:root {
    --primary-color: #4a90e2;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --info-color: #17a2b8;
    --light-color: #f8f9fa;
    --dark-color: #343a40;
    --font-family-sans-serif: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
    --font-family-monospace: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
}

body {
    font-family: var(--font-family-sans-serif);
    background-color: #f4f7f6;
    color: #333;
    line-height: 1.6;
    margin: 0;
}

.container {
    width: 80%;
    margin: auto;
    overflow: hidden;
    padding: 0 20px;
}

h1, h2, h3, h4, h5, h6 {
    color: var(--dark-color);
}

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

.btn {
    display: inline-block;
    font-weight: 600;
    text-align: center;
    vertical-align: middle;
    user-select: none;
    background-color: var(--primary-color);
    border: 1px solid var(--primary-color);
    padding: 0.5rem 1rem;
    font-size: 1rem;
    line-height: 1.5;
    border-radius: 0.25rem;
    transition: all 0.15s ease-in-out;
    color: #fff;
    text-decoration: none;
    cursor: pointer;
}

.btn:hover {
    background-color: #357abd;
    border-color: #357abd;
}

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

.btn-danger:hover {
    background-color: #c82333;
    border-color: #bd2130;
}

.btn-sm {
    padding: 0.25rem 0.5rem;
    font-size: 0.875rem;
    line-height: 1.5;
    border-radius: 0.2rem;
}

.btn-primary {
    background: #0056d2;
    color: white;
}

.btn-primary:hover {
    background: #003d99;
}

.btn-outline {
    background: transparent;
    border: 1px solid #0056d2;
    color: #0056d2;
}

.btn-outline:hover {
    background: #f0f7ff;
}

.btn-white {
    background: white;
    color: #0056d2;
    padding: 14px 32px;
    font-size: 16px;
}

.btn-white:hover {
    background: #f0f0f0;
}

.card {
    background-color: #fff;
    padding: 2rem;
    border-radius: 0.5rem;
    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    margin-bottom: 2rem;
}

.form-container {
    background-color: #fff;
    padding: 2rem;
    border-radius: 0.5rem;
    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
}

.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

input[type="text"],
input[type="number"],
input[type="email"],
input[type="password"],
textarea,
select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ced4da;
    border-radius: 0.25rem;
    box-sizing: border-box;
    transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

input[type="text"]:focus,
input[type="number"]:focus,
input[type="email"]:focus,
input[type="password"]:focus,
textarea:focus,
select:focus {
    border-color: var(--primary-color);
    outline: 0;
    box-shadow: 0 0 0 0.2rem rgba(74, 144, 226, 0.25);
}

.table-container {
    background-color: #fff;
    padding: 2rem;
    border-radius: 0.5rem;
    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
}

table {
    width: 100%;
    border-collapse: collapse;
}

th, td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid #dee2e6;
}

thead th {
    vertical-align: bottom;
    border-bottom: 2px solid #dee2e6;
}

.module-item {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 0.5rem;
    margin-bottom: 1.5rem;
    border: 1px solid #e9ecef;
}

.module-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.module-header h4 {
    margin: 0;
}

.lesson-list-admin {
    list-style: none;
    padding-left: 0;
}

.lesson-list-admin li {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid #e9ecef;
}

.lesson-list-admin li:last-child {
    border-bottom: none;
}

/* Sidebar */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: 250px;
    height: 100vh;
    background: #2c3e50;
    color: white;
    padding-top: 20px;
}
.sidebar h2 {
    padding: 0 20px 20px;
    background: #2c3e50;
    margin:0;
    color: #fff;
}
.sidebar a {
    display: block;
    padding: 10px 20px;
    color: #bbb;
    text-decoration: none;
    font-size: 0.95rem;
}
.sidebar a:hover {
    background: #34495e;
    color: #fff;
}
.sidebar a.active {
    background: var(--primary-color);
    color: #fff;
}
.main {
    margin-left: 250px;
    padding: 30px;
}

/* Alerts */
.alert {
    padding: 15px;
    margin-bottom: 20px;
    border: 1px solid transparent;
    border-radius: 4px;
}
.alert-success {
    color: #155724;
    background-color: #d4edda;
    border-color: #c3e6cb;
}
.alert-danger {
    color: #721c24;
    background-color: #f8d7da;
    border-color: #f5c6cb;
}

/* Dashboard */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}
.stat-card {
    background: #fff;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.stat-card .number {
    font-size: 2rem;
    font-weight: 600;
}
.stat-card .label {
    font-size: 0.9rem;
    color: #666;
}
.pending-list {
    list-style: none;
    padding: 0;
}
.pending-list li {
    background: #fff;
    padding: 10px 15px;
    border-radius: 5px;
    margin-bottom: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

/* Landing Page */
header { background: #fff; border-bottom: 1px solid #e0e0e0; position: sticky; top: 0; z-index: 1000; box-shadow: 0 1px 4px rgba(0,0,0,0.05); }
.top-nav { background: #f8f9fa; padding: 8px 0; font-size: 13px; border-bottom: 1px solid #e0e0e0; }
.top-nav .container { display: flex; justify-content: flex-end; gap: 25px; }
.top-nav a { color: #545454; text-decoration: none; transition: color 0.2s; }
.top-nav a:hover { color: #0056d2; }
nav { padding: 16px 0; }
.flex { display: flex; align-items: center; justify-content: space-between; }
.logo { font-size: 32px; font-weight: 700; color: #0056d2; text-decoration: none; letter-spacing: -0.5px; }
.search-box { flex: 1; max-width: 500px; margin: 0 40px; position: relative; }
.search-box input { width: 100%; padding: 12px 45px 12px 20px; border: 1px solid #d1d1d1; border-radius: 4px; font-size: 15px; transition: all 0.2s; }
.search-box input:focus { outline: none; border-color: #0056d2; box-shadow: 0 0 0 2px rgba(0,86,210,0.1); }
.search-box button { position: absolute; right: 5px; top: 50%; transform: translateY(-50%); background: none; border: none; color: #666; font-size: 18px; cursor: pointer; padding: 8px 12px; }
.nav-links { display: flex; gap: 35px; align-items: center; }
.nav-links a { color: #1f1f1f; text-decoration: none; font-weight: 400; font-size: 15px; transition: color 0.2s; }
.nav-links a:hover { color: #0056d2; }
.hero { background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%); padding: 80px 0; }
.hero-content { max-width: 650px; }
.hero h1 { font-size: 56px; font-weight: 700; line-height: 1.2; margin-bottom: 20px; color: #1f1f1f; }
.hero p { font-size: 20px; color: #545454; margin-bottom: 32px; line-height: 1.5; }
.hero-img { max-width: 500px; }
.hero-img img { width: 100%; border-radius: 8px; }
.partners { background: white; padding: 50px 0; border-bottom: 1px solid #e0e0e0; }
.partners h3 { text-align: center; color: #545454; font-size: 14px; font-weight: 600; text-transform: uppercase; letter-spacing: 1px; margin-bottom: 30px; }
.partner-grid { display: flex; justify-content: center; align-items: center; gap: 50px; flex-wrap: wrap; }
.partner-logo { font-size: 24px; color: #aaa; font-weight: 600; }
section { padding: 80px 0; }
.section-header { margin-bottom: 40px; }
.section-header h2 { font-size: 40px; font-weight: 700; color: #1f1f1f; margin-bottom: 12px; }
.section-header p { font-size: 18px; color: #545454; }
.category-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 16px; }
.category-item { padding: 20px; background: #f8f9fa; border: 1px solid #e0e0e0; border-radius: 6px; text-align: center; text-decoration: none; color: inherit; transition: all 0.2s; }
.category-item:hover { background: #ffffff; border-color: #0056d2; box-shadow: 0 2px 8px rgba(0,86,210,0.1); }
.category-icon { font-size: 32px; color: #0056d2; margin-bottom: 12px; }
.category-name { font-size: 16px; font-weight: 600; color: #1f1f1f; }
.course-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 24px; }
.course-card { background: white; border: 1px solid #e0e0e0; border-radius: 6px; overflow: hidden; transition: all 0.2s; text-decoration: none; color: inherit; display: block; }
.course-card:hover { box-shadow: 0 4px 16px rgba(0,0,0,0.12); border-color: #ccc; }
.course-card img { width: 100%; height: 200px; object-fit: cover; }
.course-body { padding: 20px; }
.course-provider { font-size: 12px; color: #0056d2; font-weight: 600; text-transform: uppercase; margin-bottom: 8px; }
.course-title { font-size: 18px; font-weight: 700; color: #1f1f1f; margin-bottom: 8px; line-height: 1.3; }
.course-instructor { font-size: 14px; color: #666; margin-bottom: 12px; }
.course-meta { display: flex; justify-content: space-between; align-items: center; padding-top: 12px; border-top: 1px solid #f0f0f0; }
.course-rating { font-size: 14px; color: #666; }
.course-rating .stars { color: #f5a623; margin-right: 4px; }
.course-level { font-size: 13px; color: #666; background: #f0f0f0; padding: 4px 10px; border-radius: 3px; }
.course-price { font-size: 20px; font-weight: 700; color: #1f1f1f; margin-top: 8px; }
.promo-section { background: linear-gradient(135deg, #0056d2 0%, #003d99 100%); color: white; padding: 80px 0; text-align: center; }
.promo-section h2 { font-size: 42px; font-weight: 700; margin-bottom: 16px; }
.promo-section p { font-size: 20px; margin-bottom: 32px; opacity: 0.95; }
footer { background: #f8f9fa; padding: 60px 0 30px; border-top: 1px solid #e0e0e0; }
.footer-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 40px; margin-bottom: 40px; }
footer h4 { font-size: 16px; font-weight: 700; margin-bottom: 16px; color: #1f1f1f; }
footer ul { list-style: none; }
footer ul li { margin-bottom: 10px; }
footer a { color: #545454; text-decoration: none; font-size: 14px; transition: color 0.2s; }
footer a:hover { color: #0056d2; }
.footer-bottom { text-align: center; padding-top: 30px; border-top: 1px solid #e0e0e0; color: #666; font-size: 14px; }
.gap-16 { gap: 16px; }
.auth-wrapper { display: flex; justify-content: center; align-items: center; padding: 80px 0; }
.auth-container { max-width: 450px; width: 100%; padding: 40px; background: #fff; border-radius: 8px; box-shadow: 0 4px 16px rgba(0,0,0,0.1); }
.auth-container h2 { font-size: 28px; text-align: center; margin-bottom: 24px; }
.message { padding: 15px; margin-bottom: 20px; border-radius: 4px; border: 1px solid transparent; }
.message.error { background-color: #f8d7da; color: #721c24; border-color: #f5c6cb; }
.filters { background: white; padding: 20px; border-radius: 8px; margin-bottom: 30px; display: flex; gap: 15px; flex-wrap: wrap; }
.filter-group { flex: 1; min-width: 200px; }
.filter-group label { display: block; margin-bottom: 8px; font-weight: 600; font-size: 14px; }
.filter-group select, .filter-group input { width: 100%; padding: 10px; border: 1px solid #d1d1d1; border-radius: 4px; }
.empty-state { text-align: center; padding: 60px 20px; }
.empty-state i { font-size: 64px; color: #ccc; margin-bottom: 20px; }
@media (max-width: 768px) { .hero h1 { font-size: 36px; } .search-box { display: none; } .footer-grid { grid-template-columns: 1fr; } }