/* ============================================================
   STUDYVAULT - CSS
   A clean, modern design for a static document library.
   ============================================================ */

/* ---------- CSS Variables (easy to tweak) ---------- */
:root {
    --color-bg: #f9fafb;
    --color-surface: #ffffff;
    --color-text: #1f2937;
    --color-text-secondary: #6b7280;
    --color-primary: #2563eb;
    --color-primary-hover: #1d4ed8;
    --color-border: #e5e7eb;
    --color-badge-pdf: #dc2626;
    --color-badge-docx: #2563eb;
    --color-badge-ppt: #ea580c;
    --color-badge-txt: #6b7280;
    --color-badge-default: #4b5563;
    --shadow-card: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-card-hover: 0 10px 25px -5px rgba(0,0,0,0.08), 0 8px 10px -6px rgba(0,0,0,0.02);
    --radius: 12px;
    --transition: 0.2s ease;
}

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

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

/* ---------- Header ---------- */
.site-header {
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: 1.5rem 2rem;
    text-align: center;
}

.header-inner {
    max-width: 1100px;
    margin: 0 auto;
}

.logo-area {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.logo-icon {
    font-size: 2rem;
}

.site-title {
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: -0.5px;
    color: var(--color-text);
}

.site-description {
    color: var(--color-text-secondary);
    max-width: 700px;
    margin: 0.25rem auto 1.5rem;
    font-size: 0.95rem;
}

.site-description code {
    background: #f3f4f6;
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    font-size: 0.85em;
}

/* ---------- Search ---------- */
.search-wrapper {
    position: relative;
    max-width: 500px;
    margin: 0 auto 1rem;
    display: flex;
    align-items: center;
}

.search-icon {
    position: absolute;
    left: 1rem;
    font-size: 1rem;
    color: var(--color-text-secondary);
    pointer-events: none;
}

.search-input {
    width: 100%;
    padding: 0.7rem 2.5rem 0.7rem 2.5rem;
    border: 1px solid var(--color-border);
    border-radius: 2rem;
    font-size: 0.95rem;
    background-color: var(--color-bg);
    outline: none;
    transition: border-color var(--transition), box-shadow var(--transition);
}

.search-input:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.clear-search-btn {
    position: absolute;
    right: 0.75rem;
    background: none;
    border: none;
    font-size: 1.1rem;
    color: var(--color-text-secondary);
    cursor: pointer;
    padding: 0.2rem;
    display: none; /* shown via JS when input not empty */
    line-height: 1;
    transition: color var(--transition);
}

.clear-search-btn:hover {
    color: var(--color-text);
}

.clear-search-btn.visible {
    display: block;
}

.doc-count {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    margin: 0.25rem 0 0;
}

/* ---------- Category Filters ---------- */
.category-filters {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.5rem;
    margin: 1.5rem auto 1rem;
    max-width: 1100px;
    padding: 0 2rem;
}

.category-pill {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    padding: 0.4rem 1rem;
    border-radius: 2rem;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all var(--transition);
    color: var(--color-text);
    font-weight: 500;
}

.category-pill:hover {
    background: #f3f4f6;
    border-color: #d1d5db;
}

.category-pill.active {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

/* ---------- Document Grid ---------- */
.document-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
    max-width: 1100px;
    margin: 1rem auto 2rem;
    padding: 0 2rem;
    width: 100%;
}

/* ---------- Card ---------- */
.doc-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-card);
    transition: transform var(--transition), box-shadow var(--transition);
}

.doc-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-card-hover);
}

.card-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: 0.5rem;
}

.doc-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-right: 0.5rem;
    word-break: break-word;
}

.file-badge {
    display: inline-block;
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    padding: 0.2rem 0.6rem;
    border-radius: 1rem;
    color: white;
    background: var(--color-badge-default);
    white-space: nowrap;
    letter-spacing: 0.5px;
}

/* Badge colors by file type */
.file-badge.pdf { background: var(--color-badge-pdf); }
.file-badge.docx { background: var(--color-badge-docx); }
.file-badge.ppt, .file-badge.pptx { background: var(--color-badge-ppt); }
.file-badge.txt, .file-badge.md { background: var(--color-badge-txt); }
.file-badge.xlsx, .file-badge.csv { background: #059669; }
.file-badge.zip { background: #7c3aed; }

.doc-description {
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    margin: 0.5rem 0 1rem;
    flex: 1;
    line-height: 1.5;
}

.card-actions {
    display: flex;
    gap: 0.5rem;
    margin-top: auto;
    flex-wrap: wrap;
}

.btn {
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.3rem;
    padding: 0.45rem 1rem;
    font-size: 0.85rem;
    border-radius: 0.5rem;
    font-weight: 500;
    transition: background var(--transition), transform var(--transition);
    cursor: pointer;
    border: 1px solid transparent;
    background: var(--color-bg);
    color: var(--color-text);
}

.btn:hover {
    transform: translateY(-1px);
}

.btn-primary {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

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

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

.btn-outline:hover {
    background: var(--color-bg);
    border-color: #cbd5e1;
}

/* ---------- Loading & Empty States ---------- */
.loading-state {
    grid-column: 1 / -1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 3rem;
    color: var(--color-text-secondary);
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--color-border);
    border-top: 4px solid var(--color-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin-bottom: 1rem;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.empty-state {
    text-align: center;
    padding: 3rem 1rem;
    color: var(--color-text-secondary);
    max-width: 400px;
    margin: 0 auto;
}

.empty-icon {
    font-size: 3rem;
    display: block;
    margin-bottom: 1rem;
}

.btn-reset {
    margin-top: 1rem;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    padding: 0.5rem 1.5rem;
    border-radius: 2rem;
    font-size: 0.9rem;
    cursor: pointer;
    transition: background var(--transition);
}

.btn-reset:hover {
    background: #f3f4f6;
}

/* ---------- Footer ---------- */
.site-footer {
    margin-top: auto;
    text-align: center;
    padding: 1.5rem 2rem;
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    border-top: 1px solid var(--color-border);
    background: var(--color-surface);
}

.site-footer a {
    color: var(--color-primary);
    text-decoration: none;
}

/* ---------- Responsive ---------- */
@media (max-width: 640px) {
    .site-header {
        padding: 1.2rem 1rem;
    }

    .document-grid {
        grid-template-columns: 1fr;
        padding: 0 1rem;
    }

    .category-filters {
        padding: 0 1rem;
    }

    .card-actions {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }
}