:root {
    --bg-color: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --green-primary: #10b981;
    --green-light: #d1fae5;
    --green-dark: #047857;
    --blue-dark: #0f172a;
    --blue-medium: #1e293b;
    --blue-light: #e2e8f0;
    --card-bg: #ffffff;
    --card-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Open Sans', sans-serif;
    -webkit-tap-highlight-color: transparent;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    /* Mobile-like constraints */
    max-width: 100vw;
    overflow-x: hidden;
    padding-bottom: 80px; /* Space for bottom nav */
}

/* Header */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 24px 20px 16px;
    background-color: var(--bg-color);
    position: sticky;
    top: 0;
    z-index: 10;
}

.user-profile {
    display: flex;
    align-items: center;
    gap: 12px;
}

.avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--green-primary), var(--green-dark));
    display: flex;
    justify-content: center;
    align-items: center;
    color: white;
    font-size: 24px;
    box-shadow: 0 4px 10px rgba(16, 185, 129, 0.3);
}

.greeting p {
    font-size: 12px;
    color: var(--text-muted);
    margin-bottom: 2px;
}

.greeting h1 {
    font-size: 18px;
    font-weight: 700;
    color: var(--blue-dark);
}

.notification-btn {
    background: none;
    border: none;
    font-size: 24px;
    color: var(--blue-dark);
    position: relative;
    cursor: pointer;
}

.badge {
    position: absolute;
    top: -2px;
    right: -2px;
    background-color: #ef4444;
    color: white;
    font-size: 10px;
    font-weight: bold;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    border: 2px solid var(--bg-color);
}

/* Main Content */
.app-content {
    padding: 0 20px;
}

.section-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--blue-dark);
    margin: 24px 0 16px;
}

/* Metrics Grid */
.metrics-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.metric-card {
    background-color: var(--card-bg);
    border-radius: 20px;
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
    box-shadow: var(--card-shadow);
    border: 1px solid var(--blue-light);
    transition: transform 0.2s ease;
}

.metric-card:active {
    transform: scale(0.98);
}

.metric-icon {
    width: 40px;
    height: 40px;
    border-radius: 12px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 20px;
}

.metric-card.primary .metric-icon {
    background-color: var(--green-primary);
    color: white;
}

.metric-card.secondary .metric-icon {
    background-color: var(--blue-dark);
    color: white;
}

.metric-card.accent-blue .metric-icon {
    background-color: var(--blue-light);
    color: var(--blue-dark);
}

.metric-card.accent-green .metric-icon {
    background-color: var(--green-light);
    color: var(--green-dark);
}

.metric-info h3 {
    font-size: 12px;
    font-weight: 500;
    color: var(--text-muted);
}

.metric-info .value {
    font-size: 24px;
    font-weight: 700;
    color: var(--blue-dark);
    margin-top: 4px;
}

/* Course Cards */
.course-card {
    background-color: var(--card-bg);
    border-radius: 16px;
    padding: 16px;
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 16px;
    box-shadow: var(--card-shadow);
    border: 1px solid var(--blue-light);
}

.course-image {
    width: 60px;
    height: 60px;
    border-radius: 12px;
    background: linear-gradient(135deg, var(--green-primary), var(--green-dark));
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 32px;
    color: white;
    flex-shrink: 0;
}

.course-details {
    flex: 1;
}

.course-details h3 {
    font-size: 15px;
    font-weight: 600;
    color: var(--blue-dark);
    margin-bottom: 4px;
}

.course-details p {
    font-size: 12px;
    color: var(--text-muted);
    margin-bottom: 12px;
}

.progress-bar-container {
    height: 6px;
    background-color: var(--blue-light);
    border-radius: 3px;
    overflow: hidden;
    margin-bottom: 6px;
}

.progress-bar {
    height: 100%;
    background-color: var(--green-primary);
    border-radius: 3px;
}

.progress-text {
    font-size: 10px;
    color: var(--text-muted);
    font-weight: 500;
}

/* Bottom Navigation */
.bottom-nav {
    position: fixed;
    bottom: 15px;
    left: 15px;
    width: calc(100% - 30px);
    border-radius: 20px;
    height: 70px;
    background-color: var(--card-bg);
    display: flex;
    justify-content: space-around;
    align-items: center;
    box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.05);
    z-index: 100;
    padding-bottom: env(safe-area-inset-bottom);
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    text-decoration: none;
    color: var(--text-muted);
    transition: color 0.3s ease;
}

.nav-item ion-icon {
    font-size: 24px;
}

.nav-item span {
    font-size: 10px;
    font-weight: 500;
}

.nav-item.active {
    color: var(--green-primary);
}


/* Premium Course Card Styles */
.premium-course-card {
    background-color: #ffffff;
    border-radius: 20px;
    overflow: hidden;
    margin-bottom: 24px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.08);
    display: flex;
    flex-direction: column;
    border: none;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.premium-course-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 14px 30px rgba(0, 0, 0, 0.12);
}

.premium-thumbnail {
    width: 100%;
    height: 180px;
    background-color: #e2e8f0;
    position: relative;
}

.premium-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.premium-badge {
    position: absolute;
    top: 12px;
    left: 12px;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(4px);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    color: #334155;
    display: flex;
    align-items: center;
    gap: 4px;
}

.premium-details {
    padding: 16px;
    display: flex;
    flex-direction: column;
}

.premium-title {
    font-size: 18px;
    font-weight: 700;
    color: #1e293b;
    margin: 0 0 8px 0;
    line-height: 1.4;
}

.premium-desc {
    font-size: 13px;
    color: #64748b;
    margin: 0 0 16px 0;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.premium-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
    font-size: 12px;
    color: #94a3b8;
}

.premium-meta-item {
    display: flex;
    align-items: center;
    gap: 4px;
}

.premium-instructor {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 16px;
}

.instructor-avatar {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background-color: #cbd5e1;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 12px;
}

.instructor-name {
    font-size: 13px;
    font-weight: 500;
    color: #475569;
}

.premium-actions {
    display: flex;
    gap: 8px;
    align-items: center;
}

.premium-enroll-btn {
    flex: 1;
    background: #4f5be8;
    color: white;
    border: none;
    border-radius: 12px;
    padding: 12px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.premium-enroll-btn:hover {
    background: #3f4ac8;
    box-shadow: 0 4px 12px rgba(79, 91, 232, 0.3);
}

.premium-status {
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 700;
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

.premium-status.active {
    background: #ecfdf5;
    color: #047857;
    border: 1px solid #a7f3d0;
}

.premium-status.pending {
    background: #fffbeb;
    color: #b45309;
    border: 1px solid #fde68a;
}

.premium-status.rejected {
    background: #fef2f2;
    color: #b91c1c;
    border: 1px solid #fecaca;
}

/* Modal Overlay & Sheet */
.modal-overlay {
    position: fixed;
    top: 0; left: 0; width: 100vw; height: 100vh;
    background: rgba(15, 23, 42, 0.6);
    backdrop-filter: blur(4px);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 10000;
    padding: 20px;
}
.modal-overlay.active {
    display: flex;
}
.modal-sheet {
    background: #ffffff;
    width: 100%;
    max-width: 480px;
    border-radius: 16px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
    overflow: hidden;
    animation: sheetIn 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}
@keyframes sheetIn {
    from { transform: translateY(20px) scale(0.97); opacity: 0; }
    to { transform: translateY(0) scale(1); opacity: 1; }
}
.modal-sheet-header {
    padding: 16px 20px;
    border-bottom: 1px solid #e2e8f0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.modal-sheet-header h3 {
    margin: 0;
    font-size: 17px;
    color: #0f172a;
    font-weight: 700;
}
.close-sheet-btn {
    background: none;
    border: none;
    font-size: 22px;
    color: #64748b;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Star Rating Picker */
.star-rating-picker {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 28px;
    color: #cbd5e1;
    cursor: pointer;
}
.star-rating-picker ion-icon {
    transition: color 0.15s, transform 0.15s;
}
.star-rating-picker ion-icon:hover {
    transform: scale(1.15);
}
.star-rating-picker ion-icon.filled {
    color: #f59e0b;
}