/* ============================================
   Chemical Laboratory - Apple Liquid Glass UI
   ============================================ */

/* CSS Variables */
:root {
    /* Light theme */
    --bg-primary: #f5f5f7;
    --bg-secondary: #ffffff;
    --bg-gradient: linear-gradient(135deg, #e8eaf6 0%, #f5f5f7 30%, #e3f2fd 60%, #f5f5f7 100%);
    --text-primary: #1d1d1f;
    --text-secondary: #6e6e73;
    --text-tertiary: #86868b;
    --accent: #007aff;
    --accent-light: rgba(0, 122, 255, 0.1);
    --accent-glow: rgba(0, 122, 255, 0.15);
    --glass-bg: rgba(255, 255, 255, 0.12);
    --glass-border: rgba(255, 255, 255, 0.4);
    --glass-shadow: rgba(0, 0, 0, 0.04);
    --glass-highlight: rgba(255, 255, 255, 0.7);
    --glass-blur: 8px;
    --glass-saturate: 200%;
    --card-bg: rgba(255, 255, 255, 0.15);
    --card-border: rgba(255, 255, 255, 0.5);
    --input-bg: rgba(255, 255, 255, 0.2);
    --input-border: rgba(255, 255, 255, 0.4);
    --divider: rgba(0, 0, 0, 0.06);
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.04);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.06);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.08);
    --shadow-glow: 0 0 20px rgba(0, 122, 255, 0.1);
    --orb-1: rgba(100, 180, 255, 0.12);
    --orb-2: rgba(180, 100, 255, 0.08);
    --orb-3: rgba(100, 255, 200, 0.08);
    --nav-bg: rgba(255, 255, 255, 0.18);
    --tab-active-bg: rgba(255, 255, 255, 0.35);
    --chip-bg: rgba(0, 122, 255, 0.08);
    --chip-border: rgba(0, 122, 255, 0.2);
    --chip-hover: rgba(0, 122, 255, 0.15);
    --success: #34c759;
    --warning: #ff9500;
    --danger: #ff3b30;
    --reaction-arrow: #007aff;
    --gas-color: #34c759;
    --precipitate-color: #ff9500;
    --condition-color: #af52de;
}

[data-theme="dark"] {
    --bg-primary: #0a0e1a;
    --bg-secondary: #111827;
    --bg-gradient: linear-gradient(135deg, #0a0e1a 0%, #0f172a 30%, #0a1628 60%, #0a0e1a 100%);
    --text-primary: #f5f5f7;
    --text-secondary: #a1a1aa;
    --text-tertiary: #71717a;
    --accent: #0a84ff;
    --accent-light: rgba(10, 132, 255, 0.15);
    --accent-glow: rgba(10, 132, 255, 0.2);
    --glass-bg: rgba(255, 255, 255, 0.06);
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-shadow: rgba(0, 0, 0, 0.2);
    --glass-highlight: rgba(255, 255, 255, 0.08);
    --glass-blur: 10px;
    --card-bg: rgba(255, 255, 255, 0.06);
    --card-border: rgba(255, 255, 255, 0.1);
    --input-bg: rgba(255, 255, 255, 0.06);
    --input-border: rgba(255, 255, 255, 0.12);
    --divider: rgba(255, 255, 255, 0.06);
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.2);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.25);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.3);
    --shadow-glow: 0 0 20px rgba(10, 132, 255, 0.15);
    --orb-1: rgba(10, 132, 255, 0.08);
    --orb-2: rgba(160, 80, 255, 0.06);
    --orb-3: rgba(0, 200, 150, 0.06);
    --nav-bg: rgba(255, 255, 255, 0.06);
    --tab-active-bg: rgba(255, 255, 255, 0.1);
    --chip-bg: rgba(10, 132, 255, 0.12);
    --chip-border: rgba(10, 132, 255, 0.25);
    --chip-hover: rgba(10, 132, 255, 0.2);
    --reaction-arrow: #0a84ff;
    --gas-color: #30d158;
    --precipitate-color: #ff9f0a;
    --condition-color: #bf5af2;
}

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'SF Pro Text', 'Helvetica Neue', Arial, sans-serif;
    background: var(--bg-gradient);
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
    transition: background 0.6s ease, color 0.4s ease;
}

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

.ambient-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    animation: orbFloat 20s ease-in-out infinite;
}

.orb-1 {
    width: 500px;
    height: 500px;
    background: var(--orb-1);
    top: -10%;
    left: -5%;
    animation-delay: 0s;
}

.orb-2 {
    width: 400px;
    height: 400px;
    background: var(--orb-2);
    top: 40%;
    right: -8%;
    animation-delay: -7s;
}

.orb-3 {
    width: 350px;
    height: 350px;
    background: var(--orb-3);
    bottom: -5%;
    left: 30%;
    animation-delay: -14s;
}

@keyframes orbFloat {
    0%, 100% { transform: translate(0, 0) scale(1); }
    25% { transform: translate(30px, -20px) scale(1.05); }
    50% { transform: translate(-20px, 30px) scale(0.95); }
    75% { transform: translate(15px, 15px) scale(1.02); }
}

/* Glass Panel Base */
.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(var(--glass-blur)) saturate(var(--glass-saturate));
    -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(var(--glass-saturate));
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    box-shadow: var(--shadow-sm), inset 0 1px 0 var(--glass-highlight);
}

.glass-card {
    background: var(--card-bg);
    backdrop-filter: blur(var(--glass-blur)) saturate(var(--glass-saturate));
    -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(var(--glass-saturate));
    border: 1px solid var(--card-border);
    border-radius: 20px;
    box-shadow: var(--shadow-md), inset 0 1px 0 var(--glass-highlight);
}

.glass-input {
    background: var(--input-bg);
    backdrop-filter: blur(6px) saturate(180%);
    -webkit-backdrop-filter: blur(6px) saturate(180%);
    border: 1px solid var(--input-border);
    border-radius: 12px;
    transition: all 0.3s ease;
}

.glass-input:focus-within {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-light), var(--shadow-glow);
}

.glass-btn {
    background: var(--glass-bg);
    backdrop-filter: blur(6px) saturate(180%);
    -webkit-backdrop-filter: blur(6px) saturate(180%);
    border: 1px solid var(--glass-border);
    border-radius: 10px;
    cursor: pointer;
    transition: transform 0.2s ease-out, background 0.25s ease, box-shadow 0.25s ease;
}

.glass-btn:hover {
    background: var(--tab-active-bg);
    animation: elasticHover 0.5s cubic-bezier(0.2, 1.4, 0.4, 1) forwards;
    box-shadow: var(--shadow-md);
}

.glass-btn:active {
    transform: scale(0.96);
    transition: transform 0.08s ease;
    box-shadow: var(--shadow-sm);
}

.glass-chip {
    background: var(--chip-bg);
    border: 1px solid var(--chip-border);
    border-radius: 20px;
    padding: 6px 14px;
    font-size: 0.8rem;
    color: var(--accent);
    cursor: pointer;
    transition: all 0.25s ease;
    white-space: nowrap;
    font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
}

.glass-chip:hover {
    background: var(--chip-hover);
    transform: translateY(-1px);
    box-shadow: 0 2px 8px var(--accent-light);
}

/* Toolbar */
.toolbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 24px;
    border-radius: 0;
    border-top: none;
    border-left: none;
    border-right: none;
    height: 56px;
}

.toolbar-left {
    display: flex;
    align-items: center;
    gap: 12px;
    min-width: 200px;
}

.app-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--text-primary);
}

.app-logo svg {
    opacity: 0.8;
}

.app-title {
    font-size: 0.95rem;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.toolbar-center {
    flex: 1;
    max-width: 480px;
    margin: 0 20px;
}

.search-box {
    position: relative;
    display: flex;
    align-items: center;
    padding: 0 14px;
    height: 36px;
}

.search-icon {
    color: var(--text-tertiary);
    flex-shrink: 0;
    margin-right: 8px;
}

.search-box input {
    background: none;
    border: none;
    outline: none;
    width: 100%;
    font-size: 0.85rem;
    color: var(--text-primary);
    font-family: inherit;
}

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

.suggestions-dropdown {
    position: absolute;
    top: calc(100% + 6px);
    left: 0;
    right: 0;
    max-height: 320px;
    overflow-y: auto;
    display: none;
    padding: 6px;
    z-index: 200;
}

.suggestions-dropdown.visible {
    display: block;
    animation: dropIn 0.2s ease;
}

.suggestion-item {
    padding: 8px 12px;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: background 0.15s, transform 0.2s ease-out;
    font-size: 0.85rem;
}

.suggestion-item:hover {
    background: var(--accent-light);
    animation: elasticHover 0.5s cubic-bezier(0.2, 1.4, 0.4, 1) forwards;
}

.suggestion-item .suggestion-type {
    font-size: 0.7rem;
    color: var(--text-tertiary);
    background: var(--glass-bg);
    padding: 2px 6px;
    border-radius: 4px;
}

.suggestion-item .suggestion-formula {
    font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
    font-weight: 500;
}

.toolbar-right {
    display: flex;
    align-items: center;
    gap: 8px;
}

.toolbar-btn {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    padding: 0;
}

a.toolbar-btn {
    text-decoration: none;
    cursor: pointer;
}

.toolbar-btn:hover {
    color: var(--accent);
}

.lang-label {
    font-size: 0.75rem;
    font-weight: 600;
}

/* Main Navigation */
.main-nav {
    position: fixed;
    top: 56px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 99;
    padding: 6px;
    border-radius: 14px;
    margin-top: 8px;
}

.nav-track {
    display: flex;
    position: relative;
}

.nav-indicator {
    position: absolute;
    height: 100%;
    background: var(--tab-active-bg);
    border-radius: 10px;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: var(--shadow-sm);
    pointer-events: none;
}

.nav-tab {
    position: relative;
    z-index: 1;
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 18px;
    background: none;
    border: none;
    border-radius: 10px;
    color: var(--text-secondary);
    font-size: 0.82rem;
    font-weight: 500;
    cursor: pointer;
    transition: color 0.3s ease;
    white-space: nowrap;
    font-family: inherit;
}

.nav-tab:hover {
    color: var(--text-primary);
}

.nav-tab.active {
    color: var(--accent);
}

.nav-tab svg {
    flex-shrink: 0;
}

/* Content Area */
.content-area {
    position: relative;
    z-index: 1;
    padding: 120px 32px 40px;
    max-width: 960px;
    margin: 0 auto;
    min-height: 100vh;
}

/* Module Pages */
.module-page {
    display: none;
    animation: pageIn 0.4s ease;
}

.module-page.active {
    display: block;
}

@keyframes pageIn {
    from {
        opacity: 0;
        transform: translateY(12px) scale(0.99);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.module-header {
    margin-bottom: 24px;
}

.module-title {
    font-size: 1.8rem;
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: 6px;
}

.module-desc {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* Reaction Input Area */
.reaction-input-area {
    padding: 24px;
    margin-bottom: 24px;
}

.input-row {
    display: flex;
    gap: 12px;
    margin-bottom: 16px;
}

.formula-input-wrapper {
    flex: 1;
    position: relative;
    display: flex;
    align-items: center;
    padding: 0 16px;
    height: 44px;
}

.formula-input-wrapper input {
    background: none;
    border: none;
    outline: none;
    width: 100%;
    font-size: 0.95rem;
    color: var(--text-primary);
    font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
    letter-spacing: 0.02em;
}

.formula-input-wrapper input::placeholder {
    color: var(--text-tertiary);
    font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', sans-serif;
}

.input-feedback {
    position: absolute;
    right: 12px;
    font-size: 0.75rem;
    color: var(--text-tertiary);
}

.primary-btn {
    padding: 0 24px;
    height: 44px;
    background: var(--accent);
    color: white;
    font-weight: 600;
    font-size: 0.85rem;
    border: none;
    letter-spacing: -0.01em;
    font-family: inherit;
}

.primary-btn:hover {
    background: var(--accent);
    opacity: 0.9;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px var(--accent-glow);
}

.quick-reactions {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    align-items: center;
}

.quick-label {
    font-size: 0.78rem;
    color: var(--text-tertiary);
    margin-right: 4px;
}

/* Result Area */
.result-area {
    margin-top: 8px;
}

/* Result Cards */
.result-card {
    background: var(--card-bg);
    backdrop-filter: blur(var(--glass-blur)) saturate(var(--glass-saturate));
    -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(var(--glass-saturate));
    border: 1px solid var(--card-border);
    border-radius: 20px;
    padding: 28px;
    margin-bottom: 16px;
    box-shadow: var(--shadow-md), inset 0 1px 0 var(--glass-highlight);
    animation: cardIn 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.result-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), inset 0 1px 0 var(--glass-highlight);
}

@keyframes cardIn {
    from {
        opacity: 0;
        transform: translateY(16px) scale(0.98);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.result-card h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 16px;
    letter-spacing: -0.02em;
    color: var(--text-primary);
}

/* Reaction Display */
.reaction-display {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    padding: 24px 16px;
    margin-bottom: 20px;
    flex-wrap: wrap;
    font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
    font-size: 1.3rem;
}

.reactant, .product {
    padding: 8px 16px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 10px;
    animation: fadeSlideIn 0.4s ease both;
    white-space: nowrap;
}

.reactant:nth-child(1) { animation-delay: 0.1s; }
.reactant:nth-child(2) { animation-delay: 0.2s; }
.reactant:nth-child(3) { animation-delay: 0.3s; }

.reaction-arrow {
    color: var(--reaction-arrow);
    font-size: 1.4rem;
    position: relative;
    animation: arrowDraw 0.6s ease 0.4s both;
}

.reaction-arrow .arrow-line {
    display: inline-block;
    border-bottom: 2px solid var(--reaction-arrow);
    width: 40px;
    vertical-align: middle;
    margin: 0 4px;
}

.reaction-arrow .condition {
    position: absolute;
    top: -22px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 0.7rem;
    color: var(--condition-color);
    white-space: nowrap;
    font-family: -apple-system, sans-serif;
    animation: fadeSlideIn 0.3s ease 0.6s both;
}

.product:nth-last-child(3) { animation-delay: 0.5s; }
.product:nth-last-child(2) { animation-delay: 0.6s; }
.product:nth-last-child(1) { animation-delay: 0.7s; }

@keyframes fadeSlideIn {
    from {
        opacity: 0;
        transform: translateX(-8px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes arrowDraw {
    from {
        opacity: 0;
        transform: scaleX(0);
    }
    to {
        opacity: 1;
        transform: scaleX(1);
    }
}

.gas-indicator {
    color: var(--gas-color);
    font-size: 0.9rem;
    animation: gasUp 1s ease infinite;
    display: inline-block;
}

.precipitate-indicator {
    color: var(--precipitate-color);
    font-size: 0.9rem;
    animation: precipDown 1s ease infinite;
    display: inline-block;
}

@keyframes gasUp {
    0%, 100% { transform: translateY(0); opacity: 1; }
    50% { transform: translateY(-4px); opacity: 0.7; }
}

@keyframes precipDown {
    0%, 100% { transform: translateY(0); opacity: 1; }
    50% { transform: translateY(4px); opacity: 0.7; }
}

/* Info Grid */
.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 12px;
}

.info-item {
    padding: 12px 16px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    transition: all 0.25s ease;
}

.info-item:hover {
    background: var(--tab-active-bg);
    transform: translateY(-1px);
}

.info-label {
    font-size: 0.72rem;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 4px;
}

.info-value {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
}

/* Tags */
.tag-row {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-top: 12px;
}

.tag {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 8px;
    font-size: 0.72rem;
    font-weight: 500;
    letter-spacing: 0.02em;
}

.tag-acid {
    background: rgba(255, 59, 48, 0.1);
    color: #ff3b30;
    border: 1px solid rgba(255, 59, 48, 0.2);
}

.tag-base {
    background: rgba(0, 122, 255, 0.1);
    color: #007aff;
    border: 1px solid rgba(0, 122, 255, 0.2);
}

.tag-salt {
    background: rgba(52, 199, 89, 0.1);
    color: #34c759;
    border: 1px solid rgba(52, 199, 89, 0.2);
}

.tag-oxide {
    background: rgba(255, 149, 0, 0.1);
    color: #ff9500;
    border: 1px solid rgba(255, 149, 0, 0.2);
}

.tag-organic {
    background: rgba(175, 82, 222, 0.1);
    color: #af52de;
    border: 1px solid rgba(175, 82, 222, 0.2);
}

.tag-danger {
    background: rgba(255, 59, 48, 0.1);
    color: #ff3b30;
    border: 1px solid rgba(255, 59, 48, 0.2);
}

.tag-safe {
    background: rgba(52, 199, 89, 0.1);
    color: #34c759;
    border: 1px solid rgba(52, 199, 89, 0.2);
}

.tag-neutral {
    background: var(--glass-bg);
    color: var(--text-secondary);
    border: 1px solid var(--glass-border);
}

.tag-clickable {
    cursor: pointer;
    transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.tag-clickable:hover {
    transform: scale(1.05);
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}

.reaction-type-popup-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.4);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10000;
    animation: fadeIn 0.2s ease;
}
.reaction-type-popup {
    max-width: 480px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    border-radius: 16px;
    padding: 0;
    animation: slideUp 0.25s ease;
    background: var(--bg-secondary);
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-lg);
}
.popup-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 24px 12px;
    border-bottom: 1px solid var(--glass-border);
}
.popup-header h3 {
    margin: 0;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
}
.popup-close {
    background: none;
    border: none;
    font-size: 1.1rem;
    color: var(--text-tertiary);
    cursor: pointer;
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: background 0.15s;
}
.popup-close:hover {
    background: var(--glass-bg);
    color: var(--text-primary);
}
.popup-body {
    padding: 16px 24px 24px;
}
.popup-desc {
    margin: 0 0 16px;
    font-size: 0.92rem;
    line-height: 1.6;
    color: var(--text-secondary);
}
.popup-body h4 {
    margin: 0 0 10px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
}
.popup-traits {
    margin: 0;
    padding-left: 20px;
    list-style: disc;
}
.popup-traits li {
    font-size: 0.88rem;
    line-height: 1.6;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

/* Footer */
.app-footer {
    display: flex;
    justify-content: center;
    padding: 24px 16px 32px;
}
.footer-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: 12px;
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 0.88rem;
    font-weight: 500;
    transition: color 0.2s, background 0.2s, transform 0.15s;
}
.footer-btn:hover {
    color: var(--accent);
    background: var(--accent-light);
    transform: translateY(-1px);
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}
@keyframes slideUp {
    from { transform: translateY(20px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

/* Equation Steps */
.equation-steps {
    margin: 16px 0;
    padding: 16px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
}

.equation-step {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    padding: 8px 0;
    border-bottom: 1px solid var(--divider);
    animation: stepIn 0.3s ease both;
}

.equation-step:last-child {
    border-bottom: none;
}

.step-number {
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--accent-light);
    color: var(--accent);
    border-radius: 50%;
    font-size: 0.72rem;
    font-weight: 600;
    flex-shrink: 0;
}

.step-content {
    font-size: 0.85rem;
    line-height: 1.5;
    font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
}

@keyframes stepIn {
    from { opacity: 0; transform: translateX(-8px); }
    to { opacity: 1; transform: translateX(0); }
}

.equation-step:nth-child(1) { animation-delay: 0.1s; }
.equation-step:nth-child(2) { animation-delay: 0.2s; }
.equation-step:nth-child(3) { animation-delay: 0.3s; }
.equation-step:nth-child(4) { animation-delay: 0.4s; }
.equation-step:nth-child(5) { animation-delay: 0.5s; }

/* 3D Viewer */
.viewer-3d-container {
    padding: 0;
    overflow: hidden;
    position: relative;
    margin-bottom: 16px;
}

.viewer-3d-canvas {
    width: 100%;
    height: 400px;
    position: relative;
}

.viewer-3d-canvas canvas {
    display: block;
    width: 100% !important;
    height: 100% !important;
}

.viewer-controls {
    position: absolute;
    bottom: 16px;
    right: 16px;
    display: flex;
    gap: 6px;
}

.viewer-ctrl-btn {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
    color: var(--text-secondary);
}

.viewer-ctrl-btn.active {
    background: var(--accent-light);
    border-color: var(--accent);
    color: var(--accent);
}

/* Description text */
.desc-block {
    margin-top: 16px;
    padding: 16px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    font-size: 0.85rem;
    line-height: 1.7;
    color: var(--text-secondary);
}

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

/* Organic structure display */
.organic-structure {
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 20px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 14px;
    margin-bottom: 16px;
    flex-wrap: wrap;
}

.structure-formula {
    font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--accent);
}

.structure-name {
    font-size: 1rem;
    color: var(--text-primary);
    font-weight: 500;
}

.structure-type {
    font-size: 0.8rem;
    color: var(--text-tertiary);
}

.functional-groups {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 12px;
}

.functional-group {
    padding: 6px 12px;
    background: var(--accent-light);
    border: 1px solid var(--accent-glow);
    border-radius: 8px;
    font-size: 0.78rem;
    color: var(--accent);
    font-weight: 500;
}

/* Bond visualization */
.bond-display {
    display: flex;
    gap: 16px;
    margin-top: 12px;
    flex-wrap: wrap;
}

.bond-item {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.82rem;
    color: var(--text-secondary);
}

.bond-line {
    width: 20px;
    height: 2px;
    background: var(--accent);
    border-radius: 1px;
}

.bond-line.double {
    height: 6px;
    border-top: 2px solid var(--accent);
    border-bottom: 2px solid var(--accent);
    background: none;
}

.bond-line.triple {
    height: 8px;
    border-top: 2px solid var(--accent);
    border-bottom: 2px solid var(--accent);
    background: none;
    position: relative;
}

.bond-line.triple::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--accent);
    transform: translateY(-50%);
}

/* Molecule 3D info cards */
.mol-info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: 10px;
}

.mol-info-item {
    padding: 10px 14px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 10px;
    text-align: center;
}

.mol-info-item .mol-label {
    font-size: 0.7rem;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 4px;
}

.mol-info-item .mol-value {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: var(--glass-border);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-tertiary);
}

/* Responsive */
@media (max-width: 768px) {
    .toolbar {
        padding: 8px 16px;
    }

    .toolbar-center {
        display: none;
    }

    .content-area {
        padding: 110px 16px 32px;
    }

    .nav-tab span {
        display: none;
    }

    .nav-tab {
        padding: 10px 14px;
    }

    .reaction-display {
        font-size: 1rem;
        gap: 10px;
    }

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

@media (max-width: 480px) {
    .app-title {
        display: none;
    }

    .input-row {
        flex-direction: column;
    }

    .primary-btn {
        width: 100%;
    }

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

/* Loading animation */
.loading-dots {
    display: inline-flex;
    gap: 4px;
}

.loading-dots span {
    width: 6px;
    height: 6px;
    background: var(--accent);
    border-radius: 50%;
    animation: dotPulse 1.2s ease infinite;
}

.loading-dots span:nth-child(2) { animation-delay: 0.2s; }
.loading-dots span:nth-child(3) { animation-delay: 0.4s; }

@keyframes dotPulse {
    0%, 100% { opacity: 0.3; transform: scale(0.8); }
    50% { opacity: 1; transform: scale(1); }
}

/* Error state */
.error-message {
    padding: 16px 20px;
    background: rgba(255, 59, 48, 0.08);
    border: 1px solid rgba(255, 59, 48, 0.15);
    border-radius: 12px;
    color: #ff3b30;
    font-size: 0.85rem;
    display: flex;
    align-items: center;
    gap: 10px;
    animation: cardIn 0.3s ease;
}

/* Empty state */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-tertiary);
}

.empty-state svg {
    opacity: 0.3;
    margin-bottom: 16px;
}

.empty-state p {
    font-size: 0.9rem;
}

/* Transition utilities */
.fade-enter {
    opacity: 0;
    transform: translateY(8px);
}

.fade-enter-active {
    opacity: 1;
    transform: translateY(0);
    transition: all 0.3s ease;
}

/* ============================================
   Interactive Feedback Enhancements
   ============================================ */

/* Ripple effect on buttons and chips */
.ripple-container {
    position: relative;
    overflow: hidden;
}

.ripple-effect {
    position: absolute;
    border-radius: 50%;
    background: var(--accent);
    opacity: 0.2;
    transform: scale(0);
    animation: rippleExpand 0.6s cubic-bezier(0.4, 0, 0.2, 1) forwards;
    pointer-events: none;
}

@keyframes rippleExpand {
    to {
        transform: scale(4);
        opacity: 0;
    }
}

/* Button press spring animation */
.primary-btn {
    position: relative;
    overflow: hidden;
    transition: transform 0.2s ease-out;
}

.primary-btn:hover {
    animation: elasticHover 0.5s cubic-bezier(0.2, 1.4, 0.4, 1) forwards;
}

.primary-btn:active {
    transform: scale(0.96);
    transition: all 0.08s ease;
}

.glass-chip {
    position: relative;
    overflow: hidden;
    transition: transform 0.2s ease-out;
}

.glass-chip:hover {
    animation: elasticHover 0.5s cubic-bezier(0.2, 1.4, 0.4, 1) forwards;
}

.glass-chip:active {
    transform: scale(0.93);
    transition: all 0.08s ease;
}

/* Elastic bounce keyframe */
@keyframes elasticHover {
    0% { transform: scale(1); }
    40% { transform: scale(1.1); }
    100% { transform: scale(1.05); }
}

/* Chip click burst particles */
.chip-burst {
    position: absolute;
    width: 4px;
    height: 4px;
    border-radius: 50%;
    background: var(--accent);
    pointer-events: none;
    animation: chipBurst 0.5s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

@keyframes chipBurst {
    0% {
        opacity: 1;
        transform: translate(0, 0) scale(1);
    }
    100% {
        opacity: 0;
        transform: translate(var(--tx), var(--ty)) scale(0);
    }
}

/* Input validation animated feedback */
.input-feedback {
    transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.input-feedback.valid {
    color: var(--success) !important;
    animation: feedbackPop 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.input-feedback.partial {
    color: var(--accent) !important;
    animation: feedbackPulse 1.5s ease infinite;
}

.input-feedback.invalid {
    color: var(--danger) !important;
    animation: feedbackShake 0.4s ease;
}

@keyframes feedbackPop {
    0% { transform: scale(0.5); opacity: 0; }
    60% { transform: scale(1.3); }
    100% { transform: scale(1); opacity: 1; }
}

@keyframes feedbackPulse {
    0%, 100% { opacity: 0.5; }
    50% { opacity: 1; }
}

@keyframes feedbackShake {
    0%, 100% { transform: translateX(0); }
    20% { transform: translateX(-3px); }
    40% { transform: translateX(3px); }
    60% { transform: translateX(-2px); }
    80% { transform: translateX(2px); }
}

/* Input focus glow pulse */
.formula-input-wrapper.input-valid {
    border-color: var(--success) !important;
    box-shadow: 0 0 0 3px rgba(52, 199, 89, 0.15), 0 0 12px rgba(52, 199, 89, 0.1);
}

.formula-input-wrapper.input-partial {
    border-color: var(--accent) !important;
    box-shadow: 0 0 0 3px var(--accent-light), 0 0 12px var(--accent-glow);
    animation: inputGlow 2s ease infinite;
}

.formula-input-wrapper.input-invalid {
    border-color: var(--danger) !important;
    box-shadow: 0 0 0 3px rgba(255, 59, 48, 0.1);
    animation: inputShake 0.4s ease;
}

@keyframes inputGlow {
    0%, 100% { box-shadow: 0 0 0 3px var(--accent-light), 0 0 8px var(--accent-glow); }
    50% { box-shadow: 0 0 0 4px var(--accent-light), 0 0 16px var(--accent-glow); }
}

@keyframes inputShake {
    0%, 100% { transform: translateX(0); }
    20% { transform: translateX(-4px); }
    40% { transform: translateX(4px); }
    60% { transform: translateX(-3px); }
    80% { transform: translateX(3px); }
}

/* Loading skeleton shimmer */
.skeleton-card {
    background: var(--card-bg);
    backdrop-filter: blur(var(--glass-blur)) saturate(var(--glass-saturate));
    border: 1px solid var(--card-border);
    border-radius: 20px;
    padding: 28px;
    margin-bottom: 16px;
    overflow: hidden;
    position: relative;
}

.skeleton-line {
    height: 14px;
    background: var(--glass-bg);
    border-radius: 7px;
    margin-bottom: 12px;
    position: relative;
    overflow: hidden;
}

.skeleton-line::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, transparent, var(--glass-highlight), transparent);
    animation: shimmer 1.5s ease infinite;
}

.skeleton-line.short { width: 40%; }
.skeleton-line.medium { width: 65%; }
.skeleton-line.long { width: 90%; }

.skeleton-title {
    height: 20px;
    width: 50%;
    background: var(--glass-bg);
    border-radius: 10px;
    margin-bottom: 20px;
    position: relative;
    overflow: hidden;
}

.skeleton-title::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, transparent, var(--glass-highlight), transparent);
    animation: shimmer 1.5s ease infinite;
}

@keyframes shimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

/* Success checkmark animation */
.success-check {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--success);
    color: white;
    font-size: 0.7rem;
    animation: checkPop 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes checkPop {
    0% { transform: scale(0) rotate(-45deg); opacity: 0; }
    60% { transform: scale(1.2) rotate(0deg); }
    100% { transform: scale(1) rotate(0deg); opacity: 1; }
}

/* Toast notification */
.toast-container {
    position: fixed;
    top: 70px;
    right: 24px;
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: 8px;
    pointer-events: none;
}

.toast {
    padding: 12px 20px;
    border-radius: 12px;
    font-size: 0.82rem;
    font-weight: 500;
    backdrop-filter: blur(12px) saturate(200%);
    -webkit-backdrop-filter: blur(12px) saturate(200%);
    box-shadow: var(--shadow-md);
    pointer-events: auto;
    animation: toastIn 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    display: flex;
    align-items: center;
    gap: 8px;
    max-width: 320px;
}

.toast.toast-success {
    background: rgba(52, 199, 89, 0.15);
    border: 1px solid rgba(52, 199, 89, 0.3);
    color: var(--success);
}

.toast.toast-error {
    background: rgba(255, 59, 48, 0.15);
    border: 1px solid rgba(255, 59, 48, 0.3);
    color: var(--danger);
}

.toast.toast-info {
    background: var(--accent-light);
    border: 1px solid var(--accent-glow);
    color: var(--accent);
}

.toast.toast-out {
    animation: toastOut 0.3s ease forwards;
}

@keyframes toastIn {
    from {
        opacity: 0;
        transform: translateX(40px) scale(0.9);
    }
    to {
        opacity: 1;
        transform: translateX(0) scale(1);
    }
}

@keyframes toastOut {
    to {
        opacity: 0;
        transform: translateX(40px) scale(0.9);
    }
}

/* Result card stagger entrance */
.result-card {
    opacity: 0;
    animation: cardIn 0.5s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.result-card:nth-child(1) { animation-delay: 0.05s; }
.result-card:nth-child(2) { animation-delay: 0.12s; }
.result-card:nth-child(3) { animation-delay: 0.19s; }
.result-card:nth-child(4) { animation-delay: 0.26s; }
.result-card:nth-child(5) { animation-delay: 0.33s; }

/* Info item hover micro-animation */
.info-item {
    transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.info-item:active {
    transform: scale(0.97);
}

/* Tag pulse on appear */
.tag {
    animation: tagAppear 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}

.tag:nth-child(1) { animation-delay: 0.05s; }
.tag:nth-child(2) { animation-delay: 0.1s; }
.tag:nth-child(3) { animation-delay: 0.15s; }
.tag:nth-child(4) { animation-delay: 0.2s; }

@keyframes tagAppear {
    from {
        opacity: 0;
        transform: scale(0.7);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

/* Functional group badge animation */
.functional-group {
    animation: badgeIn 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}

.functional-group:nth-child(1) { animation-delay: 0.05s; }
.functional-group:nth-child(2) { animation-delay: 0.1s; }
.functional-group:nth-child(3) { animation-delay: 0.15s; }

@keyframes badgeIn {
    from {
        opacity: 0;
        transform: translateY(6px) scale(0.8);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* Equation step sequential reveal */
.equation-step {
    opacity: 0;
    animation: stepReveal 0.4s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

@keyframes stepReveal {
    from {
        opacity: 0;
        transform: translateX(-12px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* Mol info item count-up appear */
.mol-info-item {
    animation: molInfoIn 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}

.mol-info-item:nth-child(1) { animation-delay: 0.05s; }
.mol-info-item:nth-child(2) { animation-delay: 0.1s; }
.mol-info-item:nth-child(3) { animation-delay: 0.15s; }
.mol-info-item:nth-child(4) { animation-delay: 0.2s; }
.mol-info-item:nth-child(5) { animation-delay: 0.25s; }
.mol-info-item:nth-child(6) { animation-delay: 0.3s; }

@keyframes molInfoIn {
    from {
        opacity: 0;
        transform: scale(0.85);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

/* Bond item animation */
.bond-item {
    animation: bondIn 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}

.bond-item:nth-child(1) { animation-delay: 0.1s; }
.bond-item:nth-child(2) { animation-delay: 0.15s; }
.bond-item:nth-child(3) { animation-delay: 0.2s; }
.bond-item:nth-child(4) { animation-delay: 0.25s; }

@keyframes bondIn {
    from {
        opacity: 0;
        transform: translateX(-8px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* Atom tooltip for 3D viewer */
.atom-tooltip {
    position: fixed;
    padding: 8px 14px;
    background: var(--card-bg);
    backdrop-filter: blur(12px) saturate(200%);
    -webkit-backdrop-filter: blur(12px) saturate(200%);
    border: 1px solid var(--card-border);
    border-radius: 10px;
    font-size: 0.78rem;
    color: var(--text-primary);
    pointer-events: none;
    z-index: 500;
    box-shadow: var(--shadow-md);
    animation: tooltipIn 0.2s ease;
    white-space: nowrap;
}

.atom-tooltip .tooltip-element {
    font-weight: 700;
    font-size: 0.9rem;
    margin-bottom: 2px;
}

.atom-tooltip .tooltip-name {
    color: var(--text-secondary);
    font-size: 0.72rem;
}

@keyframes tooltipIn {
    from {
        opacity: 0;
        transform: translateY(4px) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* 3D viewer hover highlight */
.viewer-3d-canvas canvas {
    cursor: grab;
}

.viewer-3d-canvas canvas:active {
    cursor: grabbing;
}

/* Nav tab click feedback */
.nav-tab {
    transition: transform 0.2s ease-out;
}

.nav-tab:hover {
    animation: elasticHover 0.5s cubic-bezier(0.2, 1.4, 0.4, 1) forwards;
}

.nav-tab:active {
    transform: scale(0.95);
    transition: transform 0.08s ease;
}

/* Suggestion item animation */
.suggestion-item {
    animation: suggestionSlide 0.2s ease both;
}

.suggestion-item:nth-child(1) { animation-delay: 0s; }
.suggestion-item:nth-child(2) { animation-delay: 0.03s; }
.suggestion-item:nth-child(3) { animation-delay: 0.06s; }
.suggestion-item:nth-child(4) { animation-delay: 0.09s; }
.suggestion-item:nth-child(5) { animation-delay: 0.12s; }
.suggestion-item:nth-child(6) { animation-delay: 0.15s; }

@keyframes suggestionSlide {
    from {
        opacity: 0;
        transform: translateY(-4px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Error message shake */
.error-message {
    animation: errorAppear 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes errorAppear {
    0% { opacity: 0; transform: scale(0.95); }
    40% { transform: scale(1.02); }
    100% { opacity: 1; transform: scale(1); }
}

/* Submit button loading state */
.primary-btn.loading {
    pointer-events: none;
    opacity: 0.7;
}

.primary-btn.loading::after {
    content: '';
    width: 16px;
    height: 16px;
    border: 2px solid transparent;
    border-top-color: white;
    border-radius: 50%;
    animation: btnSpin 0.6s linear infinite;
    margin-left: 8px;
    display: inline-block;
    vertical-align: middle;
}

@keyframes btnSpin {
    to { transform: rotate(360deg); }
}

/* Reaction display enhanced animations */
.reactant, .product {
    transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.reactant:hover, .product:hover {
    background: var(--tab-active-bg);
    transform: scale(1.05);
    box-shadow: var(--shadow-glow);
}

/* Search box focus expand */
.search-box {
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.search-box:focus-within {
    transform: scaleX(1.02);
    box-shadow: 0 0 0 3px var(--accent-light);
}

/* Toolbar btn press */
.toolbar-btn {
    transition: transform 0.2s ease-out;
}

.toolbar-btn:hover {
    animation: elasticHover 0.5s cubic-bezier(0.2, 1.4, 0.4, 1) forwards;
}

.toolbar-btn:active {
    transform: scale(0.9);
    transition: transform 0.08s ease;
}

/* View toggle active animation */
.viewer-ctrl-btn {
    transition: transform 0.2s ease-out;
}

.viewer-ctrl-btn:hover {
    animation: elasticHover 0.5s cubic-bezier(0.2, 1.4, 0.4, 1) forwards;
}

.viewer-ctrl-btn:active {
    transform: scale(0.9);
    transition: transform 0.08s ease;
}

.viewer-ctrl-btn.active {
    animation: ctrlActivate 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes ctrlActivate {
    0% { transform: scale(1); }
    50% { transform: scale(1.15); }
    100% { transform: scale(1); }
}

/* Smooth desc-block expand */
.desc-block {
    animation: descFadeIn 0.5s ease both;
}

@keyframes descFadeIn {
    from {
        opacity: 0;
        max-height: 0;
        padding-top: 0;
        padding-bottom: 0;
    }
    to {
        opacity: 1;
        max-height: 500px;
    }
}

/* Organic structure card enhanced */
.organic-structure {
    transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.organic-structure:hover {
    background: var(--tab-active-bg);
    transform: translateY(-2px);
    box-shadow: var(--shadow-glow);
}

/* Source badges */
.source-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 4px 10px;
    border-radius: 8px;
    font-size: 0.7rem;
    font-weight: 500;
    letter-spacing: 0.02em;
    margin-bottom: 12px;
}

.source-badge svg {
    flex-shrink: 0;
}

.source-icon {
    font-size: 0.8rem;
}

.source-local {
    background: rgba(52, 199, 89, 0.08);
    color: var(--success);
    border: 1px solid rgba(52, 199, 89, 0.15);
}

.source-parser {
    background: rgba(0, 122, 255, 0.08);
    color: var(--accent);
    border: 1px solid rgba(0, 122, 255, 0.15);
}

.source-inference {
    background: rgba(175, 82, 222, 0.08);
    color: #af52de;
    border: 1px solid rgba(175, 82, 222, 0.15);
}

.source-pubchem {
    background: rgba(255, 149, 0, 0.08);
    color: #ff9500;
    border: 1px solid rgba(255, 149, 0, 0.15);
}

.source-wikidata {
    background: rgba(0, 102, 255, 0.08);
    color: #0066ff;
    border: 1px solid rgba(0, 102, 255, 0.15);
}

.source-chemspider {
    background: rgba(52, 199, 89, 0.08);
    color: #34c759;
    border: 1px solid rgba(52, 199, 89, 0.15);
}

/* PubChem structure image */
.pubchem-structure-img {
    display: flex;
    justify-content: center;
    padding: 16px;
    margin-bottom: 16px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 14px;
    min-height: 180px;
    align-items: center;
}

.pubchem-structure-img img {
    max-width: 100%;
    max-height: 260px;
    border-radius: 8px;
    object-fit: contain;
    animation: structureFadeIn 0.5s ease;
}

@keyframes structureFadeIn {
    from { opacity: 0; transform: scale(0.95); }
    to { opacity: 1; transform: scale(1); }
}

/* PubChem CID link */
.pubchem-link {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    color: var(--accent);
    text-decoration: none;
    font-size: 0.78rem;
    font-weight: 500;
    transition: opacity 0.2s;
}

.pubchem-link:hover {
    opacity: 0.7;
}

/* PubChem loading state */
.pubchem-loading {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 16px 20px;
    background: var(--accent-light);
    border: 1px solid var(--accent-glow);
    border-radius: 12px;
    color: var(--accent);
    font-size: 0.85rem;
    animation: cardIn 0.3s ease;
}

.pubchem-loading .loading-spinner {
    width: 16px;
    height: 16px;
    border: 2px solid var(--accent-glow);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: btnSpin 0.6s linear infinite;
    flex-shrink: 0;
}