
    pointer-events: none;
    background: var(--bg-input);
    padding-left: 8px;
}

.form-select {
    width: 100%;
    padding: 14px 18px;
    background: var(--bg-input);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 0.95rem;
    font-family: var(--font-body);
    cursor: pointer;
    outline: none;
    transition: all var(--transition-fast);
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg width='12' height='8' viewBox='0 0 12 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1.5L6 6.5L11 1.5' stroke='%238094b0' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 16px center;
    padding-right: 40px;
}

.form-select:focus {
    border-color: var(--accent-1);
    box-shadow: 0 0 0 3px rgba(6, 182, 212, 0.12);
}

.form-select option {
    background: #0c1018;
    color: var(--text-primary);
}

/* --- Result Display --- */
.result-container {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: 32px;
    backdrop-filter: blur(12px);
    height: 100%;
    display: flex;
    flex-direction: column;
}

.result-display {
    text-align: center;
    padding: 24px 0;
}

.result-big {
    font-family: var(--font-display);
    font-size: clamp(2.2rem, 4vw, 3rem);
    font-weight: 800;
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2), var(--accent-3));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
    word-break: break-all;
}

.result-label-text {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.result-divider {
    height: 1px;
    background: linear-gradient(to right, transparent, var(--border-glow), transparent);
    margin: 16px 0;
}

.result-formula-card {
    background: rgba(6, 182, 212, 0.04);
    border: 1px solid rgba(6, 182, 212, 0.1);
    border-radius: var(--radius-md);
    padding: 20px;
    margin-bottom: 16px;
}

.result-formula-card h4 {
    font-family: var(--font-display);
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--accent-1);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-bottom: 12px;
}

.formula-line {
    font-family: var(--font-mono);
    font-size: 0.9rem;
    color: var(--text-secondary);
    padding: 4px 0;
    line-height: 1.6;
}

.formula-line strong {
    color: var(--text-primary);
    font-weight: 600;
}

.result-extras {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-top: auto;
}

.result-extra-item {
    background: rgba(6, 182, 212, 0.04);
    border: 1px solid rgba(6, 182, 212, 0.08);
    border-radius: var(--radius-sm);
    padding: 14px;
}

.extra-label {
    font-size: 0.72rem;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    font-weight: 600;
    margin-bottom: 4px;
}

.extra-value {
    font-family: var(--font-mono);
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95rem;
}

/* --- Diagram Section --- */
.diagram-section {
    padding: var(--section-gap) 0;
}

.diagram-wrapper {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-xl);
    overflow: hidden;
    backdrop-filter: blur(12px);
}

.diagram-tabs {
    display: flex;
    border-bottom: 1px solid var(--border-subtle);
    padding: 8px 8px 0;
    gap: 4px;
}

.diagram-tab {
    padding: 12px 24px;
    background: none;
    border: none;
    color: var(--text-tertiary);
    font-family: var(--font-body);
    font-weight: 600;
    font-size: 0.875rem;
    cursor: pointer;
    border-radius: var(--radius-sm) var(--radius-sm) 0 0;
    transition: all var(--transition-fast);
    position: relative;
}

.diagram-tab:hover {
    color: var(--text-secondary);
}

.diagram-tab.active {
    color: var(--accent-1);
    background: rgba(6, 182, 212, 0.06);
}

.diagram-tab.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(to right, var(--accent-1), var(--accent-2));
}

.diagram-canvas-wrap {
    padding: 32px;
    display: flex;
    justify-content: center;
    min-height: 420px;
}

.diagram-canvas-wrap canvas {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-md);
}

.diagram-explanation {
    padding: 0 32px 32px;
}

.diagram-explanation p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
    text-align: center;
    max-width: 700px;
    margin: 0 auto;
}

.diagram-explanation strong {
    color: var(--text-primary);
}

/* --- Conversion Table --- */
.table-section {
    padding: var(--section-gap) 0;
}

.table-wrap {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    overflow: hidden;
    backdrop-filter: blur(12px);
}

.table-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 24px 28px;
    border-bottom: 1px solid var(--border-subtle);
    flex-wrap: wrap;
    gap: 16px;
}

.table-header h3 {
    font-family: var(--font-display);
    font-size: 1.1rem;
    font-weight: 700;
}

.table-controls {
    display: flex;
    align-items: center;
    gap: 12px;
}

.table-voltage-select {
    padding: 10px 36px 10px 16px;
    background: var(--bg-input);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
    color: var(--accent-1);
    font-size: 0.85rem;
    font-family: var(--font-mono);
    font-weight: 600;
    outline: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg width='12' height='8' viewBox='0 0 12 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1.5L6 6.5L11 1.5' stroke='%238094b0' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
}

.table-voltage-select:focus {
    border-color: var(--accent-1);
    box-shadow: 0 0 0 3px rgba(6, 182, 212, 0.12);
}

.table-voltage-select option {
    background: #0c1018;
    color: var(--text-primary);
}

.table-search {
    padding: 10px 16px;
    background: var(--bg-input);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 0.85rem;
    font-family: var(--font-body);
    outline: none;
    width: 200px;
    transition: all var(--transition-fast);
}

.table-search:focus {
    border-color: var(--accent-1);
    box-shadow: 0 0 0 3px rgba(6, 182, 212, 0.12);
}

.table-search::placeholder {
    color: var(--text-tertiary);
}

.conversion-table {
    width: 100%;
    border-collapse: collapse;
}

.conversion-table thead th {
    padding: 14px 20px;
    text-align: left;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--text-tertiary);
    border-bottom: 1px solid var(--border-subtle);
    background: rgba(6, 182, 212, 0.03);
}

.conversion-table tbody td {
    padding: 14px 20px;
    font-size: 0.9rem;
    border-bottom: 1px solid rgba(6, 182, 212, 0.04);
    transition: background var(--transition-fast);
}

.conversion-table tbody tr:hover td {
    background: rgba(6, 182, 212, 0.04);
}

.conversion-table tbody tr {
    cursor: pointer;
}

.conversion-table .mono {
    font-family: var(--font-mono);
    font-weight: 500;
    color: var(--accent-1);
}

/* --- Features --- */
.features {
    padding: var(--section-gap) 0;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.feature-card {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: 32px 28px;
    transition: all var(--transition-med);
    position: relative;
    overflow: hidden;
}

.feature-card::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(to right, var(--accent-1), var(--accent-2));
    opacity: 0;
    transition: opacity var(--transition-med);
}

.feature-card:hover {
    border-color: var(--border-glow);
    background: var(--bg-card-hover);
    transform: translateY(-4px);
    box-shadow: 0 16px 48px rgba(6, 182, 212, 0.06);
}

.feature-card:hover::after {
    opacity: 1;
}

.feature-icon {
    width: 52px;
    height: 52px;
    margin-bottom: 20px;
    color: var(--accent-1);
}

.feature-icon svg {
    width: 100%;
    height: 100%;
}

.feature-card h3 {
    font-family: var(--font-display);
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 10px;
}

.feature-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
}

/* --- FAQ --- */
.faq-section {
    padding: var(--section-gap) 0;
}

.faq-grid {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.faq-item {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: all var(--transition-fast);
}

.faq-item:hover {
    border-color: var(--border-glow);
}

.faq-question {
    width: 100%;
    text-align: left;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 20px 24px;
    background: none;
    border: none;
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
}

.faq-chevron {
    flex-shrink: 0;
    color: var(--text-tertiary);
    transition: transform var(--transition-fast);
}

.faq-item.open .faq-chevron {
    transform: rotate(180deg);
    color: var(--accent-1);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-med), padding var(--transition-med);
}

.faq-item.open .faq-answer {
    max-height: 500px;
}

.faq-answer p {
    padding: 0 24px 20px;
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
}

/* --- Footer --- */
.footer {
    border-top: 1px solid var(--border-subtle);
    padding: 64px 0 0;
}

.footer-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 32px;
}

.footer-top {
    display: grid;
    grid-template-columns: 1.4fr repeat(4, 1fr);
    gap: 36px;
    padding-bottom: 48px;
}

.footer-brand .nav-logo {
    margin-bottom: 16px;
}

.footer-tagline {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
    max-width: 300px;
}

.footer-links-group h4 {
    font-family: var(--font-display);
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.footer-links-group a {
    display: block;
    color: var(--text-secondary);
    font-size: 0.88rem;
    padding: 4px 0;
    transition: color var(--transition-fast);
}

.footer-links-group a:hover {
    color: var(--accent-1);
}

.footer-bottom {
    border-top: 1px solid var(--border-subtle);
    padding: 24px 0;
    text-align: center;
}

.footer-bottom p {
    color: var(--text-tertiary);
    font-size: 0.8rem;
}

/* --- Back to Top --- */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 48px;
    height: 48px;
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-1);
    cursor: pointer;
    z-index: 900;
    opacity: 0;
    visibility: hidden;
    transform: translateY(12px);
    transition: all var(--transition-fast);
    backdrop-filter: blur(12px);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: rgba(6, 182, 212, 0.1);
    border-color: var(--border-glow);
    transform: translateY(-2px);
}

/* --- Live Indicator --- */
.live-indicator {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.72rem;
    font-weight: 600;
    color: var(--accent-2);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 8px;
}

.live-dot {
    width: 6px;
    height: 6px;
    background: var(--accent-2);
    border-radius: 50%;
    animation: pulse 1.5s ease-in-out infinite;
}

/* --- Responsive --- */
@media (max-width: 1024px) {
    .hero-container {
        grid-template-columns: 1fr;
        gap: 40px;
        text-align: center;
    }

    .hero-description {
        margin: 0 auto 36px;
    }

    .hero-actions {
        justify-content: center;
    }

    .hero-stats {
        justify-content: center;
    }

    .hero-visual {
        order: -1;
    }

    .hero-equation-container {
        width: 350px;
        height: 350px;
    }

    .calculator-layout {
        grid-template-columns: 1fr;
    }

    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .footer-top {
        grid-template-columns: 1fr 1fr;
        gap: 32px;
    }
}

@media (max-width: 768px) {
    :root {
        --section-gap: 80px;
    }

    .nav-links {
        display: none;
    }

    .nav-cta {
        display: none;
    }

    .mobile-menu-btn {
        display: flex;
    }

    .mobile-menu-btn.open span:nth-child(1) {
        transform: rotate(45deg) translateY(7px);
    }

    .mobile-menu-btn.open span:nth-child(2) {
        opacity: 0;
    }

    .mobile-menu-btn.open span:nth-child(3) {
        transform: rotate(-45deg) translateY(-7px);
    }

    .nav-links.open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: rgba(6, 8, 12, 0.95);
        backdrop-filter: blur(20px);
        padding: 16px 24px;
        border-bottom: 1px solid var(--border-subtle);
        gap: 4px;
    }

    .hero {
        min-height: auto;
        padding: 100px 0 60px;
    }

    .hero-title {
        font-size: 2.4rem;
    }

    .hero-equation-container {
        width: 280px;
        height: 280px;
    }

    .steps-grid {
        flex-direction: column;
    }

    .step-connector {
        transform: rotate(90deg);
        width: 40px;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }

    .footer-top {
        grid-template-columns: 1fr;
    }

    .table-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .table-controls {
        width: 100%;
    }

    .table-search {
        flex: 1;
        width: auto;
    }
}

@media (max-width: 480px) {
    .hero-actions {
        flex-direction: column;
        align-items: stretch;
    }

    .hero-stats {
        flex-direction: column;
        gap: 16px;
    }

    .hero-stat-divider {
        width: 40px;
        height: 1px;
    }

    .result-extras {
        grid-template-columns: 1fr;
    }

    .diagram-tabs {
        overflow-x: auto;
        flex-wrap: nowrap;
    }

    .diagram-tab {
        white-space: nowrap;
        font-size: 0.8rem;
        padding: 10px 16px;
    }

    .table-controls {
        flex-direction: column;
    }

    .table-search {
        width: 100%;
    }
}

/* ========================================================================
   Content Sections — SEO Informational Blocks with Visual Diagrams
   ======================================================================== */

/* --- Shared Content Section --- */
.content-section {
    padding: var(--section-gap) 0;
}

.content-section .section-subtitle {
    text-align: center;
}

.content-body {
    max-width: 860px;
    margin: 0 auto;
}

.content-body p {
    color: var(--text-secondary);
    font-size: 1rem;
    line-height: 1.8;
    margin-bottom: 20px;
}

.content-body p:last-child {
    margin-bottom: 0;
}

.content-body strong {
    color: var(--text-primary);
    font-weight: 600;
}

/* --- Flow Diagram (How It Works, Convert Steps) --- */
.flow-diagram {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0;
    margin: 48px auto;
    max-width: 820px;
    flex-wrap: wrap;
}

.flow-node {
    flex: 1;
    min-width: 200px;
    max-width: 250px;
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: 28px 24px;
    text-align: center;
    position: relative;
    backdrop-filter: blur(12px);
    transition: all var(--transition-med);
}

.flow-node:hover {
    border-color: var(--border-glow);
    background: var(--bg-card-hover);
    transform: translateY(-4px);
    box-shadow: 0 16px 48px rgba(6, 182, 212, 0.08);
}

.flow-node-icon {
    width: 52px;
    height: 52px;
    margin: 0 auto 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(6, 182, 212, 0.08);
    border: 1px solid rgba(6, 182, 212, 0.15);
    border-radius: 14px;
    color: var(--accent-1);
}

.flow-node-icon svg {
    width: 26px;
    height: 26px;
}

.flow-node-step {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
    color: #06080c;
    font-family: var(--font-mono);
    font-weight: 700;
    font-size: 0.7rem;
    padding: 3px 12px;
    border-radius: 100px;
    letter-spacing: 0.04em;
}

.flow-node h3 {
    font-family: var(--font-display);
    font-size: 1.05rem;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.flow-node p {
    color: var(--text-secondary);
    font-size: 0.88rem;
    line-height: 1.55;
    margin: 0;
}

.flow-arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    flex-shrink: 0;
    color: var(--accent-1);
    opacity: 0.5;
}

.flow-arrow svg {
    width: 28px;
    height: 28px;
}

/* --- Formula Visual --- */
.formula-visual {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-xl);
    padding: 40px;
    margin: 48px auto;
    max-width: 720px;
    backdrop-filter: blur(12px);
    text-align: center;
}

.formula-main {
    font-family: var(--font-mono);
    font-size: clamp(1.3rem, 3vw, 1.8rem);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 24px;
    padding: 20px;
    background: rgba(6, 182, 212, 0.04);
    border: 1px solid rgba(6, 182, 212, 0.1);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    flex-wrap: wrap;
}

.formula-part {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.formula-part-value {
    color: var(--text-primary);
}

.formula-part-label {
    font-size: 0.65rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    padding: 2px 8px;
    border-radius: 4px;
    font-family: var(--font-body);
}

.formula-part-label.label-result {
    background: rgba(139, 92, 246, 0.15);
    color: var(--accent-3);
}

.formula-part-label.label-volume {
    background: rgba(6, 182, 212, 0.15);
    color: var(--accent-1);
}

.formula-part-label.label-density {
    background: rgba(99, 102, 241, 0.15);
    color: var(--accent-2);
}

.formula-part-label.label-factor {
    background: rgba(6, 182, 212, 0.08);
    color: var(--text-tertiary);
}

.formula-operator {
    font-size: 1.3rem;
    color: var(--text-tertiary);
    padding: 0 4px;
}

.formula-examples {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-top: 24px;
}

.formula-example {
    background: rgba(6, 182, 212, 0.04);
    border: 1px solid rgba(6, 182, 212, 0.08);
    border-radius: var(--radius-md);
    padding: 20px;
    text-align: left;
}

.formula-example h4 {
    font-family: var(--font-display);
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--accent-1);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-bottom: 12px;
}

.formula-example .formula-line {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--text-secondary);
    padding: 3px 0;
    line-height: 1.6;
}

.formula-example .formula-line strong {
    color: var(--text-primary);
}

/* --- Chart Section --- */
.chart-visual {
    margin: 48px auto;
    max-width: 860px;
}

.density-bars {
    display: flex;
    flex-direction: column;
    gap: 14px;
    margin-bottom: 40px;
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: 32px;
    backdrop-filter: blur(12px);
}

.density-bars-title {
    font-family: var(--font-display);
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.density-bars-title svg {
    color: var(--accent-1);
    flex-shrink: 0;
}

.density-bar-row {
    display: grid;
    grid-template-columns: 110px 1fr 130px;
    align-items: center;
    gap: 16px;
}

.density-bar-label {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-align: right;
    font-family: var(--font-body);
}

.density-bar-track {
    height: 28px;
    background: rgba(255, 255, 255, 0.02);
    border-radius: 6px;
    position: relative;
    overflow: hidden;
}

.density-bar-fill {
    height: 100%;
    border-radius: 6px;
    position: relative;
    transition: width 1s var(--ease-out-expo);
}

.density-bar-fill::after {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    width: 60px;
    background: linear-gradient(to left, rgba(255, 255, 255, 0.08), transparent);
    border-radius: 0 6px 6px 0;
}

.density-bar-value {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.chart-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    overflow: hidden;
    backdrop-filter: blur(12px);
}

.chart-table thead th {
    padding: 14px 18px;
    text-align: left;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--text-tertiary);
    border-bottom: 1px solid var(--border-subtle);
    background: rgba(6, 182, 212, 0.03);
}

.chart-table tbody td {
    padding: 13px 18px;
    font-size: 0.88rem;
    border-bottom: 1px solid rgba(6, 182, 212, 0.04);
    color: var(--text-secondary);
}

.chart-table tbody tr:last-child td {
    border-bottom: none;
}

.chart-table tbody tr:hover td {
    background: rgba(6, 182, 212, 0.04);
}

.chart-table .mono {
    font-family: var(--font-mono);
    font-weight: 500;
    color: var(--accent-1);
}

/* --- Scale Balance Visual --- */
.scale-visual {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
    margin: 48px auto;
    max-width: 860px;
}

.scale-card {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: 24px;
    text-align: center;
    backdrop-filter: blur(12px);
    transition: all var(--transition-med);
}

.scale-card:hover {
    border-color: var(--border-glow);
    transform: translateY(-3px);
    box-shadow: 0 12px 36px rgba(6, 182, 212, 0.06);
}

.scale-card-icon {
    width: 44px;
    height: 44px;
    margin: 0 auto 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
    color: var(--accent-1);
}

.scale-card-icon.icon-water {
    background: rgba(6, 182, 212, 0.12);
    color: #06b6d4;
}

.scale-card-icon.icon-honey {
    background: rgba(139, 92, 246, 0.12);
    color: #8b5cf6;
}

.scale-card-icon.icon-oil {
    background: rgba(234, 179, 8, 0.12);
    color: #eab308;
}

.scale-card-icon.icon-milk {
    background: rgba(99, 102, 241, 0.12);
    color: #6366f1;
}

.scale-card-icon.icon-ethanol {
    background: rgba(236, 72, 153, 0.12);
    color: #ec4899;
}

.scale-card-icon.icon-mercury {
    background: rgba(168, 162, 158, 0.12);
    color: #a8a29e;
}

.scale-card-icon.icon-glycerin {
    background: rgba(34, 197, 94, 0.12);
    color: #22c55e;
}

.scale-card-icon.icon-coconut {
    background: rgba(251, 146, 60, 0.12);
    color: #fb923c;
}

.scale-card-substance {
    font-family: var(--font-display);
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.scale-card-density {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-tertiary);
    margin-bottom: 12px;
}

.scale-card-value {
    font-family: var(--font-mono);
    font-size: 1.3rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 4px;
}

.scale-card-unit {
    font-size: 0.75rem;
    color: var(--text-tertiary);
    font-weight: 500;
}

/* --- Reverse Conversion Visual --- */
.reverse-visual {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-xl);
    padding: 36px;
    margin: 48px auto;
    max-width: 720px;
    backdrop-filter: blur(12px);
}

.reverse-formula {
    text-align: center;
    margin-bottom: 28px;
}

.reverse-formula .formula-main {
    margin-bottom: 0;
}

.reverse-table {
    width: 100%;
    border-collapse: collapse;
}

.reverse-table thead th {
    padding: 12px 16px;
    text-align: left;
    font-size: 0.73rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--text-tertiary);
    border-bottom: 1px solid var(--border-subtle);
}

.reverse-table tbody td {
    padding: 11px 16px;
    font-size: 0.88rem;
    border-bottom: 1px solid rgba(6, 182, 212, 0.04);
    color: var(--text-secondary);
}

.reverse-table tbody tr:last-child td {
    border-bottom: none;
}

.reverse-table .mono {
    font-family: var(--font-mono);
    font-weight: 500;
    color: var(--accent-1);
}

/* --- Step Cards (Convert How-To) --- */
.steps-visual {
    display: flex;
    flex-direction: column;
    gap: 20px;
    margin: 48px auto;
    max-width: 720px;
}

.step-visual-card {
    display: flex;
    gap: 20px;
    align-items: flex-start;
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: 28px;
    backdrop-filter: blur(12px);
    transition: all var(--transition-med);
}

.step-visual-card:hover {
    border-color: var(--border-glow);
    background: var(--bg-card-hover);
    transform: translateX(4px);
    box-shadow: 0 8px 32px rgba(6, 182, 212, 0.06);
}

.step-visual-number {
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
    color: #06080c;
    font-family: var(--font-display);
    font-weight: 800;
    font-size: 1.1rem;
    border-radius: 12px;
}

.step-visual-content h3 {
    font-family: var(--font-display);
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 6px;
}

.step-visual-content p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
    margin: 0;
}

.step-visual-content .mono {
    font-family: var(--font-mono);
    color: var(--accent-1);
    font-weight: 500;
}

/* --- Practical Examples Grid --- */
.examples-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
    margin: 32px auto 0;
    max-width: 720px;
}

.example-card {
    background: rgba(6, 182, 212, 0.04);
    border: 1px solid rgba(6, 182, 212, 0.08);
    border-radius: var(--radius-md);
    padding: 20px;
    text-align: center;
    transition: all var(--transition-fast);
}

.example-card:hover {
    border-color: rgba(6, 182, 212, 0.2);
    background: rgba(6, 182, 212, 0.06);
}

.example-card-icon {
    width: 40px;
    height: 40px;
    margin: 0 auto 10px;
    color: var(--accent-1);
}

.example-card-icon svg {
    width: 100%;
    height: 100%;
}

.example-card h4 {
    font-family: var(--font-display);
    font-size: 0.88rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 6px;
}

.example-card p {
    color: var(--text-secondary);
    font-size: 0.8rem;
    line-height: 1.5;
    margin: 0;
}

/* --- Content Section Responsive --- */
@media (max-width: 1024px) {
    .formula-examples {
        grid-template-columns: 1fr;
    }

    .examples-grid {
        grid-template-columns: 1fr 1fr;
    }

    .density-bar-row {
        grid-template-columns: 90px 1fr 110px;
    }
}

@media (max-width: 768px) {
    .flow-diagram {
        flex-direction: column;
        gap: 0;
    }

    .flow-node {
        max-width: 100%;
        min-width: 0;
        width: 100%;
    }

    .flow-arrow {
        transform: rotate(90deg);
        width: auto;
        height: 36px;
    }

    .formula-main {
        font-size: 1.1rem;
        padding: 16px;
    }

    .formula-visual {
        padding: 24px;
    }

    .scale-visual {
        grid-template-columns: 1fr 1fr;
    }

    .density-bar-row {
        grid-template-columns: 80px 1fr 100px;
        gap: 10px;
    }

    .density-bar-label {
        font-size: 0.78rem;
    }

    .chart-table {
        font-size: 0.82rem;
    }

    .chart-table thead th,
    .chart-table tbody td {
        padding: 10px 12px;
    }

    .examples-grid {
        grid-template-columns: 1fr;
    }

    .reverse-visual {
        padding: 24px;
    }
}

@media (max-width: 480px) {
    .scale-visual {
        grid-template-columns: 1fr;
    }

    .density-bar-row {
        grid-template-columns: 1fr;
        gap: 4px;
    }

    .density-bar-label {
        text-align: left;
    }

    .density-bar-value {
        text-align: left;
        padding-left: 4px;
    }

    .step-visual-card {
        flex-direction: column;
        text-align: center;
        align-items: center;
    }

    .formula-examples {
        gap: 12px;
    }

    .chart-table-wrap {
        overflow-x: auto;
        margin: 0 -16px;
        padding: 0 16px;
    }
}

/* ═══ Sub-Calculators Showcase Grid (Homepage) ═══ */
.subcalc-showcase-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(270px, 1fr));
    gap: 20px;
    margin-top: 40px;
}

.subcalc-feature-card {
    background: var(--bg-card);
    backdrop-filter: blur(20px) saturate(1.2);
    -webkit-backdrop-filter: blur(20px) saturate(1.2);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    padding: 24px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    text-decoration: none;
    color: var(--text-primary);
    position: relative;
    overflow: hidden;
    transition: transform var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.subcalc-feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--grad-start), var(--grad-mid), var(--grad-end));
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.subcalc-feature-card:hover {
    transform: translateY(-4px);
    border-color: var(--border-glow);
    box-shadow: 0 12px 30px rgba(6, 182, 212, 0.15);
    text-decoration: none;
    color: var(--text-primary);
}

.subcalc-feature-card:hover::before {
    opacity: 1;
}

.subcalc-card-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 14px;
}

.subcalc-badge {
    font-size: 10px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    padding: 4px 10px;
    border-radius: 20px;
}

.subcalc-badge.badge-vol {
    background: rgba(6, 182, 212, 0.12);
    color: #06b6d4;
    border: 1px solid rgba(6, 182, 212, 0.2);
}

.subcalc-badge.badge-conc {
    background: rgba(99, 102, 241, 0.12);
    color: #818cf8;
    border: 1px solid rgba(99, 102, 241, 0.2);
}

.subcalc-badge.badge-clinical {
    background: rgba(139, 92, 246, 0.12);
    color: #a78bfa;
    border: 1px solid rgba(139, 92, 246, 0.2);
}

.subcalc-icon {
    font-size: 24px;
    line-height: 1;
}

.subcalc-card-title {
    font-family: var(--font-display);
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text-primary);
    transition: color var(--transition-fast);
}

.subcalc-feature-card:hover .subcalc-card-title {
    color: var(--accent-1);
}

.subcalc-card-desc {
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.5;
    margin-bottom: 20px;
}

.subcalc-card-footer {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 12px;
    font-weight: 600;
    color: var(--text-accent);
    transition: gap var(--transition-fast);
}

.subcalc-feature-card:hover .subcalc-card-footer {
    gap: 10px;
    color: var(--accent-3);
}

.subcalc-card-footer svg {
    transition: transform var(--transition-fast);
}

.subcalc-feature-card:hover .subcalc-card-footer svg {
    transform: translateX(3px);
}