:root {
    --primary-color: #004085; /* Deep Blue - Professional */
    --secondary-color: #6c757d;
    --accent-color: #d32f2f; /* IELTS Red */
    --background-color: #f8f9fa;
    --text-color: #333;
    --sidebar-width: 260px;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    color: var(--primary-color);
}

a {
    text-decoration: none;
}

/* Navbar */
.navbar {
    background: #fff;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.navbar-brand {
    font-weight: 700;
    letter-spacing: 0.5px;
    font-size: 1.5rem;
}

.nav-link {
    font-weight: 500;
    color: #333; /* Dark color for white header */
}

.nav-link:hover {
    color: var(--primary-color);
}

/* Cards */
.card {
    border: none;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
    border-radius: 10px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    background: #fff;
    margin-bottom: 1.5rem;
}

.card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.1);
}

.card-header {
    background-color: #fff;
    border-bottom: 1px solid #f0f0f0;
    font-weight: 600;
    padding: 1rem 1.25rem;
    color: var(--primary-color);
}

.card-header.bg-primary {
    background-color: var(--primary-color) !important;
    color: #fff;
}

.card-header.bg-secondary {
    background-color: var(--secondary-color) !important;
}

/* Buttons */
.btn {
    border-radius: 6px;
    padding: 0.5rem 1.2rem;
    font-weight: 500;
    transition: all 0.2s;
}

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

.btn-primary:hover {
    background-color: #002b5e;
    border-color: #002b5e;
}

.btn-outline-primary {
    color: var(--primary-color);
    border-color: var(--primary-color);
}

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

/* Jumbotron / Hero */
.jumbotron {
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e7eb 100%);
    border-radius: 15px;
    box-shadow: inset 0 0 20px rgba(0,0,0,0.02);
}

/* Footer */
.footer {
    background-color: #212529 !important;
    color: #adb5bd;
    margin-top: auto;
}

.footer h5 {
    color: #fff;
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.footer a {
    color: #adb5bd;
}

.footer a:hover {
    color: #fff;
    text-decoration: underline;
}

/* Sidebar for Student Dashboard */
.list-group-item {
    border: none;
    border-left: 4px solid transparent;
    color: #555;
    font-weight: 500;
    padding: 12px 20px;
    transition: all 0.2s;
}

.list-group-item:hover {
    background-color: #f0f4ff;
    color: var(--primary-color);
}

.list-group-item.active {
    background-color: #eef4fc;
    color: var(--primary-color);
    border-color: transparent;
    border-left-color: var(--primary-color);
}

.list-group-item i {
    width: 25px;
    text-align: center;
}

/* Form Controls */
.form-control, .form-select {
    border-radius: 6px;
    border: 1px solid #ced4da;
    padding: 0.6rem 0.75rem;
}

.form-control:focus, .form-select:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(0, 64, 133, 0.25);
}

.form-floating > label {
    padding: 0.6rem 0.75rem;
}

/* Test Interface specific */
.test-header {
    background: #f8f9fa;
    border-bottom: 2px solid #ddd;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.test-body {
    background: #e9ecef;
}

.pane {
    background: #fff;
    box-shadow: 0 0 10px rgba(0,0,0,0.05);
}

.pane-left {
    border-right: 5px solid #e9ecef;
}

textarea {
    font-family: 'Courier New', Courier, monospace;
    line-height: 1.5;
    border: 1px solid #ced4da;
    border-radius: 4px;
}

textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 5px rgba(0, 64, 133, 0.2);
}

/* Alerts */
.alert {
    border: none;
    border-radius: 8px;
    box-shadow: 0 2px 6px rgba(0,0,0,0.05);
}