/* ============================================================
   CHEMISTRY OCEAN — Prank & Education Stylesheet
   Aesthetic: Deep-sea bioluminescence × high-tech alert
   ============================================================ */

/* ── CSS Variables ── */
:root {
    /* Deep ocean palette */
    --abyss:        #040a14;
    --deep:         #071422;
    --trench:       #0b1e30;
    --mid:          #112a3e;
    --surface:      #163a54;

    /* Bioluminescent & Alert accents */
    --cyan:         #00e5ff;
    --cyan-dim:     #00e5ff33;
    --cyan-glow:    #00e5ff88;
    --teal:         #00bfa5;
    --teal-dim:     #00bfa533;
    --electric:     #4fc3f7;
    --violet:       #b388ff;
    --amber:        #ffab40;
    --amber-dim:    #ffab4033;
    --neon-red:     #ff3366;
    --neon-red-glow: rgba(255, 51, 102, 0.4);

    /* Text */
    --text-primary:   #e0f0ff;
    --text-secondary: #8badc4;
    --text-muted:     #4a6a82;

    /* Surfaces */
    --card-bg:      rgba(11, 30, 48, 0.7);
    --card-border:  rgba(0, 229, 255, 0.12);
    --glass:        rgba(7, 20, 34, 0.85);
    --glass-border: rgba(0, 229, 255, 0.18);

    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 3rem;
    --space-xl: 5rem;
    --space-2xl: 8rem;

    /* Type */
    --font-display: 'Cormorant Garamond', serif;
    --font-body:    'DM Sans', sans-serif;
    --font-mono:    'JetBrains Mono', monospace;

    /* Misc */
    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 22px;
    --transition: 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
    font-size: 16px;
}

body {
    font-family: var(--font-body);
    background: var(--abyss);
    color: var(--text-primary);
    overflow-x: hidden;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
button { border: none; background: none; cursor: pointer; font-family: inherit; color: inherit; }
ul { list-style: none; }

/* ── Cursor Glow ── */
.cursor-glow {
    position: fixed;
    width: 500px;
    height: 500px;
    border-radius: 50%;
    background: radial-gradient(circle, var(--cyan-dim) 0%, transparent 70%);
    pointer-events: none;
    z-index: 9999;
    transform: translate(-50%, -50%);
    opacity: 0;
    transition: opacity 0.4s;
    mix-blend-mode: screen;
}

body:hover .cursor-glow { opacity: 1; }

/* ── Bubble Canvas ── */
#bubbleCanvas {
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 100%;
    z-index: 0;
    pointer-events: none;
}

/* ── Container ── */
.container {
    width: 100%;
    max-width: 1240px;
    margin: 0 auto;
    padding: 0 var(--space-md);
}

/* ============================================================
   NAVBAR
   ============================================================ */
.navbar {
    position: fixed;
    top: 0; left: 0;
    width: 100%;
    z-index: 1000;
    padding: var(--space-sm) 0;
    transition: background var(--transition), box-shadow var(--transition), padding var(--transition);
}

.navbar.scrolled {
    background: var(--glass);
    backdrop-filter: blur(20px) saturate(1.4);
    box-shadow: 0 1px 0 var(--glass-border), 0 8px 32px rgba(0,0,0,0.4);
    padding: 0.6rem 0;
}

.nav-inner {
    max-width: 1240px;
    margin: 0 auto;
    padding: 0 var(--space-md);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    z-index: 1001;
}

.logo-icon { font-size: 1.6rem; }
.logo-accent { color: var(--cyan); }

.nav-links {
    display: flex;
    gap: var(--space-lg);
}

.nav-link {
    font-size: 0.88rem;
    font-weight: 500;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    color: var(--text-secondary);
    position: relative;
    transition: color var(--transition);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px; left: 0;
    width: 0; height: 2px;
    background: var(--cyan);
    border-radius: 1px;
    transition: width var(--transition);
}

.nav-link:hover { color: var(--text-primary); }
.nav-link:hover::after { width: 100%; }

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    z-index: 1001;
}

.nav-toggle span {
    width: 24px; height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition);
}

.nav-toggle.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.nav-toggle.active span:nth-child(2) { opacity: 0; }
.nav-toggle.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* ============================================================
   HERO / PRANK SECTION
   ============================================================ */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    padding-top: 80px;
}

.hero-bg {
    position: absolute;
    inset: 0;
    z-index: 0;
}

.hero-bg-img {
    width: 100%; height: 100%;
    object-fit: cover;
    transform: scale(1.05);
    animation: heroZoom 20s ease-in-out infinite alternate;
}

@keyframes heroZoom {
    0%   { transform: scale(1.05); }
    100% { transform: scale(1.12); }
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background:
        linear-gradient(180deg, var(--abyss) 0%, transparent 30%, transparent 60%, var(--abyss) 100%),
        radial-gradient(ellipse at 50% 40%, rgba(255, 51, 102, 0.12) 0%, transparent 70%),
        radial-gradient(ellipse at 30% 50%, rgba(0, 229, 255, 0.08) 0%, transparent 60%);
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 860px;
    padding: var(--space-lg) var(--space-md);
}

/* Alert badge */
.alert-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.5rem 1.2rem;
    border-radius: 50px;
    background: rgba(255, 51, 102, 0.15);
    border: 1px solid var(--neon-red);
    box-shadow: 0 0 20px var(--neon-red-glow);
    font-family: var(--font-mono);
    font-size: 0.8rem;
    font-weight: 700;
    color: #ff80a0;
    letter-spacing: 0.08em;
    margin-bottom: var(--space-md);
    animation: badgePulse 2s infinite;
}

@keyframes badgePulse {
    0%, 100% { box-shadow: 0 0 15px var(--neon-red-glow); }
    50%      { box-shadow: 0 0 35px var(--neon-red-glow); }
}

.pulse-dot {
    width: 8px; height: 8px;
    border-radius: 50%;
    background: var(--neon-red);
    box-shadow: 0 0 10px var(--neon-red);
    animation: blink 1s infinite;
}

@keyframes blink { 0%, 100% { opacity: 1; } 50% { opacity: 0.3; } }

.hero-title {
    font-family: var(--font-display);
    font-weight: 700;
    line-height: 0.95;
    margin-bottom: var(--space-md);
}

.title-line {
    display: block;
    font-size: clamp(3rem, 8vw, 6rem);
}

.title-line.accent {
    color: var(--cyan);
    text-shadow: 0 0 40px var(--cyan-dim), 0 0 100px rgba(0, 229, 255, 0.2);
}

/* Punchline highlight card */
.punchline-card {
    background: rgba(7, 20, 34, 0.85);
    border: 1.5px solid var(--cyan);
    border-radius: var(--radius-lg);
    padding: var(--space-md) var(--space-lg);
    margin: 0 auto var(--space-md);
    box-shadow: 0 10px 40px rgba(0, 229, 255, 0.15);
    backdrop-filter: blur(12px);
}

.hero-subtitle-highlight {
    font-family: var(--font-display);
    font-size: clamp(1.3rem, 3.5vw, 2rem);
    font-weight: 600;
    color: #ffffff;
    line-height: 1.4;
    text-shadow: 0 2px 10px rgba(0,0,0,0.5);
}

/* Live Timer Box */
.timer-box {
    display: inline-flex;
    align-items: center;
    gap: 0.8rem;
    background: rgba(4, 10, 20, 0.8);
    border: 1px solid var(--card-border);
    padding: 0.6rem 1.4rem;
    border-radius: 50px;
    margin-bottom: var(--space-lg);
}

.timer-label {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.timer-count {
    font-family: var(--font-mono);
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--amber);
    text-shadow: 0 0 10px var(--amber-dim);
}

.hero-actions {
    display: flex;
    gap: var(--space-sm);
    justify-content: center;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.85rem 1.8rem;
    border-radius: 50px;
    font-size: 0.9rem;
    font-weight: 600;
    letter-spacing: 0.03em;
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: linear-gradient(135deg, var(--cyan) 0%, var(--teal) 100%);
    color: var(--abyss);
    box-shadow: 0 4px 24px rgba(0, 229, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 40px rgba(0, 229, 255, 0.45);
}

.btn-ghost {
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    background: var(--glass);
    backdrop-filter: blur(10px);
}

.btn-ghost:hover {
    border-color: var(--cyan);
    background: rgba(0, 229, 255, 0.06);
    transform: translateY(-2px);
}

/* Scroll hint */
.hero-scroll-hint {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.6rem;
    z-index: 2;
}

.hero-scroll-hint span {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--text-muted);
}

.scroll-line {
    width: 1px; height: 40px;
    background: linear-gradient(180deg, var(--cyan), transparent);
    animation: scrollPulse 2s ease-in-out infinite;
}

@keyframes scrollPulse {
    0%, 100% { opacity: 0.3; transform: scaleY(0.6); }
    50%      { opacity: 1;   transform: scaleY(1); }
}

/* Floating molecules */
.hero-molecules {
    position: absolute;
    inset: 0;
    z-index: 1;
    pointer-events: none;
}

.molecule {
    position: absolute;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--cyan);
    opacity: 0.15;
    animation: moleculeFloat 12s ease-in-out infinite;
}

.molecule-1 { top: 20%; left: 8%;  animation-delay: 0s; }
.molecule-2 { top: 35%; right: 12%; animation-delay: 2s; }
.molecule-3 { bottom: 30%; left: 15%; animation-delay: 4s; }
.molecule-4 { top: 15%; right: 25%; animation-delay: 6s; }
.molecule-5 { bottom: 20%; right: 8%; animation-delay: 8s; }

@keyframes moleculeFloat {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    33%      { transform: translateY(-20px) rotate(5deg); }
    66%      { transform: translateY(10px) rotate(-3deg); }
}

/* ============================================================
   SECTIONS — Shared
   ============================================================ */
.section {
    position: relative;
    z-index: 1;
    padding: var(--space-2xl) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-xl);
}

.section-tag {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--cyan);
    padding: 0.4rem 1rem;
    border: 1px solid var(--cyan-dim);
    border-radius: 50px;
    margin-bottom: var(--space-sm);
}

.section-title {
    font-family: var(--font-display);
    font-size: clamp(2.2rem, 5vw, 3.5rem);
    font-weight: 700;
    line-height: 1.15;
    margin-bottom: var(--space-sm);
}

.section-desc {
    font-size: 1.05rem;
    color: var(--text-secondary);
    max-width: 520px;
    margin: 0 auto;
}

/* ============================================================
   RULES OF STUDYING SECTION
   ============================================================ */
.study-rules {
    background: radial-gradient(ellipse at 50% 50%, rgba(0, 229, 255, 0.04) 0%, transparent 60%);
}

.rules-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-md);
}

.rule-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    text-align: center;
    transition: all var(--transition);
    backdrop-filter: blur(10px);
}

.rule-card:hover {
    border-color: var(--cyan);
    transform: translateY(-6px);
    box-shadow: 0 15px 40px rgba(0, 229, 255, 0.1);
}

.rule-icon {
    font-size: 2.2rem;
    margin-bottom: var(--space-sm);
}

.rule-title {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.6rem;
}

.rule-desc {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ============================================================
   ELEMENTS
   ============================================================ */
.elements {
    background: radial-gradient(ellipse at 50% 0%, rgba(0, 229, 255, 0.04) 0%, transparent 40%);
}

.elements-showcase {
    display: grid;
    grid-template-columns: 1fr 320px;
    gap: var(--space-lg);
    align-items: start;
}

.element-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(72px, 1fr));
    gap: 6px;
}

.element-tile {
    aspect-ratio: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
}

.element-tile::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, var(--cyan-dim), transparent);
    opacity: 0;
    transition: opacity var(--transition);
}

.element-tile:hover {
    border-color: var(--cyan);
    transform: scale(1.08);
    z-index: 2;
    box-shadow: 0 4px 20px rgba(0, 229, 255, 0.2);
}

.element-tile:hover::before { opacity: 1; }

.element-tile.active {
    border-color: var(--cyan);
    background: rgba(0, 229, 255, 0.1);
    box-shadow: 0 0 20px var(--cyan-dim);
}

.el-number {
    font-family: var(--font-mono);
    font-size: 0.55rem;
    color: var(--text-muted);
    position: relative; z-index: 1;
}

.el-symbol {
    font-family: var(--font-display);
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.2;
    position: relative; z-index: 1;
}

.el-name {
    font-size: 0.5rem;
    color: var(--text-muted);
    letter-spacing: 0.02em;
    position: relative; z-index: 1;
    text-overflow: ellipsis; white-space: nowrap; overflow: hidden; max-width: 90%;
}

/* Element category coloring */
.element-tile[data-category="noble-gas"]       { border-left: 2px solid var(--violet); }
.element-tile[data-category="alkali-metal"]    { border-left: 2px solid var(--amber); }
.element-tile[data-category="alkaline-earth"]  { border-left: 2px solid #ff7043; }
.element-tile[data-category="transition"]      { border-left: 2px solid var(--teal); }
.element-tile[data-category="nonmetal"]        { border-left: 2px solid var(--cyan); }
.element-tile[data-category="metalloid"]       { border-left: 2px solid #aed581; }
.element-tile[data-category="halogen"]         { border-left: 2px solid #f48fb1; }
.element-tile[data-category="post-transition"] { border-left: 2px solid #90a4ae; }

/* Detail panel */
.element-detail {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    backdrop-filter: blur(12px);
    position: sticky;
    top: 100px;
    min-height: 320px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.detail-placeholder {
    text-align: center;
    color: var(--text-muted);
}

.detail-placeholder .detail-icon {
    font-size: 2.5rem;
    display: block;
    margin-bottom: var(--space-sm);
}

.detail-content { width: 100%; }

.detail-header {
    display: flex;
    align-items: flex-end;
    gap: var(--space-sm);
    margin-bottom: var(--space-md);
    padding-bottom: var(--space-md);
    border-bottom: 1px solid var(--card-border);
}

.detail-symbol {
    font-family: var(--font-display);
    font-size: 4rem;
    font-weight: 700;
    line-height: 1;
    color: var(--cyan);
    text-shadow: 0 0 30px var(--cyan-dim);
}

.detail-name {
    font-family: var(--font-display);
    font-size: 1.4rem;
    font-weight: 600;
    margin-bottom: 0.2rem;
}

.detail-number-cat {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-muted);
}

.detail-props {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.8rem;
}

.detail-prop {
    padding: 0.6rem;
    background: rgba(0, 229, 255, 0.03);
    border-radius: var(--radius-sm);
    border: 1px solid rgba(0, 229, 255, 0.05);
}

.detail-prop-label {
    font-family: var(--font-mono);
    font-size: 0.6rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    margin-bottom: 0.2rem;
}

.detail-prop-value {
    font-size: 0.95rem;
    font-weight: 600;
}

/* ============================================================
   FORMULAS
   ============================================================ */
.formulas {
    background: radial-gradient(ellipse at 70% 70%, rgba(179, 136, 255, 0.03) 0%, transparent 50%);
}

.formulas-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-md);
}

.formula-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    transition: all var(--transition);
    backdrop-filter: blur(8px);
    position: relative;
    overflow: hidden;
}

.formula-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 2px;
    background: linear-gradient(90deg, var(--cyan), var(--violet), var(--teal));
    opacity: 0;
    transition: opacity var(--transition);
}

.formula-card:hover {
    border-color: var(--cyan-dim);
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.3);
}

.formula-card:hover::before { opacity: 1; }

.formula-category {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--teal);
    margin-bottom: var(--space-sm);
}

.formula-expression {
    font-family: var(--font-display);
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-md);
    line-height: 1.3;
}

.formula-expression sub {
    font-size: 0.6em;
    vertical-align: baseline;
    position: relative; bottom: -0.2em;
}

.formula-vars {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.formula-vars span {
    font-size: 0.8rem;
    color: var(--text-muted);
    padding-left: 0.8rem;
    position: relative;
}

.formula-vars span::before {
    content: '›';
    position: absolute; left: 0;
    color: var(--cyan);
}

/* ============================================================
   MODAL OVERLAY
   ============================================================ */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(4, 10, 20, 0.85);
    backdrop-filter: blur(15px);
    z-index: 10000;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.modal-overlay.active {
    opacity: 1;
    pointer-events: auto;
}

.modal-card {
    background: var(--deep);
    border: 1.5px solid var(--cyan);
    border-radius: var(--radius-lg);
    padding: var(--space-xl) var(--space-lg);
    max-width: 480px;
    width: 90%;
    text-align: center;
    box-shadow: 0 0 60px rgba(0, 229, 255, 0.3);
    transform: scale(0.9);
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.modal-overlay.active .modal-card {
    transform: scale(1);
}

.modal-icon {
    font-size: 3.5rem;
    margin-bottom: var(--space-sm);
}

.modal-title {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
}

.modal-desc {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: var(--space-lg);
    line-height: 1.6;
}

/* ============================================================
   FOOTER
   ============================================================ */
.footer {
    position: relative;
    z-index: 1;
    padding: var(--space-xl) 0 var(--space-lg);
    border-top: 1px solid var(--card-border);
    background: var(--deep);
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--space-xl);
}

.footer-brand {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.footer-brand .logo-text {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
}

.footer-tagline {
    font-size: 0.88rem;
    color: var(--text-muted);
    margin-top: 0.3rem;
}

.footer-links {
    display: flex;
    gap: var(--space-xl);
}

.footer-col {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.footer-col h4 {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--cyan);
    margin-bottom: 0.5rem;
}

.footer-col a {
    font-size: 0.9rem;
    color: var(--text-muted);
    transition: color var(--transition);
}

.footer-col a:hover { color: var(--text-primary); }

.footer-bottom {
    padding-top: var(--space-md);
    border-top: 1px solid var(--card-border);
    text-align: center;
}

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

/* ============================================================
   REVEAL ANIMATIONS
   ============================================================ */
[data-reveal] {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}

[data-reveal].revealed {
    opacity: 1;
    transform: translateY(0);
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 1024px) {
    .rules-grid { grid-template-columns: repeat(2, 1fr); }
    .formulas-grid { grid-template-columns: repeat(2, 1fr); }
    .elements-showcase { grid-template-columns: 1fr; }
    .element-detail { position: static; }
}

@media (max-width: 768px) {
    .rules-grid { grid-template-columns: 1fr; }
    .formulas-grid { grid-template-columns: 1fr; }
    .element-grid { grid-template-columns: repeat(auto-fill, minmax(60px, 1fr)); }

    .nav-links {
        position: fixed;
        top: 0; right: -100%;
        width: 280px; height: 100vh;
        background: var(--deep);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: var(--space-lg);
        transition: right var(--transition);
        box-shadow: -10px 0 40px rgba(0,0,0,0.5);
    }

    .nav-links.open { right: 0; }
    .nav-toggle { display: flex; }

    .footer-inner {
        flex-direction: column;
        gap: var(--space-lg);
    }
}