/* =========================================================
   BRIET Digital Lending — Stylesheet
   Clean, warm design inspired by library aesthetics
   ========================================================= */

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

:root {
    --color-primary: #C50025;
    --color-primary-light: #E03050;
    --color-accent: #FF002B;
    --color-bg: #FAFAF8;
    --color-surface: #FFFFFF;
    --color-text: #1A1A1A;
    --color-text-muted: #6B7280;
    --color-border: #E5E7EB;
    --color-warning: #92400E;
    --color-warning-bg: #FFFBEB;
    --radius: 8px;
    --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
    --max-width: 960px;
}

html { font-size: 16px; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* --- Header / Nav --- */
header {
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 100;
}

nav {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0.75rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-primary);
    letter-spacing: -0.02em;
}
.logo:hover { text-decoration: none; }
.logo span {
    font-weight: 400;
    color: var(--color-text-muted);
}

.nav-links { display: flex; align-items: center; gap: 1.25rem; }
.nav-links a { font-size: 0.9rem; color: var(--color-text-muted); }
.nav-links a:hover { color: var(--color-primary); text-decoration: none; }

/* --- Main content --- */
main {
    flex: 1;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 2rem 1.5rem;
    width: 100%;
}

/* --- Footer --- */
footer {
    text-align: center;
    padding: 1.5rem;
    color: var(--color-text-muted);
    font-size: 0.85rem;
    border-top: 1px solid var(--color-border);
    margin-top: auto;
}
footer a { color: var(--color-primary-light); }

/* --- Buttons --- */
.btn {
    display: inline-block;
    padding: 0.6rem 1.25rem;
    font-size: 0.95rem;
    font-weight: 500;
    border-radius: var(--radius);
    border: 2px solid transparent;
    cursor: pointer;
    text-align: center;
    transition: all 0.15s ease;
    text-decoration: none;
    font-family: inherit;
}
.btn:hover { text-decoration: none; }

.btn-primary {
    background: var(--color-primary);
    color: #fff;
    border-color: var(--color-primary);
}
.btn-primary:hover {
    background: var(--color-primary-light);
    border-color: var(--color-primary-light);
}

.btn-outline {
    background: transparent;
    color: var(--color-primary);
    border-color: var(--color-primary);
}
.btn-outline:hover {
    background: var(--color-primary);
    color: #fff;
}

.btn-full { width: 100%; }
.btn-small { padding: 0.35rem 0.75rem; font-size: 0.85rem; }

/* --- Hero section (landing page) --- */
.hero {
    text-align: center;
    padding: 3rem 0 2rem;
}
.hero h1 {
    font-size: 2.25rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 0.75rem;
    letter-spacing: -0.02em;
}
.hero .subtitle {
    font-size: 1.1rem;
    color: var(--color-text-muted);
    max-width: 560px;
    margin: 0 auto 1.5rem;
}
.hero .greeting {
    font-size: 1rem;
    margin-bottom: 1rem;
}
.hero-actions {
    display: flex;
    gap: 0.75rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* --- Feature cards (landing page) --- */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.25rem;
    margin: 2.5rem 0;
}
.feature-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
}
.feature-card h3 {
    font-size: 1.05rem;
    color: var(--color-primary);
    margin-bottom: 0.5rem;
}
.feature-card p {
    font-size: 0.9rem;
    color: var(--color-text-muted);
}

/* --- Info box --- */
.info-box {
    background: var(--color-warning-bg);
    border: 1px solid #FDE68A;
    border-radius: var(--radius);
    padding: 1.5rem;
    margin-top: 1rem;
}
.info-box h2 {
    font-size: 1.1rem;
    color: var(--color-warning);
    margin-bottom: 0.5rem;
}
.info-box p {
    font-size: 0.9rem;
    color: #78350F;
    margin-bottom: 0.5rem;
}
.info-box p:last-child { margin-bottom: 0; }

/* --- Auth page (OAuth simulation) --- */
.auth-page {
    display: flex;
    justify-content: center;
    padding: 2rem 0;
}
.auth-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
    padding: 2rem;
    width: 100%;
    max-width: 420px;
}
.auth-banner {
    background: var(--color-primary);
    color: #fff;
    text-align: center;
    padding: 0.5rem;
    border-radius: var(--radius);
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 1.25rem;
}
.auth-card h2 {
    font-size: 1.4rem;
    text-align: center;
    margin-bottom: 0.25rem;
}
.auth-description {
    text-align: center;
    color: var(--color-text-muted);
    font-size: 0.9rem;
    margin-bottom: 1.5rem;
}

.form-group {
    margin-bottom: 1rem;
}
.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 500;
    margin-bottom: 0.3rem;
    color: var(--color-text);
}
.form-group input {
    width: 100%;
    padding: 0.6rem 0.75rem;
    font-size: 0.95rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    font-family: inherit;
    transition: border-color 0.15s;
}
.form-group input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(197, 0, 37, 0.1);
}

.auth-note {
    text-align: center;
    font-size: 0.8rem;
    color: var(--color-text-muted);
    margin-top: 1.25rem;
    padding-top: 1rem;
    border-top: 1px solid var(--color-border);
}

/* --- Page sections (catalog, shelf) --- */
.page-section { padding: 1rem 0; }
.page-section h1 {
    font-size: 1.75rem;
    color: var(--color-primary);
    margin-bottom: 0.25rem;
}
.page-description {
    color: var(--color-text-muted);
    margin-bottom: 1.5rem;
}

/* --- Book grid --- */
.book-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.25rem;
}
.book-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow: hidden;
}
.book-cover {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    height: 180px;
    display: flex;
    align-items: flex-end;
    justify-content: flex-end;
    padding: 0.75rem;
    position: relative;
}
.book-cover--img {
    background: var(--color-border);
}
.book-cover img {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
}
.format-badge {
    background: rgba(255,255,255,0.9);
    color: var(--color-primary);
    padding: 0.2rem 0.6rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
}
.book-info {
    padding: 1.25rem;
}
.book-info h3 {
    font-size: 1.1rem;
    margin-bottom: 0.25rem;
}
.book-author {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    margin-bottom: 0.5rem;
}
.book-description {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    margin-bottom: 0.75rem;
}
.book-availability {
    font-size: 0.8rem;
    color: var(--color-accent);
    font-weight: 500;
    margin-bottom: 0.75rem;
}
.book-actions {
    display: flex;
    gap: 0.5rem;
}

.empty-state {
    text-align: center;
    padding: 3rem 0;
    color: var(--color-text-muted);
}
.empty-state .btn { margin-top: 1rem; }

/* --- Reader page --- */
.reader-page {
    display: flex;
    flex-direction: column;
    height: calc(100vh - 140px);
}
.reader-toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--color-border);
    margin-bottom: 0.75rem;
    flex-wrap: wrap;
    gap: 0.5rem;
}
.reader-info strong { margin-right: 0.5rem; }
.reader-author {
    color: var(--color-text-muted);
    font-size: 0.9rem;
}
.reader-actions {
    display: flex;
    gap: 0.5rem;
}
.reader-container {
    flex: 1;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    overflow: auto;
    min-height: 400px;
    background: #525659;
    text-align: center;
}
.reader-container canvas {
    display: block;
    margin: 0 auto;
    max-width: 100%;
}

/* PDF loading message */
.pdf-loading {
    padding: 3rem;
    color: #ccc;
    font-size: 1.1rem;
}

/* --- PDF viewer controls --- */
.pdf-controls {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1.5rem;
    padding: 0.4rem 0.75rem;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    margin-bottom: 0.5rem;
    flex-wrap: wrap;
}
.pdf-nav, .pdf-zoom {
    display: flex;
    align-items: center;
    gap: 0.4rem;
}
.pdf-btn {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 0.25rem 0.6rem;
    cursor: pointer;
    font-size: 1rem;
    line-height: 1;
    color: var(--color-text);
}
.pdf-btn:hover { background: var(--color-border); }
.pdf-btn-text { font-size: 0.85rem; padding: 0.3rem 0.6rem; }
.page-indicator {
    display: flex;
    align-items: center;
    gap: 0.3rem;
    font-size: 0.9rem;
    color: var(--color-text-muted);
}
.page-indicator input {
    width: 3.5rem;
    text-align: center;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 0.2rem;
    font-size: 0.9rem;
}
#zoom-level {
    font-size: 0.85rem;
    min-width: 2.5rem;
    text-align: center;
    color: var(--color-text-muted);
}

/* --- Book metadata line --- */
.book-meta {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    margin-bottom: 0.5rem;
}

/* --- Admin page --- */
.admin-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}
.admin-card h2 {
    font-size: 1.25rem;
    color: var(--color-primary);
    margin-bottom: 1rem;
}
.admin-form .form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}
.admin-form .form-group {
    margin-bottom: 1rem;
}
.admin-form textarea {
    width: 100%;
    padding: 0.6rem 0.75rem;
    font-size: 0.95rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    font-family: inherit;
    resize: vertical;
    transition: border-color 0.15s;
}
.admin-form textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(197, 0, 37, 0.1);
}
.cover-preview {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 0.5rem;
}
.cover-preview img {
    height: 80px;
    border-radius: var(--radius);
    border: 1px solid var(--color-border);
}
.cover-filename {
    font-size: 0.8rem;
    color: var(--color-text-muted);
}
.file-upload-label {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
}
.file-upload-input {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
}
.file-upload-name {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    margin-left: 0.5rem;
}

/* --- Responsive --- */
@media (max-width: 640px) {
    .hero h1 { font-size: 1.6rem; }
    nav { padding: 0.5rem 1rem; }
    main { padding: 1.25rem 1rem; }
    .book-grid { grid-template-columns: 1fr; }
    .reader-toolbar { flex-direction: column; align-items: flex-start; }
}