/* ============================================================
   MyPersonalWeb — Light Space-Themed Academic Stylesheet
   ============================================================ */

/* -------------------------------------------------------
   1. CSS Variables
   ------------------------------------------------------- */
:root {
    /* Backgrounds */
    --bg-main: #F8FAFC;
    --bg-hero: #F1F5F9;
    --bg-card: #FFFFFF;

    /* Text */
    --text-primary: #1E293B;
    --text-secondary: #4B5563;

    /* Accents */
    --accent-blue: #3B82F6;
    --accent-indigo: #6366F1;
    --accent-cyan: #0891B2;

    /* Borders & Dividers */
    --border: #E2E8F0;
    --border-light: #F1F5F9;

    /* Glass */
    --glass-bg: rgba(255,255,255,0.8);

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
    --shadow-lg: 0 12px 24px rgba(0,0,0,0.1);
    --shadow-xl: 0 20px 48px rgba(0,0,0,0.12);

    /* Radii */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;

    /* Container */
    --container-max: 1200px;
    --section-padding: 6rem 1rem;

    /* Font */
    --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont,
                 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code',
                 'SF Mono', Consolas, monospace;
}

/* -------------------------------------------------------
   1b. Dark Mode Overrides
   ------------------------------------------------------- */
html.dark {
    --bg-main: #0F172A;
    --bg-hero: #1E293B;
    --bg-card: #1E293B;
    --text-primary: #F1F5F9;
    --text-secondary: #B0BEC5;
    --accent-blue: #60A5FA;
    --accent-indigo: #818CF8;
    --accent-cyan: #22D3EE;
    --border: #334155;
    --border-light: #1E293B;
    --glass-bg: rgba(30, 41, 59, 0.8);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 12px 24px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 20px 48px rgba(0, 0, 0, 0.6);
}

/* Explicit dark overrides for hardcoded colors in main.css */
html.dark .navbar {
    background: rgba(30, 41, 59, 0.75);
}
html.dark .paper-card .paper-links a {
    background: rgba(96, 165, 250, 0.1);
}
html.dark .navbar-links {
    background: rgba(30, 41, 59, 0.95);
}
html.dark .glass {
    background: rgba(30, 41, 59, 0.8);
}

/* WCAG AA: ensure Tailwind text-muted class has sufficient contrast in dark mode */
html.dark .text-muted {
    color: #B0BEC5;
}


/* Anchor offset for fixed navbar */
#research {
    scroll-margin-top: 80px;
}

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-main);
    color: var(--text-primary);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

img,
svg,
video,
canvas {
    display: block;
    max-width: 100%;
}

a {
    color: inherit;
    text-decoration: none;
}

button {
    font: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

ul, ol {
    list-style: none;
}

h1, h2, h3, h4, h5, h6 {
    line-height: 1.3;
    font-weight: 700;
    color: var(--text-primary);
}

p {
    color: var(--text-secondary);
}


/* -------------------------------------------------------
   3. Navigation (.navbar)
   ------------------------------------------------------- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 100;

    background: rgba(255,255,255,0.75);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    transition: background var(--transition-base);
}

.navbar-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.navbar-brand {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    white-space: nowrap;
}

.navbar-links {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.navbar-links a {
    position: relative;
    padding: 0.5rem 1rem;
    color: var(--text-secondary);
    font-size: 0.9375rem;
    font-weight: 500;
    border-radius: var(--radius-sm);
    transition: color var(--transition-fast),
                background var(--transition-fast);
}

.navbar-links a:hover {
    color: var(--accent-blue);
    background: rgba(59,130,246,0.06);
}

.navbar-links a.active {
    color: var(--accent-blue);
    font-weight: 600;
}

/* Language toggle */
.language-toggle {
    cursor: pointer;
    padding: 0.375rem 0.75rem;
    margin-left: 0.5rem;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    transition: opacity var(--transition-fast),
                background var(--transition-fast);
    border: 1px solid var(--border);
}

.language-toggle:hover {
    opacity: 0.8;
    background: rgba(59,130,246,0.06);
}

/* Mobile hamburger */
.hamburger {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 28px;
    height: 28px;
    cursor: pointer;
    z-index: 110;
}

.hamburger span {
    display: block;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: transform var(--transition-fast),
                opacity var(--transition-fast);
}

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

.hamburger.open span:nth-child(2) {
    opacity: 0;
}

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


/* -------------------------------------------------------
   4. Hero Section (.hero)
   ------------------------------------------------------- */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-hero);
    overflow: hidden;
}

.hero-canvas {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    padding: 2rem;
}

.hero-content .name {
    font-size: clamp(3rem, 8vw, 5rem);
    font-weight: 800;
    color: var(--text-primary);
    letter-spacing: -0.02em;
    line-height: 1.1;
    margin-bottom: 0.75rem;
}

.hero-content .subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    font-weight: 400;
    margin-bottom: 1.5rem;
}

.hero-content .hero-cta {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.75rem;
    background: var(--accent-blue);
    color: #fff;
    font-weight: 600;
    border-radius: 9999px;
    transition: background var(--transition-fast),
                transform var(--transition-fast),
                box-shadow var(--transition-fast);
}

.hero-content .hero-cta:hover {
    background: var(--accent-indigo);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* Scroll indicator */
.scroll-indicator {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    z-index: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.scroll-indicator span {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.scroll-indicator .arrow {
    width: 24px;
    height: 24px;
    border-right: 2px solid var(--text-secondary);
    border-bottom: 2px solid var(--text-secondary);
    transform: rotate(45deg);
    animation: bounce 2s infinite;
}


/* -------------------------------------------------------
   5. Research Cards (.research-card)
   ------------------------------------------------------- */
.research-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 1rem;
}

/* 防止研究方向卡片网格出现空槽位 — auto-fit 确保只创建足够容纳内容的列 */
.research-card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.research-card {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    padding: 1.75rem;
    transition: transform var(--transition-base),
                box-shadow var(--transition-base);
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

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

.research-card .card-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-hero);
    border-radius: var(--radius-md);
    font-size: 1.5rem;
    color: var(--accent-blue);
}

.research-card h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
}

.research-card p {
    font-size: 0.9375rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.research-card .card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.research-card .card-tags .tag {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background: var(--bg-hero);
    color: var(--accent-blue);
    font-size: 0.75rem;
    font-weight: 500;
    border-radius: 9999px;
    white-space: nowrap;
}

.research-card .card-footer {
    margin-top: auto;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--accent-blue);
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    transition: gap var(--transition-fast);
}

.research-card .card-footer:hover {
    gap: 0.625rem;
}


/* -------------------------------------------------------
   6. Paper Cards (.paper-card)
   ------------------------------------------------------- */
.papers-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 1rem;
}

.paper-card {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    border-left: 3px solid var(--accent-blue);
    box-shadow: var(--shadow-sm);
    padding: 1.75rem;
    transition: transform var(--transition-base),
                box-shadow var(--transition-base);
}

.paper-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.paper-card .paper-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    overflow-wrap: break-word;
    word-break: break-word;
}

.paper-card .paper-authors {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.paper-card .paper-venue {
    display: inline-block;
    font-size: 0.8125rem;
    color: var(--accent-cyan);
    font-weight: 500;
    margin-bottom: 1rem;
}

.paper-card .paper-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.paper-card .paper-links a {
    font-size: 0.875rem;
    color: var(--accent-blue);
    font-weight: 500;
    padding: 0.375rem 0.75rem;
    border-radius: var(--radius-sm);
    background: rgba(59,130,246,0.06);
    transition: background var(--transition-fast);
}

.paper-card .paper-links a:hover {
    background: rgba(59,130,246,0.12);
}

/* Abstract toggle */
.paper-card .abstract-toggle {
    font-size: 0.875rem;
    color: var(--accent-blue);
    cursor: pointer;
    font-weight: 500;
    padding: 0;
    text-align: left;
    margin-bottom: 0.5rem;
    transition: color var(--transition-fast);
}

.paper-card .abstract-toggle:hover {
    color: var(--accent-indigo);
}

.paper-card .abstract-content {
    overflow: hidden;
    max-height: 0;
    transition: max-height 0.4s ease,
                opacity 0.3s ease;
    opacity: 0;
}

.paper-card .abstract-content.open {
    max-height: 500px;
    opacity: 1;
}

.paper-card .abstract-text {
    font-size: 0.9375rem;
    color: var(--text-secondary);
    line-height: 1.7;
    padding: 0.75rem;
    background: var(--bg-hero);
    border-radius: var(--radius-sm);
    margin-bottom: 0.75rem;
}

/* BibTeX block */
.paper-card .bibtex-wrapper {
    position: relative;
    margin-top: 0.5rem;
}

.paper-card .bibtex-block {
    background: var(--bg-hero);
    border-radius: var(--radius-sm);
    padding: 1rem;
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    line-height: 1.6;
    color: var(--text-primary);
    overflow-x: auto;
    white-space: pre;
}

.paper-card .copy-btn {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    padding: 0.375rem 0.625rem;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-secondary);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.paper-card .copy-btn:hover {
    color: var(--accent-blue);
    border-color: var(--accent-blue);
}

.paper-card .copy-btn.copied {
    color: #10B981;
    border-color: #10B981;
}


/* -------------------------------------------------------
   7. Parallax Layers (.parallax-layer)
   ------------------------------------------------------- */
.parallax-layer {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: -1;
}

.parallax-layer .particle {
    position: absolute;
    border-radius: 50%;
    background: var(--accent-blue);
    opacity: 0.12;
}

.parallax-layer .particle.small {
    width: 2px;
    height: 2px;
}

.parallax-layer .particle.medium {
    width: 4px;
    height: 4px;
    opacity: 0.08;
}

.parallax-layer .particle.large {
    width: 6px;
    height: 6px;
    opacity: 0.06;
}


/* -------------------------------------------------------
   8. Section Styles
   ------------------------------------------------------- */
section {
    padding: var(--section-padding);
    position: relative;
}

.section-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    text-align: center;
    margin-bottom: 0.5rem;
}

.section-subtitle {
    font-size: 1.0625rem;
    color: var(--text-secondary);
    text-align: center;
    margin-bottom: 3rem;
    max-width: 640px;
    margin-left: auto;
    margin-right: auto;
}

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


/* -------------------------------------------------------
   9. Awards Timeline (.timeline)
   ------------------------------------------------------- */
.timeline {
    position: relative;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 1rem 0 2.5rem;
}

.timeline::before {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0.75rem;
    width: 2px;
    background: var(--border);
}

.timeline-item {
    position: relative;
    margin-bottom: 2rem;
    padding-left: 1.5rem;
}

.timeline-item:last-child {
    margin-bottom: 0;
}

.timeline-item::before {
    content: '';
    position: absolute;
    top: 0.5rem;
    left: -2rem;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--accent-blue);
    box-shadow: 0 0 0 4px var(--bg-main),
                0 0 0 5px var(--accent-blue);
    z-index: 1;
}

.timeline-item .timeline-card {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: 1.25rem 1.5rem;
    transition: transform var(--transition-base),
                box-shadow var(--transition-base);
}

.timeline-item .timeline-card:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
}

.timeline-item .timeline-year {
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--accent-blue);
    margin-bottom: 0.375rem;
}

.timeline-item .timeline-title {
    font-size: 1.0625rem;
    font-weight: 600;
    color: var(--text-primary);
}

.timeline-item .timeline-org {
    font-size: 0.875rem;
    color: var(--text-secondary);
}


/* -------------------------------------------------------
   10. Responsive
   ------------------------------------------------------- */

/* Tablet and below */
@media (max-width: 1024px) {
    .research-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Mobile */
@media (max-width: 768px) {
    :root {
        --section-padding: 4rem 1rem;
    }

    /* Mobile nav */
    .hamburger {
        display: flex;
    }

    .navbar-links {
        position: fixed;
        top: 0;
        right: 0;
        height: 100vh;
        width: 260px;
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
        padding: 5rem 1.5rem 2rem;
        background: rgba(255,255,255,0.95);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        border-left: 1px solid var(--border);
        transform: translateX(100%);
        transition: transform var(--transition-base);
        z-index: 105;
    }

    .navbar-links.open {
        transform: translateX(0);
    }

    .navbar-links a {
        width: 100%;
        font-size: 1.0625rem;
        padding: 0.625rem 0.75rem;
    }

    /* Dark mode mobile navbar */
    html.dark .navbar-links {
        background: rgba(15, 23, 42, 0.95);
    }

    .language-toggle {
        margin-left: 0;
        margin-top: 0.5rem;
        width: 100%;
        text-align: center;
    }

    /* Research grid → 1 column */
    .research-grid {
        grid-template-columns: 1fr;
    }

    /* Typography scaling */
    .section-title {
        font-size: 1.75rem;
    }

    .hero-content .subtitle {
        font-size: 1.0625rem;
    }

    /* Timeline mobile */
    .timeline {
        padding-left: 2rem;
    }

    .timeline::before {
        left: 0.5rem;
    }

    .timeline-item {
        padding-left: 1rem;
    }

    .timeline-item::before {
        left: -1.625rem;
    }
}

/* Small mobile */
@media (max-width: 480px) {
    .hero-content .name {
        font-size: 2.25rem;
    }

    .paper-card {
        padding: 1.25rem;
    }

    .navbar-container {
        padding: 0 1rem;
    }
}

/* Ultra-narrow mobile (≤375px) */
@media (max-width: 375px) {
    :root {
        --section-padding: 3rem 0.75rem;
    }

    /* Typography — ensure min 13px for readability */
    .scroll-indicator span {
        font-size: 0.8125rem;
    }

    .research-card .card-tags .tag {
        font-size: 0.8125rem;
    }

    .paper-card .copy-btn {
        font-size: 0.8125rem;
    }

    /* Navigation */
    .navbar-container {
        padding: 0 0.75rem;
    }

    .navbar-links {
        width: 100%;
    }

    .navbar-links a {
        font-size: 1rem;
    }

    /* Hero */
    .hero-content {
        padding: 1rem;
    }

    .hero-content .name {
        font-size: 1.75rem;
    }

    .hero-content .subtitle {
        font-size: 0.9375rem;
    }

    .hero-content .hero-cta {
        padding: 0.625rem 1.25rem;
        font-size: 0.875rem;
    }

    /* Section titles */
    .section-title {
        font-size: 1.5rem;
    }

    .section-subtitle {
        font-size: 0.9375rem;
        margin-bottom: 2rem;
        padding: 0 0.5rem;
    }

    /* Research cards */
    .research-card {
        padding: 1.25rem;
    }

    .research-card h3 {
        font-size: 1rem;
    }

    .research-card p {
        font-size: 0.875rem;
    }

    /* Paper cards */
    .paper-card {
        padding: 1rem;
    }

    .paper-card .paper-title {
        font-size: 1rem;
    }

    .paper-card .abstract-text {
        font-size: 0.875rem;
    }

    .paper-card .bibtex-block {
        font-size: 0.75rem;
        padding: 0.75rem;
    }

    /* Awards timeline */
    .timeline {
        padding-left: 1.5rem;
    }

    .timeline::before {
        left: 0.375rem;
    }

    .timeline-item {
        padding-left: 0.75rem;
    }

    .timeline-item::before {
        left: -1.25rem;
        width: 10px;
        height: 10px;
    }

    .timeline-item .timeline-card {
        padding: 1rem 1.125rem;
    }

    /* Contact */
    .contact-card {
        padding: 1.25rem;
    }

    /* Footer */
    .site-footer {
        padding: 1.5rem 0.75rem;
        font-size: 0.8125rem;
    }

    /* Tailwind utility overrides for ultra-narrow screens */
    section.py-20,
    section.py-16 {
        padding-top: 2.5rem;
        padding-bottom: 2.5rem;
    }
    section.py-12,
    section.py-10 {
        padding-top: 2rem;
        padding-bottom: 2rem;
    }
    section.py-6 {
        padding-top: 1rem;
        padding-bottom: 1rem;
    }
    .grid.gap-8 {
        gap: 1rem;
    }
    .grid.gap-10 {
        gap: 1.25rem;
    }
    .space-y-6 > :not([hidden]) ~ :not([hidden]) {
        --tw-space-y-reverse: 0;
        margin-top: 1rem;
    }
    .space-y-8 > :not([hidden]) ~ :not([hidden]) {
        --tw-space-y-reverse: 0;
        margin-top: 1.25rem;
    }
    .space-y-10 > :not([hidden]) ~ :not([hidden]) {
        --tw-space-y-reverse: 0;
        margin-top: 1.5rem;
    }
    .space-y-12 > :not([hidden]) ~ :not([hidden]) {
        --tw-space-y-reverse: 0;
        margin-top: 1.5rem;
    }
    .mb-14 {
        margin-bottom: 1.5rem;
    }
}


/* -------------------------------------------------------
   11. Animations
   ------------------------------------------------------- */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0) rotate(45deg);
    }
    40% {
        transform: translateY(-10px) rotate(45deg);
    }
    60% {
        transform: translateY(-5px) rotate(45deg);
    }
}

@keyframes float {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
}

@keyframes pulse {
    0%, 100% {
        opacity: 0.4;
    }
    50% {
        opacity: 0.7;
    }
}

.animate-in {
    animation: fadeInUp 0.6s ease both;
}

/* Staggered children */
.stagger > *:nth-child(1)  { animation-delay: 0.05s; }
.stagger > *:nth-child(2)  { animation-delay: 0.10s; }
.stagger > *:nth-child(3)  { animation-delay: 0.15s; }
.stagger > *:nth-child(4)  { animation-delay: 0.20s; }
.stagger > *:nth-child(5)  { animation-delay: 0.25s; }
.stagger > *:nth-child(6)  { animation-delay: 0.30s; }
.stagger > *:nth-child(7)  { animation-delay: 0.35s; }
.stagger > *:nth-child(8)  { animation-delay: 0.40s; }
.stagger > *:nth-child(9)  { animation-delay: 0.45s; }
.stagger > *:nth-child(10) { animation-delay: 0.50s; }
.stagger > *:nth-child(n+11) { animation-delay: 0.55s; }

/* -------------------------------------------------------
   11b. Research Card Scroll Reveal (S89)
   ------------------------------------------------------- */
.research-scroll-card {
    opacity: 0;
    transform: translateY(30px);
}

.research-scroll-card.reveal {
    animation: fadeInUp 0.6s ease forwards;
}


/* -------------------------------------------------------
   12. Utility Classes
   ------------------------------------------------------- */
.text-gradient {
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-indigo));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.glass {
    background: rgba(255,255,255,0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(226,232,240,0.6);
    border-radius: var(--radius-lg);
}

.section-divider {
    height: 1px;
    max-width: var(--container-max);
    margin: 0 auto;
    background: linear-gradient(
        90deg,
        transparent,
        var(--border) 20%,
        var(--border) 80%,
        transparent
    );
}

/* Accessibility: reduced motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}


/* -------------------------------------------------------
   Additional Section-Specific Helpers
   ------------------------------------------------------- */

/* ===== N5: Enhanced research card progress bars ===== */
/* Increase height from 6px to 10px, add more rounded corners */
div[class*="h-1.5"] {
    height: 10px !important;
}
div[class*="h-1.5"] > div {
    border-radius: 8px !important;
}

/* ===== N6: About page bio paragraph — increased line-height ===== */
p[data-i18n="about.bio_text"] {
    line-height: 1.85 !important;
}

/* About section */
.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 1rem;
    align-items: center;
}

.about-image {
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.about-text h2 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
}

.about-text p {
    margin-bottom: 1rem;
}

@media (max-width: 768px) {
    .about-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}

/* Contact section */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 1rem;
}

.contact-card {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    padding: 1.75rem;
    text-align: center;
    transition: transform var(--transition-base),
                box-shadow var(--transition-base);
}

.contact-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.contact-card .contact-icon {
    font-size: 1.75rem;
    color: var(--accent-blue);
    margin-bottom: 0.75rem;
}

.contact-card h3 {
    font-size: 1rem;
    margin-bottom: 0.375rem;
}

.contact-card p,
.contact-card a {
    font-size: 0.9375rem;
    color: var(--text-secondary);
}

.contact-card a:hover {
    color: var(--accent-blue);
}

/* ============================================================
   Blog TOC Sidebar — Collapsible (Left Side)
   ============================================================ */

/* Toggle button: small circle that sits on the right edge of the sidebar */
.blog-toc-toggle-btn {
    position: absolute;
    top: 0.75rem;
    right: -1.25rem;
    z-index: 20;
    width: 2rem;
    height: 2rem;
    border-radius: 50%;
    border: 1px solid var(--border);
    background: var(--bg-card);
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-fast);
    padding: 0;
    line-height: 1;
}

.blog-toc-toggle-btn:hover {
    background: var(--accent-blue);
    color: #fff;
    border-color: var(--accent-blue);
    box-shadow: var(--shadow-md);
}

.blog-toc-toggle-icon {
    display: inline-block;
    transition: transform var(--transition-base);
}

/* The sticky div itself creates a positioning context for the absolute toggle button.
   No position override needed — sticky elements create containing blocks. */

/* Collapsed sidebar: shrink to just enough space for the toggle button */
#blog-toc-sidebar.blog-toc-collapsed {
    width: 0 !important;
    min-width: 0 !important;
}

/* Collapsed: hide the nav */
#blog-toc-sidebar.blog-toc-collapsed .blog-toc-nav {
    display: none;
}

/* When TOC is collapsed, center the main content */
/* Note: main content uses `mx-auto` by default (set in template), so it's always centered */

/* Smooth transitions on the nav + scrollable when TOC is too tall */
.blog-toc-nav {
    transition: opacity var(--transition-base), transform var(--transition-base);
    max-height: calc(100vh - 12rem);
    overflow-y: auto;
    /* Firefox custom scrollbar */
    scrollbar-width: thin;
    scrollbar-color: var(--border) transparent;
}

/* Webkit custom scrollbar for blog-toc-nav */
.blog-toc-nav::-webkit-scrollbar {
    width: 5px;
}
.blog-toc-nav::-webkit-scrollbar-track {
    background: transparent;
}
.blog-toc-nav::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 10px;
}
.blog-toc-nav::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted, #B0BEC5);
}

/* Desktop TOC links */
#blog-toc-list .blog-toc-link {
    display: block;
    padding: 0.35rem 0.5rem;
    border-radius: 0.375rem;
    font-size: 0.8125rem;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all var(--transition-fast);
}
#blog-toc-list .blog-toc-link:hover {
    color: var(--accent-blue);
    background: rgba(59, 130, 246, 0.06);
}
#blog-toc-list .blog-toc-link.toc-active {
    color: var(--accent-blue);
    background: rgba(59, 130, 246, 0.08);
    font-weight: 500;
}
#blog-toc-list .blog-toc-link.toc-h3 {
    padding-left: 1.25rem;
    font-size: 0.75rem;
}

/* ============================================================
   Mobile TOC — Floating Button + Slide-in Drawer
   ============================================================ */

/* Floating TOC button for narrow screens (< 1024px) */
.blog-toc-mobile-btn {
    position: fixed;
    /* Stagger above the back-to-top button (bottom: 32px, h: 44px) + 12px gap */
    bottom: 88px;
    right: 1.5rem;
    z-index: 40;
    width: 3rem;
    height: 3rem;
    border-radius: 50%;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.12);
    transition: all var(--transition-fast);
    padding: 0;
}

.blog-toc-mobile-btn:hover {
    background: var(--accent-blue);
    color: #fff;
    border-color: var(--accent-blue);
    box-shadow: 0 6px 20px rgba(59, 130, 246, 0.3);
}

/* Tighter button spacing on mobile to avoid overflow issues */
@media (max-width: 640px) {
    .blog-toc-mobile-btn {
        right: 1rem;
        bottom: 80px;
    }
}

/* Overlay backdrop */
.blog-toc-mobile-overlay {
    position: fixed;
    inset: 0;
    z-index: 50;
    background: rgba(0, 0, 0, 0.4);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.blog-toc-mobile-overlay.open {
    opacity: 1;
    pointer-events: auto;
}

/* Slide-in drawer from the left */
.blog-toc-mobile-drawer {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: 80vw;
    max-width: 320px;
    z-index: 51;
    background: var(--surface);
    padding: 1.5rem;
    overflow-y: auto;
    box-shadow: 4px 0 24px rgba(0, 0, 0, 0.15);
    transform: translateX(-100%);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.blog-toc-mobile-overlay.open .blog-toc-mobile-drawer {
    transform: translateX(0);
}

/* Mobile TOC links — same styling as desktop */
#blog-toc-mobile-list .blog-toc-link {
    display: block;
    padding: 0.35rem 0.5rem;
    font-size: 0.8125rem;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: 0.375rem;
    transition: all var(--transition-fast);
    border-left: 2px solid transparent;
}

#blog-toc-mobile-list .blog-toc-link:hover {
    color: var(--accent-blue);
    background: rgba(59, 130, 246, 0.06);
    border-left-color: var(--accent-blue);
}

#blog-toc-mobile-list .blog-toc-link.toc-active {
    color: var(--accent-blue);
    background: rgba(59, 130, 246, 0.08);
    border-left-color: var(--accent-blue);
    font-weight: 500;
}

#blog-toc-mobile-list .blog-toc-link.toc-h3 {
    padding-left: 1.25rem;
    font-size: 0.75rem;
}

/* Footer */
.site-footer {
    text-align: center;
    padding: 2rem 1rem;
    border-top: 1px solid var(--border);
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* ============================================================
   Hobbies Carousel (S3)
   ============================================================ */

/* Carousel container — hide overflow for sliding effect */
.hobbies-carousel {
    overflow: hidden;
}

/* Track — holds all slides in a row */
.hobbies-carousel-track {
    display: flex;
    transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Individual slide */
.hobbies-carousel-slide {
    width: 100%;
    flex-shrink: 0;
}

/* Arrow buttons */
.carousel-arrow {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    z-index: 10;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--bg-card);
    border: 1px solid var(--border);
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.10);
    transition: all 0.3s ease;
}
.carousel-arrow:hover {
    background: var(--accent-blue);
    color: #fff;
    border-color: var(--accent-blue);
    box-shadow: 0 4px 16px rgba(59, 130, 246, 0.25);
}
.carousel-arrow-left {
    left: 4px;
}
.carousel-arrow-right {
    right: 4px;
}

/* Dot indicators — enhanced size + active state */
.carousel-dots {
    display: flex;
    justify-content: center;
    gap: 12px;
    margin-top: 24px;
}
.carousel-dot {
    width: 14px;
    height: 14px;
    border-radius: 50%;
    border: 2px solid var(--border);
    background: transparent;
    cursor: pointer;
    padding: 0;
    transition: all 0.3s ease;
}
.carousel-dot:hover {
    border-color: var(--accent-blue);
    background: var(--accent-blue);
    opacity: 0.6;
}
.carousel-dot.active {
    background: var(--accent-blue);
    border-color: var(--accent-blue);
    transform: scale(1.2);
    box-shadow: 0 0 8px rgba(59, 130, 246, 0.4);
}

/* Dark mode arrow and dot overrides */
html.dark .carousel-arrow {
    background: var(--surface);
    border-color: var(--border);
    color: #F1F5F9;
}
html.dark .carousel-arrow:hover {
    background: var(--accent-blue);
    color: #fff;
}
html.dark .carousel-dot {
    border-color: var(--border);
}
html.dark .carousel-dot.active {
    background: var(--accent-blue);
    border-color: var(--accent-blue);
}

/* Arrow positioning on narrow screens */
@media (max-width: 768px) {
    .carousel-arrow-left {
        left: 0;
    }
    .carousel-arrow-right {
        right: 0;
    }
    .carousel-arrow {
        width: 40px;
        height: 40px;
    }
    .carousel-dot {
        width: 12px;
        height: 12px;
    }
}

/* ============================================================
   Page fade-in animation (N37)
   ============================================================ */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ============================================================
   Back-to-Top Button — Pulse Animation & Tooltip (S59)
   ============================================================ */
@keyframes backToTopPulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.12);
    }
}

[data-back-to-top].is-visible {
    animation: backToTopPulse 2.2s ease-in-out infinite;
}

/* Tooltip on hover */
[data-back-to-top]::after {
    content: attr(data-tooltip);
    position: absolute;
    right: 56px;
    top: 50%;
    transform: translateY(-50%);
    background: var(--accent);
    color: white;
    padding: 5px 12px;
    border-radius: 6px;
    font-size: 13px;
    font-weight: 500;
    white-space: nowrap;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s ease;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

[data-back-to-top]::before {
    content: '';
    position: absolute;
    right: 50px;
    top: 50%;
    transform: translateY(-50%);
    border: 6px solid transparent;
    border-left-color: var(--accent);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s ease;
}

[data-back-to-top]:hover::after,
[data-back-to-top]:hover::before {
    opacity: 1;
}

.page-content {
    animation: fadeIn 0.4s ease-out;
}

/* Page fade-out for navigation transitions */
@keyframes fadeOut {
    from { opacity: 1; transform: translateY(0); }
    to   { opacity: 0; transform: translateY(-8px); }
}
.page-fade-out {
    animation: fadeOut 0.2s ease-in forwards;
}

/* Disable page transition animations when no-transition is active (theme FOUC guard) */
html.no-transition .page-content {
    animation: none;
}
html.no-transition .page-fade-out {
    animation: none;
}