:root {
    --bg-color: #ffffff;
    --text-color: #333333;
    --primary-color: #003300; /* Dark Green */
    --accent-color: #FFD700; /* Gold */
    --border-color: #e0e0e0;
    --header-bg: #f8f9fa;
    --card-bg: #fdfdfd;
    --font-serif: 'Lora', serif;
    --font-sans: 'Roboto', sans-serif;
}

body {
    font-family: var(--font-sans);
    margin: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

/* --- Header & Footer --- */
.main-header {
    background-color: var(--header-bg);
    border-bottom: 2px solid var(--primary-color);
    padding: 1rem 0;
}

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

.logo h1 {
    font-family: var(--font-serif);
    color: var(--primary-color);
    margin: 0;
    font-size: 1.8rem;
}
.logo a {
    text-decoration: none;
}

nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    gap: 20px;
}

nav a {
    text-decoration: none;
    color: var(--primary-color);
    font-weight: bold;
    transition: color 0.3s;
}

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

.main-footer {
    background-color: var(--primary-color);
    color: white;
    text-align: center;
    padding: 1.5rem 0;
    margin-top: 40px;
}

/* --- Main Content --- */
main.container {
    padding-top: 40px;
    padding-bottom: 40px;
}

/* --- Buttons --- */
.btn {
    display: inline-block;
    background-color: var(--primary-color);
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    text-decoration: none;
    font-weight: bold;
    cursor: pointer;
    transition: background-color 0.3s;
}

.btn:hover {
    background-color: #004d00;
}

.btn-secondary {
    background-color: #6c757d;
}
.btn-secondary:hover {
    background-color: #5a6268;
}

.btn-danger {
    background-color: #dc3545;
}
.btn-danger:hover {
    background-color: #c82333;
}

.btn-sm {
    padding: 5px 10px;
    font-size: 0.9rem;
}

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

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

input[type="text"],
input[type="search"],
input[type="password"],
input[type="number"],
textarea,
select {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    box-sizing: border-box; /* Important */
}

textarea {
    resize: vertical;
}

/* --- Home Page: Filters --- */
.filters-section {
    background-color: var(--card-bg);
    padding: 20px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    margin-bottom: 40px;
}
.filters-form {
    display: flex;
    gap: 15px;
    align-items: center;
}
.filters-form .form-group {
    flex-grow: 1;
    margin-bottom: 0;
}

/* --- Home Page: Course List --- */
.course-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 25px;
}

.course-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

.course-card-header {
    padding: 15px 20px;
    border-bottom: 1px solid var(--border-color);
    background-color: #f8f9fa;
}

.course-card-header h3 {
    margin: 0;
    font-family: var(--font-serif);
}

.course-department {
    font-size: 0.9rem;
    color: #666;
}

.course-card-body {
    padding: 20px;
    flex-grow: 1;
}
.course-card-body p {
    margin: 0 0 10px 0;
}

.course-card-footer {
    padding: 15px 20px;
    background-color: #f8f9fa;
    text-align: right;
}

/* --- Course Detail Page --- */
.course-detail-container {
    background-color: var(--card-bg);
    padding: 30px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
}
.course-detail-header {
    border-bottom: 2px solid var(--accent-color);
    padding-bottom: 15px;
    margin-bottom: 20px;
}
.course-detail-header h1 {
    font-family: var(--font-serif);
    margin: 0;
}
.back-link {
    display: inline-block;
    margin-bottom: 20px;
    color: var(--primary-color);
    text-decoration: none;
}

.course-info-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    margin-top: 20px;
}
.info-item strong {
    display: block;
    color: var(--primary-color);
}

/* --- Login Page --- */
.login-container {
    max-width: 400px;
    margin: 40px auto;
    padding: 30px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
}
.login-form h2 {
    text-align: center;
    margin-top: 0;
}
.error-message {
    color: #dc3545;
    background-color: #f8d7da;
    border: 1px solid #f5c6cb;
    padding: 10px;
    border-radius: 5px;
    text-align: center;
}

/* --- Admin Page --- */
.admin-dashboard {
    display: grid;
    grid-template-columns: 1fr;
    gap: 40px;
}

.admin-form-section {
    background-color: var(--card-bg);
    padding: 25px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
}
.form-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.admin-list-section table {
    width: 100%;
    border-collapse: collapse;
}

.admin-list-section th, .admin-list-section td {
    padding: 12px;
    border: 1px solid var(--border-color);
    text-align: left;
}

.admin-list-section thead {
    background-color: var(--primary-color);
    color: white;
}

.admin-list-section .actions {
    display: flex;
    gap: 10px;
}