:root {
    --bg-gradient-start: #f8f9fa;
    --bg-gradient-end: #e9ecef;
    --sidebar-bg: #ffffff;
    --sidebar-hover: #f1f3f4;
    --sidebar-active: #0d6efd;
    --card-bg: #ffffff;
    --card-border: #dee2e6;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --accent-color: #0d6efd;
    --progress-bg: #e9ecef;
    --progress-fill: #0d6efd;
    --success-color: #198754;
    --info-color: #0dcaf0;
    --warning-color: #ffc107;
    --danger-color: #dc3545;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, var(--bg-gradient-start), var(--bg-gradient-end));
    color: var(--text-primary);
    min-height: 100vh;
    margin: 0;
}

/* --- Login Page --- */
#login-page { display: flex; justify-content: center; align-items: center; min-height: 100vh; }
.login-card { 
    background-color: var(--card-bg); 
    border: 1px solid var(--card-border); 
    border-radius: 15px; 
    padding: 40px; 
    box-shadow: 0 10px 30px rgba(0,0,0,0.1); 
    text-align: center; 
    width: 100%; 
    max-width: 400px; 
}
.login-card h2 { margin-bottom: 30px; font-weight: 600; color: var(--text-primary); }
.login-card .btn { margin: 10px; padding: 12px 25px; font-weight: 500; }

/* --- Sidebar --- */
.sidebar { 
    position: fixed; 
    top: 0; 
    left: 0; 
    height: 100vh; 
    width: 250px; 
    background-color: var(--sidebar-bg); 
    z-index: 1000; 
    transition: all 0.3s; 
    padding-top: 20px; 
    box-shadow: 2px 0 5px rgba(0,0,0,0.05); 
    border-right: 1px solid var(--card-border);
}
.sidebar .sidebar-brand { 
    display: flex; 
    align-items: center; 
    padding: 0 20px 20px 20px; 
    color: var(--text-primary); 
    font-size: 1.2rem; 
    font-weight: bold; 
    border-bottom: 1px solid var(--card-border); 
    text-decoration: none; 
}
.sidebar .sidebar-brand i { font-size: 2rem; margin-right: 15px; color: var(--accent-color); }
.sidebar .nav-link { 
    color: var(--text-secondary); 
    padding: 15px 25px; 
    display: flex; 
    align-items: center; 
    text-decoration: none; 
    transition: all 0.3s; 
    font-size: 1rem; 
    border-left: 3px solid transparent;
}
.sidebar .nav-link:hover { 
    background-color: var(--sidebar-hover); 
    color: var(--text-primary); 
    border-left: 3px solid var(--accent-color);
}
.sidebar .nav-link.active { 
    background-color: rgba(13, 110, 253, 0.1); 
    color: var(--accent-color); 
    border-left: 3px solid var(--accent-color);
}
.sidebar .nav-link i { margin-right: 15px; font-size: 1.2rem; }

/* --- Main Content --- */
.main-content { margin-left: 250px; padding: 20px; transition: all 0.3s; background-color: var(--bg-gradient-start); }

/* --- Top Bar --- */
.topbar { 
    background-color: var(--card-bg); 
    border: 1px solid var(--card-border); 
    border-radius: 10px; 
    padding: 20px 30px; 
    display: flex; 
    justify-content: space-between; 
    align-items: center; 
    margin-bottom: 25px; 
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}
.topbar .welcome-text h2 { margin: 0; font-size: 1.5rem; font-weight: 600; color: var(--text-primary); }
.topbar .user-details { font-size: 0.9rem; color: var(--text-secondary); }
.topbar .user-details span { color: var(--accent-color); font-weight: 500; }

/* --- Progress Bar --- */
.topbar .progress-container { display: flex; align-items: center; }
.circular-progress { position: relative; height: 60px; width: 60px; margin-right: 15px; }
.circular-progress svg { position: relative; width: 100%; height: 100%; transform: rotate(-90deg); }
.circular-progress svg circle { fill: none; stroke-width: 5; }
.circular-progress svg .bg-circle { stroke: var(--progress-bg); }
.circular-progress svg .progress-circle { stroke: var(--progress-fill); stroke-linecap: round; stroke-dasharray: 175.93; stroke-dashoffset: calc(175.93 - (175.93 * 44) / 100); transition: stroke-dashoffset 0.6s ease; }
.progress-text { display: flex; flex-direction: column; }
.progress-value { font-size: 1.5rem; font-weight: bold; color: var(--progress-fill); line-height: 1; }
.progress-label { font-size: 0.9rem; color: var(--text-secondary); }

/* --- Card & Stats --- */
.card { 
    background-color: var(--card-bg); 
    border: 1px solid var(--card-border); 
    border-radius: 10px; 
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05); 
    margin-bottom: 1.5rem; 
}
.card-header { 
    background-color: rgba(0,0,0,0.02); 
    border-bottom: 1px solid var(--card-border); 
    color: var(--text-primary); 
    font-weight: 600; 
    padding: 20px 25px; 
}
.card-body { padding: 1.5rem; }
.stat-card { border-left: 0.25rem solid; }
.stat-card.primary { border-left-color: #4e73df; }
.stat-card.success { border-left-color: var(--success-color); }
.stat-card.info { border-left-color: var(--info-color); }
.stat-card.warning { border-left-color: var(--warning-color); }
.stat-card .text-xs { font-size: 0.7rem; }
.stat-card .text-uppercase { text-transform: uppercase; }
.stat-card .font-weight-bold { font-weight: 700; }
.stat-card .text-gray-300 { color: #adb5bd; }
.stat-card .text-gray-800 { color: var(--text-primary); }
.stat-card .fa-2x { font-size: 2rem; }

/* --- Table --- */
.table {
    --bs-table-bg: transparent;
    --bs-table-striped-bg: rgba(0,0,0,0.02);
    --bs-table-hover-bg: rgba(0,0,0,0.04);
}
.table th, .table td { border-color: var(--card-border); vertical-align: middle; }
.table thead th { 
    border-bottom: 2px solid var(--accent-color); 
    white-space: nowrap; 
    background-color: rgba(0,0,0,0.02);
    color: var(--text-primary);
}
.table tbody tr:hover { background-color: var(--sidebar-hover); }

/* --- Form Controls --- */
.form-control, .form-select {
    background-color: #fff;
    color: var(--text-primary);
    border: 1px solid #ced4da;
}
.form-control:focus, .form-select:focus {
    background-color: #fff;
    color: var(--text-primary);
    border-color: #86b7fe;
    box-shadow: 0 0 0 0.25rem rgba(13, 110, 253, 0.25);
}
.form-control.bg-secondary, .form-select.bg-secondary {
    background-color: #f8f9fa !important;
    border-color: #dee2e6;
}

/* --- Accordion --- */
.accordion-item {
    background-color: #fff;
    border: 1px solid var(--card-border);
}
.accordion-button {
    background-color: rgba(0,0,0,0.02);
    color: var(--text-primary);
}
.accordion-button:not(.collapsed) {
    background-color: rgba(13, 110, 253, 0.1);
    color: var(--accent-color);
}
.accordion-body {
    background-color: #fff;
    color: var(--text-primary);
}

/* --- Modal --- */
.modal-content {
    background-color: #fff;
    color: var(--text-primary);
}
.modal-header, .modal-footer {
    border-color: var(--card-border);
}

/* --- Semester Toggle --- */
.semester-toggle { display: flex; justify-content: center; margin-bottom: 20px; }
.semester-toggle .btn { margin: 0 5px; }


/* --- Responsive --- */
@media (max-width: 768px) {
    .sidebar { margin-left: -250px; }
    .sidebar.show { margin-left: 0; }
    .main-content { margin-left: 0; }
    .topbar { flex-direction: column; align-items: flex-start; }
    .topbar .progress-container { margin-top: 15px; align-self: flex-end; }
}

/* --- Additional Styles for Nilai Page --- */
.badge {
    font-size: 0.85em;
    padding: 0.4em 0.8em;
    border-radius: 10px;
}

.table-hover tbody tr:hover {
    background-color: rgba(13, 110, 253, 0.05);
    transition: background-color 0.2s;
}

.btn-group-sm .btn {
    padding: 0.25rem 0.5rem;
    font-size: 0.875rem;
}

.modal-lg {
    max-width: 800px;
}

.form-control.bg-light {
    background-color: #f8f9fa !important;
    cursor: not-allowed;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .modal-lg {
        max-width: 95%;
    }
    
    .table-responsive {
        font-size: 0.9rem;
    }
    
    .btn-group-sm .btn {
        padding: 0.2rem 0.4rem;
    }
}