/* ============================================
   CSS Variables - Neo-Tang Color Palette
   ============================================ */
:root {
    --cinnabar: #8B2E2E;
    --cinnabar-dark: #6B1E1E;
    --cinnabar-light: #A84444;
    --ink: #1A1A1A;
    --ink-medium: #2A2A2A;
    --rice-paper: #F5F1E8;
    --rice-paper-dark: #E8E1D3;
    --gold: #D4AF37;
    --gold-muted: #B8984F;
    --jade: #7C9D96;
    --jade-light: #9CB5AD;
    --text-primary: #1A1A1A;
    --text-secondary: #4A4A4A;
    --text-light: #6A6A6A;

    --font-display: 'Playfair Display', serif;
    --font-serif: 'Crimson Pro', serif;
    --font-chinese: 'Noto Serif SC', serif;

    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 3rem;
    --spacing-xl: 5rem;

    --border-radius: 4px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

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

/* ============================================
   Texture Overlay
   ============================================ */
.texture-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image:
        repeating-linear-gradient(
            0deg,
            transparent,
            transparent 2px,
            rgba(0, 0, 0, 0.01) 2px,
            rgba(0, 0, 0, 0.01) 4px
        ),
        repeating-linear-gradient(
            90deg,
            transparent,
            transparent 2px,
            rgba(0, 0, 0, 0.01) 2px,
            rgba(0, 0, 0, 0.01) 4px
        );
    pointer-events: none;
    z-index: 1;
    opacity: 0.4;
}

/* ============================================
   Seal Decorations
   ============================================ */
.seal-decoration {
    width: 80px;
    height: 80px;
    background: var(--cinnabar);
    opacity: 0.08;
    position: absolute;
    transform: rotate(45deg);
    border: 2px solid var(--cinnabar);
}

.seal-top {
    top: 5%;
    right: 10%;
    animation: sealFade 1.5s ease-out 0.8s backwards;
}

.seal-about {
    top: -30px;
    left: -30px;
    width: 100px;
    height: 100px;
    opacity: 0.06;
}

@keyframes sealFade {
    from {
        opacity: 0;
        transform: rotate(45deg) scale(0.5);
    }
    to {
        opacity: 0.08;
        transform: rotate(45deg) scale(1);
    }
}

/* ============================================
   Container
   ============================================ */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    position: relative;
    z-index: 2;
}

/* ============================================
   Split Hero Section
   ============================================ */
.split-hero {
    min-height: 100vh;
    display: grid;
    grid-template-columns: 45% 55%;
    position: relative;
    z-index: 2;
}

.hero-side {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-lg);
    background: linear-gradient(
        135deg,
        var(--rice-paper) 0%,
        var(--rice-paper-dark) 100%
    );
    border-right: 1px solid rgba(139, 46, 46, 0.1);
    position: relative;
}

.vertical-title {
    display: flex;
    flex-direction: column;
    font-family: var(--font-chinese);
    font-size: 5rem;
    font-weight: 700;
    color: var(--cinnabar);
    writing-mode: vertical-rl;
    text-orientation: upright;
    letter-spacing: 0.2em;
    line-height: 1;
    margin-bottom: var(--spacing-lg);
}

.title-character {
    display: inline-block;
    animation: titleReveal 0.8s cubic-bezier(0.4, 0, 0.2, 1) backwards;
    transition: var(--transition);
}

.title-character:hover {
    color: var(--gold);
    transform: scale(1.1);
}

@keyframes titleReveal {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.hero-text {
    max-width: 500px;
    text-align: center;
    animation: fadeInUp 1s ease-out 0.5s backwards;
}

.main-title {
    font-family: var(--font-display);
    font-size: 2.8rem;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
    color: var(--ink);
    letter-spacing: -0.02em;
}

.subtitle {
    font-size: 1.3rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
    font-style: italic;
}

.tagline {
    font-size: 0.95rem;
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-weight: 400;
}

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

/* ============================================
   Converter Side
   ============================================ */
.converter-side {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-lg);
    background: white;
}

.converter-container {
    width: 100%;
    max-width: 600px;
}

.converter-header {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.converter-header h2 {
    font-family: var(--font-display);
    font-size: 2.2rem;
    color: var(--cinnabar);
    margin-bottom: var(--spacing-xs);
}

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

.input-panel, .output-panel {
    background: var(--rice-paper);
    border: 1px solid rgba(139, 46, 46, 0.15);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
    transition: var(--transition);
}

.input-panel:hover, .output-panel:hover {
    border-color: var(--cinnabar-light);
    box-shadow: 0 4px 16px rgba(139, 46, 46, 0.08);
}

.input-label {
    display: block;
    font-family: var(--font-serif);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--cinnabar);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-xs);
}

textarea {
    width: 100%;
    padding: var(--spacing-sm);
    border: 2px solid rgba(139, 46, 46, 0.2);
    border-radius: var(--border-radius);
    font-family: var(--font-chinese);
    font-size: 1.2rem;
    line-height: 1.8;
    resize: vertical;
    transition: var(--transition);
    background: white;
}

textarea:focus {
    outline: none;
    border-color: var(--cinnabar);
    box-shadow: 0 0 0 3px rgba(139, 46, 46, 0.1);
}

.input-panel .btn-primary {
    margin-top: var(--spacing-sm);
    width: 100%;
    justify-content: center;
}

/* Buttons */
.btn-primary, .btn-secondary {
    padding: var(--spacing-sm) var(--spacing-md);
    border: none;
    border-radius: var(--border-radius);
    font-family: var(--font-serif);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.btn-primary {
    background: var(--cinnabar);
    color: white;
    box-shadow: 0 4px 12px rgba(139, 46, 46, 0.3);
}

.btn-primary:hover {
    background: var(--cinnabar-dark);
    box-shadow: 0 6px 16px rgba(139, 46, 46, 0.4);
    transform: translateY(-2px);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background: transparent;
    color: var(--cinnabar);
    border: 2px solid var(--cinnabar);
}

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

.copy-btn {
    width: 100%;
    margin-top: var(--spacing-sm);
    justify-content: center;
}

.copy-btn.copied {
    background: var(--jade);
    border-color: var(--jade);
    color: white;
}

/* Output Panel */
.output-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
}

.status-indicator {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.85rem;
    color: var(--text-secondary);
}

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

.status-indicator.processing .status-dot {
    background: var(--gold);
}

.status-indicator.error .status-dot {
    background: var(--cinnabar);
    animation: none;
}

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

.ipa-display {
    min-height: 120px;
    padding: var(--spacing-md);
    background: white;
    border: 1px solid rgba(139, 46, 46, 0.1);
    border-radius: var(--border-radius);
    font-family: 'Courier New', monospace;
    font-size: 1.05rem;
    line-height: 1.8;
    color: var(--ink);
    word-break: break-word;
    overflow-wrap: break-word;
    overflow-x: auto;
}

.ipa-display pre {
    margin: 0;
    white-space: pre-wrap;
    word-wrap: break-word;
    font-family: inherit;
}

.placeholder-text {
    color: var(--text-light);
    font-style: italic;
    font-family: var(--font-serif);
}

.audio-player {
    margin-top: var(--spacing-md);
    padding: var(--spacing-md);
    background: white;
    border-radius: var(--border-radius);
    border: 2px solid var(--cinnabar-light);
}

.audio-player.hidden {
    display: none;
}

audio {
    width: 100%;
    margin-bottom: var(--spacing-sm);
}

/* ============================================
   Sections
   ============================================ */
section {
    padding: var(--spacing-xl) 0;
    position: relative;
    z-index: 2;
}

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

.section-header h2 {
    font-family: var(--font-display);
    font-size: 2.5rem;
    color: var(--cinnabar);
    margin-bottom: var(--spacing-sm);
    position: relative;
    display: inline-block;
}

.section-header h2::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 2px;
    background: var(--gold);
}

.section-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    font-style: italic;
}

/* ============================================
   Examples Carousel
   ============================================ */
.examples {
    background: white;
}

.carousel {
    position: relative;
    margin: var(--spacing-lg) 0;
    padding: 0 60px;
}

.carousel-track {
    display: flex;
    gap: var(--spacing-md);
    overflow-x: auto;
    scroll-behavior: smooth;
    scrollbar-width: none;
    -ms-overflow-style: none;
}

.carousel-track::-webkit-scrollbar {
    display: none;
}

.poem-card {
    flex: 0 0 350px;
    background: var(--rice-paper);
    border: 2px solid rgba(139, 46, 46, 0.15);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
    cursor: pointer;
    transition: var(--transition);
    position: relative;
}

.poem-card::before {
    content: '';
    position: absolute;
    top: 10px;
    right: 10px;
    width: 40px;
    height: 40px;
    background: var(--cinnabar);
    opacity: 0.05;
    transform: rotate(45deg);
}

.poem-card:hover {
    border-color: var(--cinnabar);
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(139, 46, 46, 0.15);
}

.poem-title {
    font-family: var(--font-display);
    font-size: 1.4rem;
    color: var(--cinnabar);
    margin-bottom: var(--spacing-xs);
}

.poem-author {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    font-style: italic;
}

.poem-text {
    font-family: var(--font-chinese);
    font-size: 1.1rem;
    line-height: 2;
    color: var(--ink);
    writing-mode: vertical-rl;
    text-orientation: upright;
    height: 200px;
    letter-spacing: 0.1em;
}

.carousel-btn {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: 2px solid var(--cinnabar);
    background: white;
    color: var(--cinnabar);
    font-size: 1.5rem;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10;
}

.carousel-btn:hover {
    background: var(--cinnabar);
    color: white;
    transform: translateY(-50%) scale(1.1);
}

.carousel-prev {
    left: 0;
}

.carousel-next {
    right: 0;
}

.carousel-dots {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xs);
    margin-top: var(--spacing-md);
}

.dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: rgba(139, 46, 46, 0.2);
    cursor: pointer;
    transition: var(--transition);
}

.dot.active {
    background: var(--cinnabar);
    transform: scale(1.2);
}

/* ============================================
   About Section
   ============================================ */
.about {
    background: linear-gradient(
        135deg,
        var(--rice-paper) 0%,
        var(--rice-paper-dark) 100%
    );
}

.about-grid {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: var(--spacing-xl);
    align-items: start;
}

.about-content {
    position: relative;
}

.about-content h2 {
    font-family: var(--font-display);
    font-size: 2.5rem;
    color: var(--cinnabar);
    margin-bottom: var(--spacing-md);
}

.lead {
    font-size: 1.3rem;
    line-height: 1.7;
    color: var(--ink);
    margin-bottom: var(--spacing-md);
    font-weight: 600;
}

.about-content p {
    margin-bottom: var(--spacing-md);
    font-size: 1.05rem;
    line-height: 1.8;
    color: var(--text-secondary);
}

/* Phonology Showcase */
.phonology-showcase {
    background: white;
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    border: 2px solid rgba(139, 46, 46, 0.15);
    position: sticky;
    top: var(--spacing-md);
}

.phonology-showcase h3 {
    font-family: var(--font-display);
    font-size: 1.4rem;
    color: var(--cinnabar);
    margin-bottom: var(--spacing-md);
    text-align: center;
}

.phonology-intro {
    font-size: 0.95rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-sm);
    background: var(--rice-paper);
    border-left: 3px solid var(--cinnabar-light);
    border-radius: var(--border-radius);
}

/* Process Steps */
.process-steps {
    margin: var(--spacing-md) 0 var(--spacing-lg);
}

.process-step {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-sm);
    background: var(--rice-paper);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.process-step:hover {
    background: rgba(212, 175, 55, 0.05);
    transform: translateX(4px);
}

.step-number {
    flex-shrink: 0;
    width: 36px;
    height: 36px;
    background: var(--cinnabar);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-display);
    font-weight: 600;
    font-size: 1.1rem;
}

.step-content h4 {
    font-family: var(--font-display);
    font-size: 1.05rem;
    color: var(--cinnabar-dark);
    margin-bottom: 0.4rem;
}

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

.phoneme-grid {
    display: grid;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.phoneme-item {
    display: grid;
    grid-template-columns: 80px 1fr;
    align-items: start;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    background: var(--rice-paper);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.phoneme-item:hover {
    background: var(--rice-paper-dark);
    transform: translateX(4px);
}

.phoneme-ipa {
    font-family: 'Courier New', monospace;
    font-size: 1.2rem;
    font-weight: bold;
    color: var(--cinnabar);
    text-align: center;
    padding-top: 2px;
}

.phoneme-desc {
    font-size: 0.88rem;
    line-height: 1.6;
    color: var(--text-secondary);
}

/* Learn More Section */
.learn-more {
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-md);
    border-top: 2px solid rgba(139, 46, 46, 0.1);
}

.learn-more h4 {
    font-family: var(--font-display);
    font-size: 1.1rem;
    color: var(--cinnabar);
    margin-bottom: var(--spacing-sm);
    text-align: center;
}

.resource-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.resource-list li {
    margin-bottom: var(--spacing-sm);
}

.resource-list a {
    display: block;
    padding: var(--spacing-xs) var(--spacing-sm);
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.85rem;
    line-height: 1.6;
    border-radius: var(--border-radius);
    transition: var(--transition);
    border-left: 2px solid transparent;
}

.resource-list a:hover {
    background: var(--rice-paper);
    border-left-color: var(--cinnabar);
    color: var(--ink);
    transform: translateX(4px);
}

.resource-list strong {
    color: var(--cinnabar-dark);
    font-weight: 600;
    display: block;
    margin-bottom: 2px;
}

/* ============================================
   Footer
   ============================================ */
.footer {
    background: var(--ink);
    color: var(--rice-paper);
    padding: var(--spacing-md) 0;
    text-align: center;
    position: relative;
    z-index: 2;
}

.copyright {
    font-size: 0.9rem;
    opacity: 0.7;
    font-family: var(--font-display);
    letter-spacing: 0.05em;
}

.copyright a {
    color: inherit;
    text-decoration: none;
    transition: var(--transition);
}

.copyright a:hover {
    opacity: 1;
    color: var(--gold);
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 968px) {
    .split-hero {
        grid-template-columns: 1fr;
        min-height: auto;
    }

    .hero-side {
        padding: var(--spacing-lg) var(--spacing-md);
        border-right: none;
        border-bottom: 1px solid rgba(139, 46, 46, 0.1);
    }

    .converter-side {
        padding: var(--spacing-lg) var(--spacing-md);
    }

    .vertical-title {
        writing-mode: horizontal-tb;
        flex-direction: row;
        font-size: 4rem;
        margin-bottom: var(--spacing-md);
    }

    .main-title {
        font-size: 2.2rem;
    }

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

    .carousel {
        padding: 0 40px;
    }

    .poem-text {
        writing-mode: horizontal-tb;
        text-orientation: mixed;
        height: auto;
    }
}

@media (max-width: 640px) {
    :root {
        --spacing-lg: 2rem;
        --spacing-xl: 3rem;
    }

    .vertical-title {
        font-size: 3rem;
    }

    .main-title {
        font-size: 1.8rem;
    }

    .subtitle {
        font-size: 1.1rem;
    }

    .section-header h2 {
        font-size: 2rem;
    }

    .carousel {
        padding: 0 20px;
    }

    .carousel-btn {
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }
}