:root {
    --primary-color: #0056b3;
    --secondary-color: #f8f9fa;
    --accent-color: #007bff;
    --text-color: #333;
    --light-text: #666;
    --white: #ffffff;
    --bg-color: #f4f7f6;
    --card-bg: #ffffff;
    --nav-bg: #ffffff;
    --border-color: #ddd;
    --success: #28a745;
    --danger: #dc3545;
    --border-radius: 8px;
    --box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.dark-mode {
    --primary-color: #3d8bfd;
    --secondary-color: #2d3238;
    --accent-color: #3d8bfd;
    --text-color: #e1e1e1;
    --light-text: #aaa;
    --white: #1e1e1e; /* Used for some backgrounds */
    --bg-color: #121212;
    --card-bg: #1e1e1e;
    --nav-bg: #1e1e1e;
    --border-color: #444;
    --box-shadow: 0 2px 10px rgba(0,0,0,0.3);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navigation */
.navbar {
    background-color: var(--nav-bg);
    box-shadow: var(--box-shadow);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: background-color 0.3s;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 10px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    margin-left: 20px;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover, .nav-links a.active {
    color: var(--primary-color);
}

.btn {
    display: inline-block;
    padding: 10px 20px;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
}

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

.btn-primary:hover {
    background-color: #004494;
}

.btn-outline {
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    background: transparent;
}

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

/* Cards */
.card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 20px;
    box-shadow: var(--box-shadow);
    margin-bottom: 20px;
    transition: background-color 0.3s;
}

/* Dashboard Grid */
.dashboard-grid {
    display: grid;
    grid-template-columns: 250px 1fr;
    gap: 20px;
    margin-top: 30px;
}

.sidebar {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 20px;
    height: fit-content;
    box-shadow: var(--box-shadow);
}

.sidebar-menu {
    list-style: none;
}

.sidebar-menu li {
    margin-bottom: 10px;
}

.sidebar-menu a {
    text-decoration: none;
    color: var(--text-color);
    display: block;
    padding: 10px;
    border-radius: 4px;
    transition: background 0.3s;
}

.sidebar-menu a:hover, .sidebar-menu a.active {
    background-color: var(--secondary-color);
    color: var(--primary-color);
}

/* Exam List */
.exam-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.exam-card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 20px;
    border: 1px solid var(--border-color);
    transition: transform 0.2s, background-color 0.3s;
}

.exam-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.exam-meta {
    display: flex;
    justify-content: space-between;
    color: var(--light-text);
    font-size: 0.9rem;
    margin: 10px 0;
}

/* Forms */
.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
}

.form-control {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
    background-color: var(--card-bg);
    color: var(--text-color);
}

.form-control:focus {
    border-color: var(--primary-color);
    outline: none;
}

/* Footer */
.footer {
    background-color: #343a40;
    color: #fff;
    padding: 40px 0 20px;
    margin-top: 50px;
}