/* ======================================================= */
/* 1. KHAI BÁO BIẾN TOÀN CỤC & FONT */
/* ======================================================= */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

:root {
    /* Color Palette - Bảng màu đã được tinh chỉnh */
    --primary-color: #4A90E2;      /* Xanh dương hiện đại, tinh tế */
    --primary-light: rgba(74, 144, 226, 0.1);
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --info-color: #17a2b8;
    
    /* Background & Surface */
    --background-color: #f4f7fa;   /* Nền hơi xanh nhẹ, dịu mắt hơn */
    --card-background: #ffffff;
    --sidebar-background: #212529;
    
    /* Text */
    --text-color: #343a40;
    --text-muted: #6c757d;
    --link-color: var(--primary-color);
    --link-hover-color: #3a7bc8;

    /* Border & Shadow */
    --border-color: #dee2e6;
    --border-radius: 8px;          /* Bo góc nhẹ nhàng, nhất quán */
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 8px rgba(0,0,0,0.07);
    --shadow-lg: 0 10px 20px rgba(0,0,0,0.1);
}

body {
    font-family: 'Inter', sans-serif;
    margin: 0;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased; /* Giúp font chữ mượt hơn trên Webkit */
    -moz-osx-font-smoothing: grayscale;
}

/* ======================================================= */
/* 2. BỐ CỤC CHÍNH (Responsive) */
/* ======================================================= */
.container {
    display: flex;
    min-height: 100vh;
    width: 100%;
}

.main-content {
    flex: 1;
    padding: 24px;
    background-color: var(--background-color);
}

@media (max-width: 768px) {
    .container {
        flex-direction: column;
    }
    .main-content {
        padding: 16px;
    }
}

/* ======================================================= */
/* 3. SIDEBAR */
/* ======================================================= */
.sidebar {
    width: 250px;
    background-color: var(--sidebar-background);
    color: #e9ecef; /* Màu chữ sidebar sáng hơn */
    padding: 20px;
    box-shadow: var(--shadow-md);
    flex-shrink: 0;
    display: flex;
    flex-direction: column;
}

@media (max-width: 768px) {
    .sidebar {
        display: none;
    }
}

.sidebar .sidebar-header {
    font-size: 22px;
    margin-bottom: 30px;
    font-weight: 600;
    text-align: center;
    color: #fff;
}

.sidebar nav {
    flex-grow: 1; /* Đẩy mục đăng xuất xuống dưới */
}

.sidebar a {
    display: flex;
    align-items: center;
    padding: 12px 16px;
    margin-bottom: 8px; /* Thêm khoảng cách giữa các mục */
    text-decoration: none;
    color: #adb5bd; /* Màu chữ mục menu */
    border-radius: var(--border-radius);
    transition: background-color 0.2s, color 0.2s;
    font-weight: 500;
}

.sidebar a:hover {
    background-color: #343a40;
    color: #fff;
}

.sidebar a.active {
    background-color: var(--primary-color);
    color: #fff;
    box-shadow: var(--shadow-sm);
}

.sidebar a i {
    font-size: 18px;
    margin-right: 12px;
    width: 20px; /* Cố định chiều rộng icon */
    text-align: center;
}

.sidebar .logout-link {
    margin-top: auto; /* Tự động đẩy mục này xuống cuối */
}

/* ======================================================= */
/* 4. CÁC THÀNH PHẦN CHUNG */
/* ======================================================= */
.page-title {
    background-color: var(--card-background);
    color: var(--text-color);
    padding: 20px 24px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
    font-size: 22px;
    font-weight: 600; /* Chữ tiêu đề đậm hơn */
    text-align: left;
    border-left: 4px solid var(--primary-color);
}

.card, .main-panel { /* Gom nhóm .card và .main-panel */
    background-color: var(--card-background);
    padding: 24px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color); /* Thêm viền nhẹ */
}

/* --- Form Elements --- */
.form-group input, 
.form-group select,
input[type="text"], 
input[type="email"], 
input[type="password"], 
input[type="number"], 
select,
.form-control {
    width: 100%;
    box-sizing: border-box;
    background-color: #f8f9fa;
    border: 1px solid #dee2e6;
    border-radius: var(--border-radius);
    padding: 12px 15px;
    font-size: 1rem;
    color: var(--text-color);
    box-shadow: inset 0 1px 2px rgba(0,0,0,0.075);
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.form-group input:focus, 
.form-group select:focus,
input[type="text"]:focus, 
input[type="email"]:focus, 
input[type="password"]:focus, 
input[type="number"]:focus, 
select:focus,
.form-control:focus {
    border-color: var(--primary-color);
    background-color: #fff;
    outline: none;
    box-shadow: 0 0 0 3px var(--primary-light);
}

/* --- Buttons --- */
.btn, .btn-primary, .btn-secondary, .btn-action, .btn-danger {
    border: none;
    border-radius: var(--border-radius);
    padding: 12px 24px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: all 0.2s ease-out;
}

.btn-primary, .btn-action {
    background: linear-gradient(180deg, var(--primary-color) 0%, #3a7bc8 100%);
    color: #fff;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1), inset 0 1px 0 rgba(255,255,255,0.1);
}

.btn-primary:hover, .btn-action:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.15), inset 0 1px 0 rgba(255,255,255,0.1);
    filter: brightness(1.05);
}

.btn-secondary {
    background-color: var(--card-background);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.btn-secondary:hover {
    background-color: #f8f9fa;
    border-color: #adb5bd;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.btn-danger {
    background-color: var(--danger-color);
    color: #fff;
}

/* --- Tables --- */
.table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 24px;
    background-color: var(--card-background);
    box-shadow: var(--shadow-sm);
    border-radius: var(--border-radius);
    overflow: hidden;
    border: 1px solid var(--border-color);
}
.table th, .table td {
    border-bottom: 1px solid var(--border-color); /* Chỉ giữ viền dưới */
    padding: 14px 16px; /* Tăng padding */
    text-align: left;
    font-size: 14px;
    vertical-align: middle;
}
.table th {
    background-color: #f8f9fa;
    font-weight: 600;
    color: var(--text-color);
}
.table tbody tr:hover {
    background-color: var(--primary-light); /* Highlight hàng khi hover */
}
.table td a {
    color: var(--link-color);
    text-decoration: none;
    font-weight: 500;
}
.table td a:hover {
    text-decoration: underline;
}

/* --- Alerts --- */
.alert {
    padding: 16px;
    border-left: 4px solid;
    border-radius: var(--border-radius);
    margin-bottom: 24px;
    font-weight: 500;
}
.alert.success {
    background-color: #eaf7ed;
    color: #2a6f3d;
    border-color: var(--success-color);
}
.alert.error {
    background-color: #fbe9eb;
    color: #8c2f39;
    border-color: var(--danger-color);
}

/* --- Modal --- */
.modal {
    /* Giữ nguyên như cũ */
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex; justify-content: center; align-items: center;
    z-index: 1050; opacity: 0; visibility: hidden;
    transition: all 0.3s ease;
}
.modal.show {
    opacity: 1; visibility: visible;
}
.modal-content {
    background-color: var(--card-background); padding: 24px;
    border-radius: var(--border-radius); width: 90%; max-width: 600px;
    box-shadow: var(--shadow-lg); position: relative;
    transform: translateY(-50px);
    transition: transform 0.3s ease;
}
.modal.show .modal-content { transform: translateY(0); }
.close-btn {
    position: absolute; top: 12px; right: 18px; font-size: 24px;
    font-weight: bold; color: var(--text-muted); cursor: pointer;
    transition: color 0.2s ease;
}
.close-btn:hover { color: var(--text-color); }