/* ===== CSS Reset & Base Styles ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Light Theme Colors */
    --primary-color: #1a365d;
    --secondary-color: #2563eb;
    --accent-color: #dc2626;
    --success-color: #059669;
    --warning-color: #d97706;
    --text-color: #1f2937;
    --text-light: #6b7280;
    --bg-color: #fafafa;
    --bg-gray: #f5f5f5;
    --bg-card: #ffffff;
    --border-color: #e0e0e0;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
    --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.08);

    /* Award Colors - Light Mode */
    --award-spotlight: #dc2626;
    --award-spotlight-bg: #fee2e2;
    --award-oral: #7c3aed;
    --award-oral-bg: #ede9fe;
    --award-best: #ea580c;
    --award-best-bg: #ffedd5;
    --award-poster: #059669;
    --award-poster-bg: #d1fae5;
    --award-default: #2563eb;
    --award-default-bg: #dbeafe;

    /* Selected Publication */
    --selected-border: #2563eb;
    --selected-bg: #f0f9ff;

    /* Typography */
    --font-main: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-mono: 'Courier New', Courier, monospace;

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

    /* Max Width */
    --max-width: 1200px;

    /* Transition */
    --transition-speed: 0.3s;
}

/* Dark Mode Colors */
[data-theme="dark"] {
    --primary-color: #60a5fa;
    --secondary-color: #3b82f6;
    --accent-color: #f87171;
    --success-color: #34d399;
    --warning-color: #fbbf24;
    --text-color: #f9fafb;
    --text-light: #d1d5db;
    --bg-color: #111827;
    --bg-gray: #1f2937;
    --bg-card: #1f2937;
    --border-color: #374151;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.4);

    /* Award Colors - Dark Mode */
    --award-spotlight: #fca5a5;
    --award-spotlight-bg: #7f1d1d;
    --award-oral: #c4b5fd;
    --award-oral-bg: #4c1d95;
    --award-best: #fdba74;
    --award-best-bg: #7c2d12;
    --award-poster: #6ee7b7;
    --award-poster-bg: #064e3b;
    --award-default: #93c5fd;
    --award-default-bg: #1e3a8a;

    /* Selected Publication */
    --selected-border: #60a5fa;
    --selected-bg: #1e3a8a;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    color: var(--text-color);
    line-height: 1.6;
    background-color: var(--bg-color);
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

a {
    color: var(--secondary-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.section {
    padding: var(--spacing-xl) 0;
}

.section-gray {
    background-color: var(--bg-gray);
}

.section-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
    color: var(--primary-color);
    border-bottom: 3px solid var(--secondary-color);
    padding-bottom: var(--spacing-xs);
    display: inline-block;
}

/* ===== Navigation ===== */
#navbar {
    background-color: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow);
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

#navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
}

.nav-brand h1 {
    font-size: 1.5rem;
    color: var(--primary-color);
    font-weight: 700;
}

.nav-right {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

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

.nav-link {
    color: var(--text-color);
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 4px;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.nav-link:hover {
    background-color: var(--bg-gray);
    color: var(--secondary-color);
}

/* Theme Picker & Toggle */
.theme-picker,
.theme-toggle {
    background: none;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    transition: all 0.3s ease;
    color: var(--text-color);
}

.theme-picker:hover,
.theme-toggle:hover {
    background-color: var(--bg-gray);
    transform: rotate(20deg);
}

/* ===== Hero Section ===== */
:root {
    --hero-gradient-start: #667eea;
    --hero-gradient-end: #764ba2;
}

[data-theme="dark"] {
    --hero-gradient-start: #1e3a8a;
    --hero-gradient-end: #581c87;
}

#hero {
    background: linear-gradient(135deg, var(--hero-gradient-start) 0%, var(--hero-gradient-end) 100%);
    color: white;
    padding: var(--spacing-xl) 0;
    min-height: 50vh;
    display: flex;
    align-items: center;
    transition: background 0.5s ease;
}

.hero-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-lg);
    text-align: center;
}

.hero-profile {
    display: flex;
    justify-content: center;
}

.profile-image {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    object-fit: cover;
    border: 5px solid rgba(255, 255, 255, 0.3);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
    transition: transform 0.3s ease;
}

.profile-image:hover {
    transform: scale(1.05);
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.hero-subtitle {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-xs);
    opacity: 0.95;
}

.hero-affiliation {
    font-size: 1.2rem;
    margin-bottom: var(--spacing-md);
    opacity: 0.9;
}

.hero-contact-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
}

.hero-contact {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.hero-email {
    display: flex;
    justify-content: center;
}

.contact-link {
    color: rgba(255, 255, 255, 0.95);
    font-weight: 600;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-bottom: 2px solid transparent;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
    font-size: 0.95rem;
}

.contact-link:hover {
    color: white;
    border-bottom-color: rgba(255, 255, 255, 0.9);
}

.contact-link.email-link {
    text-transform: none;
    letter-spacing: 0;
}

.separator {
    color: rgba(255, 255, 255, 0.5);
    font-weight: 300;
    padding: 0 var(--spacing-xs);
}

/* ===== About Section ===== */
.about-content {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: var(--spacing-lg);
    color: var(--text-color);
}

.about-content p {
    margin-bottom: var(--spacing-md);
}

.research-interests {
    margin-top: var(--spacing-lg);
}

.research-interests h3 {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
}

.interests-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-sm);
}

.interest-tag {
    background-color: var(--bg-gray);
    padding: var(--spacing-sm);
    border-radius: 8px;
    border-left: 4px solid var(--secondary-color);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.interest-tag:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow);
}

/* ===== News Section ===== */
.news-container {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    position: relative;
    padding-left: var(--spacing-md);
}

/* Timeline effect - minimal */
.news-container::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--border-color);
    border-radius: 1px;
}

.news-item {
    background-color: var(--bg-card);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: 6px;
    box-shadow: none;
    transition: all 0.2s ease;
    border-left: 2px solid var(--secondary-color);
    position: relative;
    display: flex;
    gap: var(--spacing-sm);
}

.news-item::before {
    content: '';
    position: absolute;
    left: calc(-1 * var(--spacing-md) - 5px);
    top: var(--spacing-sm);
    background-color: var(--secondary-color);
    border: 2px solid var(--bg-card);
    border-radius: 50%;
    width: 10px;
    height: 10px;
    box-shadow: 0 0 0 2px var(--border-color);
    transition: all 0.2s ease;
}

.news-item:hover {
    background-color: var(--bg-gray);
    transform: translateX(2px);
}

.news-item:hover::before {
    background-color: var(--accent-color);
    transform: scale(1.3);
}

.news-item-content {
    flex: 1;
}

.news-date {
    color: var(--text-light);
    font-size: 0.85rem;
    margin-bottom: 4px;
    font-weight: 600;
    letter-spacing: 0.3px;
}

.news-content {
    color: var(--text-color);
    line-height: 1.5;
    font-size: 0.95rem;
}

.news-content a {
    font-weight: 500;
    text-decoration: none;
    border-bottom: 1px solid var(--secondary-color);
}

.news-content a:hover {
    border-bottom-width: 2px;
}

.news-icon {
    font-size: 1.2rem;
    margin-right: 4px;
}

.news-toggle-container {
    display: flex;
    justify-content: center;
    margin-top: var(--spacing-md);
}

.news-toggle-btn {
    padding: var(--spacing-sm) var(--spacing-lg);
    background-color: var(--secondary-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.news-toggle-btn:hover {
    background-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.news-item.hidden {
    display: none;
}

/* ===== Publications Section ===== */
.publications-filter {
    display: flex;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
}

.filter-btn {
    padding: var(--spacing-xs) var(--spacing-md);
    background-color: var(--bg-gray);
    border: 2px solid var(--border-color);
    border-radius: 24px;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.3s ease;
    color: var(--text-color);
}

.filter-btn:hover {
    background-color: var(--secondary-color);
    color: white;
    border-color: var(--secondary-color);
}

.filter-btn.active {
    background-color: var(--secondary-color);
    color: white;
    border-color: var(--secondary-color);
}

.publications-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.publication-item {
    background-color: var(--selected-bg);
    padding: var(--spacing-md);
    border-radius: 8px;
    box-shadow: none;
    transition: all 0.2s ease;
    border: 1px solid var(--border-color);
    border-left: 3px solid var(--border-color);
    position: relative;
}

.publication-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    border-left-color: var(--secondary-color);
    background-color: var(--selected-bg);
}

.publication-item.selected {
    border-left: 3px solid var(--selected-border);
    background-color: var(--selected-bg);
    border-left-width: 4px;
}

.publication-item.selected:hover {
    box-shadow: 0 4px 16px rgba(37, 99, 235, 0.2);
}

.pub-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
}

.pub-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-color);
    flex: 1;
    line-height: 1.4;
}

.selected-badge {
    background-color: var(--selected-border);
    color: white;
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.3px;
    white-space: nowrap;
}

.pub-authors {
    color: var(--text-light);
    margin-bottom: 4px;
    font-size: 0.9rem;
    line-height: 1.5;
}

.author-link {
    color: var(--text-light);
    text-decoration: none;
    transition: color 0.2s ease;
}

.author-link:hover {
    color: var(--secondary-color);
    text-decoration: underline;
}

.pub-venue {
    color: var(--text-color);
    font-weight: 500;
    margin-bottom: var(--spacing-xs);
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

/* Award Badges with Different Colors */
.pub-award {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    margin-left: var(--spacing-xs);
    text-transform: uppercase;
    letter-spacing: 0.3px;
}

.pub-award.spotlight {
    background-color: var(--award-spotlight-bg);
    color: var(--award-spotlight);
    border: 1px solid var(--award-spotlight);
}

.pub-award.oral {
    background-color: var(--award-oral-bg);
    color: var(--award-oral);
    border: 1px solid var(--award-oral);
}

.pub-award.best {
    background-color: var(--award-best-bg);
    color: var(--award-best);
    border: 1px solid var(--award-best);
}

.pub-award.poster {
    background-color: var(--award-poster-bg);
    color: var(--award-poster);
    border: 1px solid var(--award-poster);
}

.pub-award.default {
    background-color: var(--award-default-bg);
    color: var(--award-default);
    border: 1px solid var(--award-default);
}

.pub-links {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
    margin-top: var(--spacing-xs);
}

.pub-link {
    padding: 4px 10px;
    background-color: var(--secondary-color);
    color: white;
    border-radius: 4px;
    font-size: 0.8rem;
    font-weight: 500;
    transition: all 0.2s ease;
    text-transform: uppercase;
    letter-spacing: 0.3px;
}

.pub-link:hover {
    background-color: var(--accent-color);
}

/* BibTeX Button */
.bibtex-btn {
    border: none;
    cursor: pointer;
    background-color: var(--text-light);
}

.bibtex-btn:hover {
    background-color: var(--text-color);
}

.bibtex-btn.copied {
    background-color: var(--success-color);
    pointer-events: none;
}

.bibtex-btn.copy-failed {
    background-color: var(--accent-color);
}

/* BibTeX Expanded Box */
.bibtex-box {
    margin-top: var(--spacing-md);
    padding: var(--spacing-md);
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    position: relative;
}

.bibtex-content {
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.85rem;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-gray);
    padding: var(--spacing-sm);
    border-radius: 4px;
    overflow-x: auto;
    margin: 0;
    white-space: pre-wrap;
    word-wrap: break-word;
    user-select: all;
    cursor: text;
}

/* Publication Keywords */
.pub-keywords {
    display: flex;
    flex-wrap: wrap;
    gap: 4px;
    margin-top: var(--spacing-xs);
    margin-bottom: var(--spacing-xs);
}

.pub-keyword {
    background-color: var(--bg-gray);
    color: var(--text-light);
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 500;
    border: 1px solid var(--border-color);
    transition: all 0.2s ease;
    cursor: default;
}

.pub-keyword::before {
    content: '#';
    margin-right: 2px;
    opacity: 0.6;
}

.pub-keyword:hover {
    background-color: var(--secondary-color);
    color: white;
    border-color: var(--secondary-color);
}

/* Author Links */
.author-link {
    color: inherit;
    text-decoration: none;
    border-bottom: 1px dotted var(--text-light);
    transition: all 0.2s ease;
}

.author-link:hover {
    color: var(--secondary-color);
    border-bottom-color: var(--secondary-color);
}

/* ===== Posts Section ===== */
.posts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: var(--spacing-lg);
}

.post-card {
    background-color: var(--bg-card);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    border: 1px solid var(--border-color);
}

.post-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
}

.post-header {
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--border-color);
}

.post-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
}

.post-date {
    color: var(--text-light);
    font-size: 0.9rem;
    font-weight: 600;
}

.post-category {
    background-color: var(--secondary-color);
    color: white;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
}

.post-title {
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: var(--spacing-sm);
    line-height: 1.3;
}

.post-content {
    padding: var(--spacing-md);
}

.post-excerpt {
    color: var(--text-light);
    line-height: 1.7;
    margin-bottom: var(--spacing-md);
}

.post-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
}

.post-tag {
    background-color: var(--bg-gray);
    color: var(--text-color);
    padding: 4px 10px;
    border-radius: 16px;
    font-size: 0.8rem;
    border: 1px solid var(--border-color);
}

.post-link {
    color: var(--secondary-color);
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 4px;
    transition: all 0.3s ease;
}

.post-link:hover {
    color: var(--accent-color);
    gap: 8px;
}

/* ===== Projects Section ===== */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.project-card {
    background-color: var(--bg-card);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    border: 1px solid var(--border-color);
}

.project-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
}

.project-content {
    padding: var(--spacing-md);
}

.project-title {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: var(--spacing-sm);
}

.project-description {
    color: var(--text-light);
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.project-category {
    display: inline-block;
    background-color: var(--secondary-color);
    color: white;
    padding: 4px 12px;
    border-radius: 4px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.project-links {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.project-link {
    padding: 6px 12px;
    background-color: var(--bg-gray);
    color: var(--secondary-color);
    border-radius: 4px;
    font-size: 0.9rem;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.project-link:hover {
    background-color: var(--secondary-color);
    color: white;
}

/* ===== Footer ===== */
.footer {
    background-color: var(--primary-color);
    color: white;
    padding: var(--spacing-lg) 0;
    text-align: center;
}

[data-theme="dark"] .footer {
    background-color: var(--bg-gray);
    border-top: 1px solid var(--border-color);
}

.footer p {
    margin-bottom: var(--spacing-xs);
}

.footer-note {
    font-size: 0.9rem;
    opacity: 0.8;
}

/* ===== Responsive Design ===== */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

    .nav-links {
        gap: var(--spacing-sm);
    }

    .nav-link {
        padding: var(--spacing-xs);
        font-size: 0.9rem;
    }

    .section-title {
        font-size: 1.5rem;
    }

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

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

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

@media (max-width: 480px) {
    .hero-title {
        font-size: 1.5rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .nav-right {
        gap: var(--spacing-sm);
    }

    .nav-links {
        flex-wrap: wrap;
        justify-content: center;
    }

    .hero-contact {
        flex-direction: column;
    }

    .separator {
        display: none;
    }

    .pub-header {
        flex-direction: column;
    }

    .selected-badge {
        align-self: flex-start;
    }
}

/* ===== Utility Classes ===== */
.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

.mb-1 {
    margin-bottom: var(--spacing-sm);
}

.mb-2 {
    margin-bottom: var(--spacing-md);
}

.mb-3 {
    margin-bottom: var(--spacing-lg);
}

/* ===== Theme Picker Modal ===== */
.theme-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 10000;
    backdrop-filter: blur(4px);
}

.theme-modal.hidden {
    display: none;
}

.theme-modal-content {
    background-color: var(--bg-card);
    border-radius: 16px;
    padding: var(--spacing-lg);
    max-width: 600px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
    border: 2px solid var(--border-color);
}

.theme-modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
    border-bottom: 2px solid var(--border-color);
    padding-bottom: var(--spacing-sm);
}

.theme-modal-header h3 {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin: 0;
}

.theme-modal-close {
    background: none;
    border: none;
    font-size: 2rem;
    cursor: pointer;
    color: var(--text-light);
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: all 0.3s ease;
}

.theme-modal-close:hover {
    background-color: var(--bg-gray);
    color: var(--accent-color);
    transform: rotate(90deg);
}

.theme-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
}

.theme-option {
    background-color: var(--bg-gray);
    border: 3px solid var(--border-color);
    border-radius: 12px;
    padding: var(--spacing-md);
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.theme-option:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
    border-color: var(--secondary-color);
}

.theme-option.active {
    border-color: var(--secondary-color);
    background-color: var(--selected-bg);
    box-shadow: 0 0 0 2px var(--secondary-color);
}

.theme-option-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
}

.theme-option-icon {
    font-size: 2rem;
}

.theme-option-name {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--primary-color);
}

.theme-option-description {
    font-size: 0.9rem;
    color: var(--text-light);
    line-height: 1.4;
}

.theme-option-preview {
    display: flex;
    gap: var(--spacing-xs);
    margin-top: var(--spacing-xs);
}

.theme-color-swatch {
    width: 30px;
    height: 30px;
    border-radius: 6px;
    border: 2px solid var(--border-color);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

/* ===== Smooth Transitions ===== */
* {
    transition-property: background-color, border-color, color;
    transition-duration: var(--transition-speed);
    transition-timing-function: ease;
}