/* ===== CSS Variables / Themes ===== */
:root {
    --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
    --font-serif: 'Playfair Display', Georgia, serif;
    --max-width: 1200px;
    --radius: 12px;
    --radius-sm: 8px;
    --transition: 0.3s ease;
}

[data-theme="dark"] {
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-card: #1a1a26;
    --bg-card-hover: #22222f;
    --bg-nav: rgba(10, 10, 15, 0.85);
    --text-primary: #f0f0f5;
    --text-secondary: #a0a0b5;
    --text-muted: #6a6a80;
    --accent: #c8a24e;
    --accent-hover: #dab55e;
    --accent-subtle: rgba(200, 162, 78, 0.12);
    --border: #2a2a3a;
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
    --shadow-card: 0 2px 12px rgba(0, 0, 0, 0.3);
    --hero-gradient: linear-gradient(135deg, #0a0a0f 0%, #1a1028 50%, #0a0a0f 100%);
    --input-bg: #1a1a26;
}

[data-theme="light"] {
    --bg-primary: #fafaf8;
    --bg-secondary: #f0efe8;
    --bg-card: #ffffff;
    --bg-card-hover: #f8f7f2;
    --bg-nav: rgba(250, 250, 248, 0.9);
    --text-primary: #1a1a1a;
    --text-secondary: #555555;
    --text-muted: #888888;
    --accent: #8b6914;
    --accent-hover: #a07a1a;
    --accent-subtle: rgba(139, 105, 20, 0.08);
    --border: #e0ddd5;
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.08);
    --shadow-card: 0 2px 12px rgba(0, 0, 0, 0.06);
    --hero-gradient: linear-gradient(135deg, #fafaf8 0%, #f0e8d8 50%, #fafaf8 100%);
    --input-bg: #ffffff;
}

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

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

body {
    font-family: var(--font-sans);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    transition: background-color var(--transition), color var(--transition);
    overflow-x: hidden;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    text-decoration: none;
    color: var(--accent);
    transition: color var(--transition);
}

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

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

/* ===== Navbar ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: var(--bg-nav);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: background var(--transition), border var(--transition);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-family: var(--font-serif);
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.logo-icon {
    font-size: 1.5rem;
    color: var(--accent);
}

.nav-links {
    display: flex;
    align-items: center;
    list-style: none;
    gap: 8px;
}

.nav-links a {
    color: var(--text-secondary);
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 500;
    transition: color var(--transition), background var(--transition);
}

.nav-links a:hover {
    color: var(--text-primary);
    background: var(--accent-subtle);
}

.btn-icon {
    background: none;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 6px 10px;
    cursor: pointer;
    font-size: 1rem;
    line-height: 1;
    transition: all var(--transition);
}

.btn-icon:hover {
    border-color: var(--accent);
    background: var(--accent-subtle);
}

[data-theme="dark"] .icon-sun {
    display: inline;
}

[data-theme="dark"] .icon-moon {
    display: none;
}

[data-theme="light"] .icon-sun {
    display: none;
}

[data-theme="light"] .icon-moon {
    display: inline;
}

.btn-lang {
    background: var(--accent-subtle);
    border: 1px solid var(--accent);
    color: var(--accent);
    border-radius: var(--radius-sm);
    padding: 6px 12px;
    cursor: pointer;
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    transition: all var(--transition);
}

.btn-lang:hover {
    background: var(--accent);
    color: var(--bg-primary);
}

/* Mobile nav toggle */
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

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

@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }

    .nav-links {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--bg-nav);
        backdrop-filter: blur(20px);
        flex-direction: column;
        padding: 24px;
        gap: 12px;
        border-bottom: 1px solid var(--border);
        transform: translateY(-120%);
        opacity: 0;
        transition: transform var(--transition), opacity var(--transition);
    }

    .nav-links.active {
        transform: translateY(0);
        opacity: 1;
    }

    .nav-links li {
        width: 100%;
    }

    .nav-links a {
        display: block;
        width: 100%;
        text-align: center;
    }
}

/* ===== Hero ===== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: var(--hero-gradient);
    overflow: hidden;
}

.hero-bg-pattern {
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(var(--border) 1px, transparent 1px),
        linear-gradient(90deg, var(--border) 1px, transparent 1px);
    background-size: 60px 60px;
    opacity: 0.15;
}

.hero-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    padding-top: 100px;
    padding-bottom: 60px;
}

.hero-subtitle {
    color: var(--accent);
    font-weight: 600;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    margin-bottom: 16px;
}

.hero-title {
    font-family: var(--font-serif);
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 700;
    line-height: 1.15;
    margin-bottom: 24px;
    color: var(--text-primary);
}

.hero-desc {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 500px;
    margin-bottom: 36px;
    line-height: 1.8;
}

.hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

.chess-board-deco {
    position: relative;
    width: 300px;
    height: 300px;
}

.floating-piece {
    position: absolute;
    font-size: 4rem;
    opacity: 0.2;
    color: var(--accent);
    animation: float 6s ease-in-out infinite;
}

.piece-1 {
    top: 10%;
    left: 20%;
    animation-delay: 0s;
}

.piece-2 {
    top: 50%;
    left: 60%;
    animation-delay: 2s;
}

.piece-3 {
    bottom: 10%;
    left: 30%;
    animation-delay: 4s;
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0) rotate(0deg);
    }

    50% {
        transform: translateY(-20px) rotate(5deg);
    }
}

@media (max-width: 768px) {
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 40px;
    }

    .hero-desc {
        margin-left: auto;
        margin-right: auto;
    }

    .hero-actions {
        justify-content: center;
    }

    .hero-visual {
        display: none;
    }
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 28px;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    border: none;
    transition: all var(--transition);
    white-space: nowrap;
}

.btn-primary {
    background: var(--accent);
    color: #0a0a0f;
}

.btn-primary:hover {
    background: var(--accent-hover);
    color: #0a0a0f;
    transform: translateY(-1px);
    box-shadow: 0 4px 16px rgba(200, 162, 78, 0.3);
}

.btn-outline {
    background: transparent;
    border: 2px solid var(--border);
    color: var(--text-primary);
}

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

.btn-sm {
    padding: 8px 20px;
    font-size: 0.85rem;
}

.btn-full {
    width: 100%;
}

/* ===== Sections ===== */
.section {
    padding: 100px 0;
}

.section-alt {
    background: var(--bg-secondary);
}

.section-title {
    font-family: var(--font-serif);
    font-size: clamp(2rem, 3vw, 2.5rem);
    font-weight: 700;
    text-align: center;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    font-size: 1.05rem;
    max-width: 600px;
    margin: 0 auto 60px;
}

/* ===== About ===== */
.about-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 60px;
    align-items: start;
}

.about-text p {
    color: var(--text-secondary);
    margin-bottom: 20px;
    font-size: 1.05rem;
    line-height: 1.85;
}

.about-stats {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    text-align: center;
    transition: all var(--transition);
}

.stat-card:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow-card);
}

.stat-number {
    display: block;
    font-family: var(--font-serif);
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--accent);
    margin-bottom: 4px;
}

.stat-label {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    .about-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .about-stats {
        flex-direction: row;
        flex-wrap: wrap;
    }

    .stat-card {
        flex: 1;
        min-width: 140px;
    }
}

/* ===== Books ===== */
.category-title {
    font-family: var(--font-serif);
    font-size: 1.4rem;
    color: var(--accent);
    margin-bottom: 30px;
    margin-top: 50px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
}

.category-title:first-of-type {
    margin-top: 0;
}

.books-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
    gap: 28px;
    margin-bottom: 40px;
}

.book-card {
    display: grid;
    grid-template-columns: 140px 1fr;
    gap: 20px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    transition: all var(--transition);
}

.book-card:hover {
    background: var(--bg-card-hover);
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow-card);
}

.book-cover-wrap {
    position: relative;
}

.book-cover {
    width: 140px;
    height: 200px;
    object-fit: cover;
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-card);
}

.book-cover-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 10px;
    background: linear-gradient(135deg, var(--bg-secondary), var(--bg-card));
    border: 1px solid var(--border);
}

.placeholder-icon {
    font-size: 2.5rem;
    color: var(--accent);
}

.placeholder-title {
    font-size: 0.75rem;
    text-align: center;
    color: var(--text-secondary);
    padding: 0 8px;
    line-height: 1.4;
}

.book-year {
    position: absolute;
    top: 8px;
    right: 8px;
    background: var(--accent);
    color: #0a0a0f;
    font-size: 0.7rem;
    font-weight: 700;
    padding: 2px 8px;
    border-radius: 4px;
}

.book-info {
    display: flex;
    flex-direction: column;
}

.book-title {
    font-family: var(--font-serif);
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
    line-height: 1.3;
}

.book-desc {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 12px;
    flex-grow: 1;
}

.book-meta {
    font-size: 0.78rem;
    color: var(--text-muted);
    margin-bottom: 12px;
}

@media (max-width: 500px) {
    .books-grid {
        grid-template-columns: 1fr;
    }

    .book-card {
        grid-template-columns: 100px 1fr;
        gap: 14px;
        padding: 14px;
    }

    .book-cover {
        width: 100px;
        height: 145px;
    }
}

/* ===== Contact ===== */
.contact-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 60px;
    align-items: start;
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    background: var(--input-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: var(--font-sans);
    font-size: 0.95rem;
    transition: border var(--transition);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-subtle);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.form-status {
    font-size: 0.9rem;
    text-align: center;
    min-height: 1.5em;
}

.form-status.success {
    color: #4caf50;
}

.form-status.error {
    color: #f44336;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.contact-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    transition: all var(--transition);
}

.contact-card:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
}

.contact-icon {
    font-size: 1.5rem;
    margin-bottom: 8px;
    display: block;
}

.contact-card h4 {
    color: var(--text-primary);
    margin-bottom: 4px;
    font-size: 0.95rem;
}

.contact-card p,
.contact-card a {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .contact-info {
        flex-direction: row;
        flex-wrap: wrap;
    }

    .contact-card {
        flex: 1;
        min-width: 200px;
    }
}

/* ===== Footer ===== */
.footer {
    border-top: 1px solid var(--border);
    padding: 40px 0;
    background: var(--bg-secondary);
}

.footer-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.footer-logo {
    font-family: var(--font-serif);
    font-size: 1.1rem;
    color: var(--accent);
    margin-bottom: 4px;
}

.footer-left p,
.footer-right p {
    color: var(--text-muted);
    font-size: 0.85rem;
}

.footer-right {
    text-align: right;
}

@media (max-width: 600px) {
    .footer-container {
        flex-direction: column;
        text-align: center;
    }

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

/* ===== Smooth transitions ===== */
body,
.navbar,
.stat-card,
.book-card,
.contact-card,
.form-group input,
.form-group select,
.form-group textarea {
    transition: background-color var(--transition), color var(--transition), border-color var(--transition);
}