/* ===== CSS Variables ===== */
:root {
    --bg-color: #0f0f1a;
    --surface-color: #1a1a2e;
    --border-color: #2a2a4a;
    --text-color: #f1f5f9;
    --secondary-text: #94a3b8;
    --accent-color: #818cf8;
    --accent-hover: #6366f1;
    --success-color: #22c55e;
    --error-color: #ef4444;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: 'Inter', sans-serif;
    background: var(--bg-color);
    color: var(--text-color);
    min-height: 100vh;
    line-height: 1.6;
}

a {
    color: var(--accent-color);
    text-decoration: none;
    transition: color 0.2s;
}

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

/* ===== Navigation ===== */
.glass-nav {
    position: fixed;
    top: 20px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    align-items: center;
    gap: 2rem;
    padding: 1rem 2rem;
    background: rgba(26, 26, 46, 0.8);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    z-index: 1000;
    max-width: 90%;
}

.logo {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-color);
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: 1.5rem;
}

.nav-link {
    color: var(--secondary-text);
    font-weight: 500;
    transition: color 0.2s;
}

.nav-link:hover,
.nav-link.active {
    color: var(--accent-color);
}

.wallet-section {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.wallet-address {
    padding: 0.5rem 1rem;
    background: rgba(129, 140, 248, 0.1);
    border: 1px solid rgba(129, 140, 248, 0.3);
    border-radius: 25px;
    font-size: 0.85rem;
    color: var(--accent-color);
    cursor: pointer;
}

.btn-connect,
.btn-logout {
    padding: 0.5rem 1.25rem;
    border: none;
    border-radius: 25px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-connect {
    background: linear-gradient(135deg, var(--accent-color), var(--accent-hover));
    color: white;
}

.btn-connect:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

.btn-logout {
    background: transparent;
    border: 1px solid var(--error-color);
    color: var(--error-color);
}

.btn-logout:hover {
    background: rgba(239, 68, 68, 0.1);
}

/* ===== Container ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 120px 2rem 4rem;
}

/* ===== Hero ===== */
.hero {
    text-align: center;
    padding: 4rem 0;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--text-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--secondary-text);
    margin-bottom: 2rem;
}

.hero-badges {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.badge {
    padding: 0.5rem 1rem;
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    font-size: 0.9rem;
}

/* ===== Books Section ===== */
.books-section {
    margin-top: 3rem;
}

.books-section h2 {
    margin-bottom: 2rem;
    font-size: 1.5rem;
}

.books-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 2rem;
}

.book-card {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    overflow: hidden;
    transition: transform 0.2s, box-shadow 0.2s;
}

.book-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow);
}

.book-cover {
    height: 200px;
    background: linear-gradient(135deg, var(--accent-color), var(--accent-hover));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 4rem;
}

.book-info {
    padding: 1.5rem;
}

.book-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.book-author {
    color: var(--secondary-text);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.book-badges {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.book-badge {
    padding: 0.25rem 0.5rem;
    background: rgba(129, 140, 248, 0.1);
    border-radius: 4px;
    font-size: 0.75rem;
    color: var(--accent-color);
}

.btn-read {
    display: block;
    width: 100%;
    padding: 0.75rem;
    background: var(--accent-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

.btn-read:hover {
    background: var(--accent-hover);
}

.btn-read:disabled {
    background: var(--border-color);
    cursor: not-allowed;
}

/* ===== Info Section ===== */
.info-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 4rem;
}

.info-card {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2rem;
}

.info-card h3 {
    margin-bottom: 1rem;
}

.info-card ol {
    padding-left: 1.5rem;
    color: var(--secondary-text);
}

.info-card li {
    margin-bottom: 0.5rem;
}

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

.link {
    display: inline-block;
    margin-top: 1rem;
}

/* ===== Loading ===== */
.loading {
    text-align: center;
    padding: 3rem;
    color: var(--secondary-text);
    grid-column: 1 / -1;
}

/* ===== Footer ===== */
footer {
    text-align: center;
    padding: 3rem 2rem;
    color: var(--secondary-text);
    font-size: 0.9rem;
}

.footer-links {
    margin-top: 0.5rem;
}

.footer-links a {
    color: var(--secondary-text);
}

/* ===== Mobile Header ===== */
.mobile-header {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 60px;
    background: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
    z-index: 2000;
    align-items: center;
    justify-content: space-between;
    padding: 0 1rem;
}

.mobile-title {
    font-weight: 600;
    font-size: 1.1rem;
}

.icon-btn {
    background: transparent;
    border: none;
    color: var(--text-color);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.font-controls {
    display: flex;
    gap: 0.5rem;
}

.font-controls .icon-btn {
    font-size: 1rem;
    background: rgba(42, 42, 74, 0.5);
    border-radius: 4px;
    width: 32px;
    height: 32px;
}

/* ===== Viewer Page ===== */
.viewer-container {
    display: flex;
    height: 100vh;
    margin-top: 0;
    /* Reset for viewer */
    padding-top: 80px;
    /* Space for nav */
    overflow: hidden;
}

.sidebar {
    width: 300px;
    background: var(--surface-color);
    border-right: 1px solid var(--border-color);
    padding: 1.5rem;
    overflow-y: auto;
    transition: transform 0.3s ease;
    z-index: 1050;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .glass-nav {
        display: none;
        /* Hide main nav on viewer mobile */
    }

    .mobile-header {
        display: flex;
    }

    .viewer-container {
        padding-top: 60px;
        /* Space for mobile header */
        flex-direction: column;
    }

    .sidebar {
        position: fixed;
        top: 60px;
        left: 0;
        bottom: 0;
        width: 80%;
        /* 80% width sidebar */
        max-width: 300px;
        transform: translateX(-100%);
        /* Hidden by default */
        box-shadow: 2px 0 10px rgba(0, 0, 0, 0.5);
    }

    .sidebar.active {
        transform: translateX(0);
    }

    .reader-area {
        padding: 1rem;
        width: 100%;
        height: 100%;
    }

    .epub-container {
        border-radius: 0;
        /* Full width on mobile */
    }

    /* Overlay when sidebar is open */
    .sidebar-overlay {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background: rgba(0, 0, 0, 0.5);
        z-index: 1040;
        opacity: 0;
        pointer-events: none;
        transition: opacity 0.3s;
    }

    .sidebar-overlay.active {
        opacity: 1;
        pointer-events: auto;
    }
}