:root {
    --bg-body: #f8fafc;
    --bg-card: #ffffff;
    --text-main: #0f172a;
    --text-muted: #64748b;
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --primary-light: #eff6ff;
    --accent-green: #059669;
    --accent-green-hover: #047857;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-body);
    color: var(--text-main);
    line-height: 1.5;
    padding: 40px 20px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

/* Header Section */
header {
    text-align: center;
    margin-bottom: 32px;
}

header h1 {
    font-size: 2.25rem;
    font-weight: 700;
    color: var(--text-main);
    letter-spacing: -0.025em;
    margin-bottom: 6px;
}

header p {
    font-size: 1.1rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

/* Filter Alphabet Bar */
.filter-container {
    background: var(--bg-card);
    padding: 16px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    justify-content: center;
}

.filter-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 36px;
    height: 36px;
    padding: 0 10px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background: #ffffff;
    color: var(--text-main);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 600;
    transition: all 0.2s ease;
}

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

.filter-btn.active {
    background-color: var(--primary);
    color: #ffffff;
    border-color: var(--primary);
}

/* Meta Information */
.meta-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* Search Box */
.search-container {
    margin-bottom: 16px;
}

.search-input {
    width: 100%;
    padding: 10px 16px;
    font-size: 0.95rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    outline: none;
    background-color: #ffffff;
    transition: border-color 0.2s, box-shadow 0.2s;
}

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

/* Table Section */
.table-card {
    background: var(--bg-card);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
    overflow: hidden;
}

.table-responsive {
    width: 100%;
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
    font-size: 0.95rem;
}

th {
    background-color: #f1f5f9;
    color: var(--text-muted);
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.05em;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
}

td {
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-main);
}

tr:last-child td {
    border-bottom: none;
}

tr:hover td {
    background-color: #f8fafc;
}

/* Columns */
.col-no { 
    width: 80px; 
    text-align: center; 
    font-weight: 600; 
    color: var(--text-muted); 
}

.col-name { 
    font-weight: 600; 
    color: #1e293b; 
}

.col-manage { 
    width: 25%; 
}

.col-info { 
    width: 30%; 
}

.col-date { 
    width: 20%; 
    color: var(--text-muted); 
    font-size: 0.875rem; 
    display: table-cell; 
}

/* Links */
.btn-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

.btn-link:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

.btn-link.external {
    color: var(--accent-green);
}

.btn-link.external:hover {
    color: var(--accent-green-hover);
}

/* Empty State & Pagination */
.empty-state {
    text-align: center;
    padding: 40px;
    color: var(--text-muted);
}

.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 6px;
    margin-top: 24px;
}

.page-link {
    padding: 8px 14px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: #ffffff;
    color: var(--text-main);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
}

.page-link:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.page-link.active {
    background: var(--primary);
    color: #ffffff;
    border-color: var(--primary);
}

/* Responsive Breakpoints */
@media (max-width: 768px) {
    body { 
        padding: 20px 12px; 
    }
    
    header h1 { 
        font-size: 1.75rem; 
    }
    
    th, td { 
        padding: 12px 14px; 
    }

    /* Ẩn cột Ngày tạo trên thiết bị di động */
    .col-date { 
        display: none; 
    }
}