:root {
    --primary-color: #0a192f; /* Navy Blue */
    --secondary-color: #112240; /* Dark Indigo */
    --accent-color: #e63946; /* Red */
    --text-light: #ccd6f6;
    --text-dark: #333333;
    --bg-light: #ffffff;
    --bg-off-white: #f4f4f4;
}

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

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-weight: 700;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

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

.btn {
    display: inline-block;
    padding: 10px 20px;
    border-radius: 5px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
}

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

.btn-primary:hover {
    background-color: #c92a36;
}

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

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

.text-center { text-align: center; }
.mt-1 { margin-top: 1rem; }
.mt-2 { margin-top: 2rem; }
.mb-1 { margin-bottom: 1rem; }
.mb-2 { margin-bottom: 2rem; }

/* Header */
header {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

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

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: white;
}

.nav-links {
    display: flex;
    gap: 20px;
}

.nav-links a {
    color: var(--text-light);
    font-weight: 500;
}

.nav-links a:hover {
    color: var(--accent-color);
}

/* Hero Section */
.hero {
    background: linear-gradient(rgba(10, 25, 47, 0.9), rgba(10, 25, 47, 0.8)), url('../img/hero-bg.jpg'); /* Fallback or placeholder */
    background-size: cover;
    background-position: center;
    color: white;
    padding: 100px 0;
    text-align: center;
}

.hero h1 {
    color: white;
    font-size: 3rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    color: var(--text-light);
}

/* Features / About Preview */
.section {
    padding: 60px 0;
}

.bg-light {
    background-color: var(--bg-off-white);
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.card {
    background: white;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    border-top: 4px solid var(--accent-color);
}

/* Footer */
footer {
    background-color: var(--secondary-color);
    color: var(--text-light);
    padding: 40px 0;
    margin-top: auto;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 20px;
}

.footer-bottom {
    text-align: center;
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid rgba(255,255,255,0.1);
}

/* Forms */
.form-container {
    max-width: 400px;
    margin: 50px auto;
    padding: 30px;
    background: white;
    border-radius: 8px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

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

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

.form-group input, .form-group select, .form-group textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
}

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

/* Dashboard Sidebar (Simple implementation) */
.dashboard-container {
    display: flex;
    min-height: calc(100vh - 140px); /* Adjust based on header/footer height */
}

.sidebar {
    width: 250px;
    background-color: var(--primary-color);
    color: white;
    padding: 20px;
}

.sidebar a {
    display: block;
    padding: 10px;
    color: var(--text-light);
    margin-bottom: 5px;
    border-radius: 4px;
}

.sidebar a:hover, .sidebar a.active {
    background-color: var(--accent-color);
    color: white;
}

.main-content {
    flex: 1;
    padding: 30px;
    background-color: var(--bg-off-white);
}

/* Course Card */
.course-card {
    background: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

.course-card:hover {
    transform: translateY(-5px);
}

.course-img {
    height: 180px;
    background-color: #ddd;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #666;
}

.course-body {
    padding: 20px;
}

.course-title {
    font-size: 1.2rem;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.course-meta {
    font-size: 0.9rem;
    color: #666;
    margin-bottom: 15px;
}

/* Responsive Design */
.hamburger {
    display: none;
    cursor: pointer;
    font-size: 1.5rem;
    color: white;
}

@media (max-width: 768px) {
    .hamburger {
        display: block;
    }

    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: var(--primary-color);
        flex-direction: column;
        align-items: center;
        padding: 20px 0;
        box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links a {
        margin: 10px 0;
        width: 100%;
        text-align: center;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .grid-3 {
        grid-template-columns: 1fr;
    }

    .dashboard-container {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
    }
}