/* Style variables and design tokens */
:root {
    --bg-main: #0b0f19;
    --bg-card: #161d30;
    --bg-card-hover: #1e2840;
    --border-color: rgba(255, 255, 255, 0.08);
    --border-color-active: rgba(99, 102, 241, 0.4);
    
    --text-primary: #f3f4f6;
    --text-secondary: #9ca3af;
    --text-muted: #6b7280;
    
    --color-primary: #6366f1; /* Indigo */
    --color-primary-hover: #4f46e5;
    --color-accent: #8b5cf6; /* Violet */
    --color-accent-hover: #7c3aed;
    --color-success: #10b981; /* Emerald */
    --color-danger: #ef4444; /* Rose */
    
    --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --border-radius-lg: 12px;
    --border-radius-md: 8px;
    --border-radius-sm: 4px;
    
    --transition-fast: 0.15s ease;
    --transition-normal: 0.25s ease;
    
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
}

/* Base resets */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-main);
    color: var(--text-primary);
    font-family: var(--font-sans);
    line-height: 1.5;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
}

.youtube-player {
    width: 100%;
    min-height: 320px;
    border: 0;
    background: #000;
}

.provider-source-list {
    display: grid;
    gap: 0.45rem;
    margin-top: 0.75rem;
    list-style: none;
}

.provider-source-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    color: var(--text-secondary);
    font-size: 0.85rem;
}

/* Accessibility: Screen Reader only class */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Focus outline styles for accessibility */
button:focus-visible,
input:focus-visible,
video:focus-visible {
    outline: 3px solid var(--color-accent);
    outline-offset: 2px;
}

/* Layout Utilities */
.hidden {
    display: none !important;
}

/* Header styling */
.app-header {
    background-color: rgba(22, 29, 48, 0.8);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.25rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background: linear-gradient(135deg, #a78bfa, #6366f1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.logo-icon {
    width: 24px;
    height: 24px;
    stroke: url(#logo-grad); /* Fallback to solid color in code, using stroke color in SVG */
    stroke: #a78bfa;
}

.server-badge {
    background-color: rgba(99, 102, 241, 0.15);
    border: 1px solid rgba(99, 102, 241, 0.3);
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 500;
    color: #a5b4fc;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.status-dot {
    width: 8px;
    height: 8px;
    background-color: var(--color-success);
    border-radius: 50%;
    box-shadow: 0 0 8px var(--color-success);
    display: inline-block;
}

/* Main Container */
.app-main {
    flex: 1;
    max-width: 1200px;
    width: 100%;
    margin: 0 auto;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.login-card {
    max-width: 520px;
    width: 100%;
    align-self: center;
}

.login-form {
    display: grid;
    gap: 0.75rem;
    margin-top: 1rem;
}

.form-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.login-error {
    color: #fda4af;
    margin-top: 0.75rem;
}

.provider-card {
    display: grid;
    gap: 0.75rem;
}

.provider-heading {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 1rem;
}

.provider-heading .section-title {
    margin-bottom: 0.25rem;
}

.provider-status {
    flex: 0 0 auto;
    border: 1px solid rgba(245, 158, 11, 0.35);
    border-radius: 999px;
    color: #fbbf24;
    font-size: 0.75rem;
    padding: 0.25rem 0.65rem;
}

.provider-status-ready {
    border-color: rgba(16, 185, 129, 0.35);
    color: #6ee7b7;
}

/* Card Styling */
.card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    transition: border-color var(--transition-normal);
}

.card:hover {
    border-color: rgba(255, 255, 255, 0.12);
}

.section-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.25rem;
    letter-spacing: -0.025em;
    background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.section-subtitle {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

/* Common button styles */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    font-family: var(--font-sans);
    font-size: 0.875rem;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius-md);
    border: 1px solid transparent;
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.btn-primary:hover:not(:disabled) {
    background-color: var(--color-primary-hover);
}

.btn-secondary {
    background-color: rgba(255, 255, 255, 0.06);
    border-color: var(--border-color);
    color: var(--text-primary);
}

.btn-secondary:hover:not(:disabled) {
    background-color: rgba(255, 255, 255, 0.12);
}

.btn-accent {
    background: linear-gradient(135deg, var(--color-accent), var(--color-primary));
    color: white;
}

.btn-accent:hover:not(:disabled) {
    opacity: 0.9;
}

.btn-sm {
    padding: 0.25rem 0.75rem;
    font-size: 0.75rem;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Loading, Empty, and Error States */
.loading-state, .empty-state, .error-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 3rem 1.5rem;
    text-align: center;
    color: var(--text-secondary);
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid rgba(99, 102, 241, 0.1);
    border-top: 3px solid var(--color-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 1rem;
}

.spinner.small {
    width: 24px;
    height: 24px;
    border-width: 2px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.empty-icon {
    width: 48px;
    height: 48px;
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.subtext {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

.error-message {
    color: var(--color-danger);
    font-weight: 500;
    margin-bottom: 1rem;
}

/* Course List Styling */
.course-list {
    list-style: none;
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
}

@media (min-width: 640px) {
    .course-list {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .course-list {
        grid-template-columns: repeat(3, 1fr);
    }
}

.course-card {
    background-color: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-md);
    padding: 1.25rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    cursor: pointer;
    transition: all var(--transition-normal);
}

.course-card:hover {
    background-color: var(--bg-card-hover);
    border-color: var(--border-color-active);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.course-card-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.course-card-stats {
    font-size: 0.8rem;
    color: var(--text-secondary);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Progress bar container (course detail and card) */
.progress-container {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    width: 100%;
}

.progress-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.progress-bar-bg {
    background-color: rgba(255, 255, 255, 0.08);
    height: 6px;
    border-radius: 9999px;
    overflow: hidden;
    width: 100%;
}

.progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
    border-radius: 9999px;
    transition: width var(--transition-normal);
}

/* Course Header */
.course-header {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

@media (min-width: 640px) {
    .course-header {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
    }
}

.course-header-info {
    flex: 1;
}

.active-title {
    font-size: 1.35rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.btn-back {
    align-self: flex-start;
}

/* Dashboard Grid Layout */
.dashboard-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
}

@media (min-width: 900px) {
    .dashboard-grid {
        grid-template-columns: 1.75fr 1fr;
    }
}

/* Player section cards */
.player-card {
    padding: 0;
    overflow: hidden;
    margin-bottom: 1.5rem;
}

.video-container {
    position: relative;
    background-color: #000;
    aspect-ratio: 16/9;
    width: 100%;
}

#video-player {
    width: 100%;
    height: 100%;
    display: block;
}

.player-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    background-color: rgba(255, 255, 255, 0.02);
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    flex-wrap: wrap;
    gap: 1rem;
}

.playback-rates {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.control-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.rate-buttons {
    display: flex;
    gap: 0.25rem;
}

.btn-rate {
    padding: 0.25rem 0.5rem;
    font-size: 0.75rem;
    background-color: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    border-radius: var(--border-radius-sm);
    cursor: pointer;
}

.btn-rate:hover {
    background-color: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
}

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

.active-chapter-bar {
    padding: 1rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.active-chapter-bar h3 {
    font-size: 1rem;
    font-weight: 600;
}

.badge {
    font-size: 0.65rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding: 0.15rem 0.5rem;
    border-radius: 4px;
    background-color: var(--color-accent);
    color: white;
}

/* Bookmark section styling */
.bookmark-form {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.25rem;
}

.form-group {
    flex: 1;
}

.form-input {
    width: 100%;
    background-color: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.5rem 0.75rem;
    border-radius: var(--border-radius-md);
    font-family: var(--font-sans);
    font-size: 0.875rem;
    transition: all var(--transition-fast);
}

.form-input:focus {
    outline: none;
    border-color: var(--color-primary);
    background-color: rgba(255, 255, 255, 0.08);
}

.bookmark-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    max-height: 250px;
    overflow-y: auto;
}

.bookmark-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-md);
    padding: 0.6rem 0.75rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.bookmark-item:hover {
    background-color: rgba(255, 255, 255, 0.05);
    border-color: rgba(255, 255, 255, 0.15);
}

.bookmark-time {
    font-family: monospace;
    font-weight: 600;
    color: var(--color-primary);
    background-color: rgba(99, 102, 241, 0.1);
    padding: 0.15rem 0.4rem;
    border-radius: var(--border-radius-sm);
    font-size: 0.8rem;
}

.bookmark-note {
    font-size: 0.875rem;
    color: var(--text-secondary);
    flex: 1;
    margin-left: 0.75rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* Side panel: Chapters */
.side-panel {
    display: flex;
    flex-direction: column;
}

.side-panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.chapter-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    overflow-y: auto;
    max-height: 600px;
}

.chapter-item {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    background-color: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-md);
    padding: 0.75rem 1rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.chapter-item:hover {
    background-color: var(--bg-card-hover);
    border-color: rgba(255, 255, 255, 0.15);
}

.chapter-item.active {
    background-color: rgba(99, 102, 241, 0.1);
    border-color: var(--color-primary);
}

.chapter-item-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.chapter-title {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-primary);
    line-height: 1.3;
}

.chapter-item.active .chapter-title {
    color: #a5b4fc;
    font-weight: 600;
}

.chapter-duration {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.chapter-status {
    display: flex;
    align-items: center;
    gap: 0.35rem;
}

.completed-check {
    color: var(--color-success);
    display: flex;
    align-items: center;
}

/* Toast styling */
.toast-container {
    position: fixed;
    bottom: 1.5rem;
    right: 1.5rem;
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    pointer-events: none;
}

.toast {
    background-color: #1f2937;
    color: white;
    padding: 0.75rem 1.25rem;
    border-radius: var(--border-radius-md);
    border-left: 4px solid var(--color-accent);
    box-shadow: var(--shadow-lg);
    font-size: 0.875rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    pointer-events: auto;
    animation: slideIn 0.3s ease forwards;
    min-width: 250px;
    max-width: 350px;
}

.toast.toast-error {
    border-left-color: var(--color-danger);
}

.toast.toast-success {
    border-left-color: var(--color-success);
}

@keyframes slideIn {
    from {
        transform: translateY(1rem);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

/* Footer style */
.app-footer {
    background-color: rgba(11, 15, 25, 0.8);
    border-top: 1px solid var(--border-color);
    padding: 1.5rem;
    text-align: center;
    margin-top: auto;
    font-size: 0.75rem;
    color: var(--text-muted);
}