/**
 * MOBILE-FIRST CSS ARCHITECTURE
 * 
 * UX Decisions:
 * 1. Deep Space Theme: High contrast dark mode (#0f172a / slate-900 base). Easier on the eyes, saves battery on OLED phones, offers excellent contrast for colored cards in sunlight.
 * 2. Mobile-First Media Queries: Base styles are for mobile.
 * 3. Typography: Uses 'Inter' which is highly legible on small screens. Large, bold subject names (Info Hierarchy).
 * 4. Card Timeline: Completely eliminates the need for horizontal scrolling in the main view.
 * 5. Horizontal Tabs: Smooth swiping between days instead of a dropdown menu, requiring fewer taps.
 */

 :root {
    /* Color Palette - Slate Dark Mode */
    --bg-base: #0f172a;
    --bg-surface: #1e293b;
    --bg-surface-elevated: #334155;
    
    /* Text */
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #64748b;
    
    /* Brand & Accents */
    --brand-color: #3b82f6; /* Blue 500 */
    --brand-color-dim: rgba(59, 130, 246, 0.15);
    
    /* Subject Colors - Vivid but accessible on dark background */
    --color-math: #a78bfa; /* Violet 400 */
    --bg-math: rgba(167, 139, 250, 0.1);
    
    --color-lang: #60a5fa; /* Blue 400 */
    --bg-lang: rgba(96, 165, 250, 0.1);
    
    --color-science: #34d399; /* Emerald 400 */
    --bg-science: rgba(52, 211, 153, 0.1);
    
    --color-art: #f472b6; /* Pink 400 */
    --bg-art: rgba(244, 114, 182, 0.1);
    
    --color-sport: #fbbf24; /* Amber 400 */
    --bg-sport: rgba(251, 191, 36, 0.1);
    
    --color-eng: #38bdf8; /* Sky 400 */
    --bg-eng: rgba(56, 189, 248, 0.1);
    
    --color-empty: #475569; /* Slate 600 */
    --bg-empty: rgba(71, 85, 105, 0.05);

    /* Layout variables */
    --header-height: 120px;
    --safe-area-padding: env(safe-area-inset-bottom, 20px);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    -webkit-tap-highlight-color: transparent; /* Remove blue flash on mobile tap */
}

body {
    background-color: var(--bg-base);
    color: var(--text-primary);
    overflow-x: hidden; /* Strict no horizontal scroll */
    min-height: 100vh;
    font-size: 16px; /* Base size for mobile legibility */
}

.app-wrapper {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

/* -------------------------------------
 * FIXED HEADER 
 * ------------------------------------- */
.app-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background-color: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--bg-surface);
    padding-top: env(safe-area-inset-top, 10px); /* For iOS notch */
}

.header-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.25rem;
}

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

.brand .icon {
    color: var(--brand-color);
    font-size: 24px;
}

.brand h1 {
    font-size: 1.1rem;
    font-weight: 700;
    letter-spacing: -0.025em;
}

/* Styled Mobile Select */
.class-selector-wrapper {
    position: relative;
}

.class-selector-wrapper::after {
    content: "expand_more";
    font-family: 'Material Icons Round';
    position: absolute;
    right: 8px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--brand-color);
    pointer-events: none;
}

.class-select {
    appearance: none;
    background-color: var(--brand-color-dim);
    color: var(--brand-color);
    border: 1px solid rgba(59, 130, 246, 0.3);
    border-radius: 8px;
    padding: 0.5rem 2rem 0.5rem 1rem;
    font-size: 0.95rem;
    font-weight: 600;
    outline: none;
    cursor: pointer;
}

.class-select:focus {
    border-color: var(--brand-color);
}

/* -------------------------------------
 * DAY TABS 
 * ------------------------------------- */
.day-tabs-container {
    padding: 0 0.5rem 0.5rem;
}

.day-tabs {
    display: flex;
    list-style: none;
    gap: 0.5rem;
    overflow-x: auto;
    scrollbar-width: none; /* Auto-hide scrollbar Firefox */
    -ms-overflow-style: none; /* IE/Edge */
    padding: 0 0.75rem;
}

.day-tabs::-webkit-scrollbar {
    display: none; /* Chrome/Safari */
}

.tab {
    flex: 1 0 auto; /* Allow tabs to size naturally but not shrink below content */
    padding: 0.75rem 1rem;
    border-radius: 12px;
    color: var(--text-muted);
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all 0.2s ease;
    text-align: center;
    position: relative;
    user-select: none;
}

/* Active tab style */
.tab.active {
    color: var(--text-primary);
    background-color: var(--bg-surface);
}

.tab.active::after {
    content: '';
    position: absolute;
    bottom: -6px;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 3px;
    background-color: var(--brand-color);
    border-radius: 3px 3px 0 0;
}

/* Truncate tabs on very small screens (show only E, T, K, N, R) */
@media (max-width: 360px) {
    .tab span { display: none; }
    .tab { padding: 0.75rem; }
}

/* -------------------------------------
 * MAIN TIMELINE CONTENT
 * ------------------------------------- */
.timeline-container {
    flex-grow: 1;
    padding: 1.25rem 1.25rem;
    overflow-y: auto;
}

.day-summary {
    margin-bottom: 1.5rem;
}

.day-summary h2 {
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: -0.025em;
}

.lesson-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

/* -------------------------------------
 * LESSON CARDS
 * ------------------------------------- */
.lesson-card {
    display: flex;
    background-color: var(--bg-surface);
    border-radius: 16px;
    overflow: hidden;
    /* Box shadow for depth without clutter */
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    position: relative;
}

/* Thicker color accent bar on the left */
.lesson-card::before {
    content: '';
    width: 6px;
    flex-shrink: 0;
    background-color: var(--color-empty); /* default */
}

.time-column {
    padding: 1rem 0.5rem 1rem 1rem;
    display: flex;
    flex-direction: column;
    align-items: flex-end; /* Right align the times toward the content */
    justify-content: center;
    min-width: 85px;
    border-right: 1px solid rgba(255, 255, 255, 0.05);
}

.time-primary {
    font-size: 1.1rem;
    font-weight: 800;
    color: var(--text-primary);
    line-height: 1;
}

.time-secondary {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
    font-weight: 500;
}

.lesson-number {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--brand-color);
    margin-top: 0.5rem;
    font-weight: 700;
}

.info-column {
    padding: 1rem;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

/* Typography Hierarchy inside card */
.subject {
    font-size: 1.25rem;
    font-weight: 800;
    letter-spacing: -0.01em;
    margin-bottom: 0.5rem;
    line-height: 1.2;
}

.details {
    display: flex;
    flex-direction: column; /* Stacked on mobile */
    gap: 0.35rem;
}

.detail-item {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.detail-item .material-icons-round {
    font-size: 16px;
    color: var(--text-muted);
}

/* Empty State / Free period */
.lesson-card.is-empty {
    background-color: transparent;
    border: 2px dashed var(--bg-surface-elevated);
    box-shadow: none;
    align-items: center;
}
.lesson-card.is-empty::before { display: none; }
.lesson-card.is-empty .time-column { border-right: none; }

.free-period-text {
    color: var(--text-muted);
    font-size: 1rem;
    font-weight: 600;
    font-style: italic;
}

/* Subject Modifiers */
.sub-math::before { background-color: var(--color-math); }
.sub-math .subject { color: var(--color-math); }

.sub-lang::before { background-color: var(--color-lang); }
.sub-lang .subject { color: var(--color-lang); }

.sub-science::before { background-color: var(--color-science); }
.sub-science .subject { color: var(--color-science); }

.sub-art::before { background-color: var(--color-art); }
.sub-art .subject { color: var(--color-art); }

.sub-sport::before { background-color: var(--color-sport); }
.sub-sport .subject { color: var(--color-sport); }

.sub-eng::before { background-color: var(--color-eng); }
.sub-eng .subject { color: var(--color-eng); }

/* Current time/day highlighting */
.lesson-card.is-current {
    box-shadow: 0 0 0 2px var(--brand-color);
    background-color: rgba(59, 130, 246, 0.05); /* Slight blue tint */
}
.lesson-card.is-current .lesson-number {
    color: var(--text-primary);
    background-color: var(--brand-color);
    padding: 2px 6px;
    border-radius: 4px;
}

.bottom-spacer {
    height: var(--safe-area-padding);
}

/* -------------------------------------
 * DESKTOP ADAPTATION (Tablet and up)
 * ------------------------------------- */
@media (min-width: 768px) {
    body {
        /* Restrict max width and center it on large screens making it feel like an app */
        display: flex;
        justify-content: center;
        background-color: #020617; /* Even darker outer background */
    }
    
    .app-wrapper {
        width: 100%;
        max-width: 600px; /* Constraints width for comfortable reading */
        background-color: var(--bg-base);
        box-shadow: 0 0 40px rgba(0,0,0,0.5);
        position: relative;
    }
    
    .details {
        flex-direction: row; /* Horizontal details on tablet */
        gap: 1.5rem;
    }
}

/* -------------------------------------
 * WEEKLY VIEW & FAB
 * ------------------------------------- */

.floating-action-btn {
    position: fixed;
    bottom: 24px;
    right: 24px;
    background-color: var(--brand-color);
    color: white;
    border: none;
    border-radius: 28px;
    padding: 12px 20px;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1rem;
    font-weight: 600;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.4);
    cursor: pointer;
    z-index: 100;
    transition: transform 0.2s, background-color 0.2s;
    font-family: 'Inter', sans-serif;
}
.floating-action-btn:hover {
    background-color: #2563eb;
    transform: translateY(-2px);
}

.weekly-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 200;
    background-color: rgba(0, 0, 0, 0.6); /* backdrop */
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
}

.weekly-modal.show {
    opacity: 1;
    pointer-events: auto;
}

.weekly-modal-content {
    background-color: #ffffff;
    color: #1e293b; /* Dark text for light theme */
    width: 100%;
    max-width: 1200px;
    height: 100%;
    max-height: 90vh;
    border-radius: 16px;
    display: flex;
    flex-direction: column;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    overflow: hidden;
    font-family: 'Inter', sans-serif;
}

.weekly-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
    border-bottom: 1px solid #e2e8f0;
    background-color: #f8fafc;
}

.weekly-header h2 {
    font-size: 1.5rem;
    font-weight: 800;
    color: #0f172a;
    letter-spacing: -0.025em;
}

.close-btn {
    background: transparent;
    border: none;
    color: #64748b;
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.2s, color 0.2s;
}
.close-btn:hover {
    background-color: #e2e8f0;
    color: #0f172a;
}

.weekly-grid-container {
    padding: 1rem;
    overflow: auto;
    flex-grow: 1;
    background-color: #f1f5f9; /* sleek light background for the grid area */
}

/* Custom Scrollbar for the table */
.weekly-grid-container::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}
.weekly-grid-container::-webkit-scrollbar-track {
    background: #f1f5f9; 
}
.weekly-grid-container::-webkit-scrollbar-thumb {
    background: #cbd5e1; 
    border-radius: 4px;
}
.weekly-grid-container::-webkit-scrollbar-thumb:hover {
    background: #94a3b8; 
}

.weekly-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    min-width: 900px; /* Force minimum width to show all columns clearly */
    background-color: #ffffff;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
}

.weekly-table th, .weekly-table td {
    border-right: 1px solid #e2e8f0;
    border-bottom: 1px solid #e2e8f0;
    padding: 12px;
    vertical-align: top;
    text-align: left;
    width: 16.666%; /* 1 col for time, 5 config days = 6 cols */
}

.weekly-table th:last-child, .weekly-table td:last-child {
    border-right: none;
}

.weekly-table th {
    background-color: #f8fafc;
    font-weight: 700;
    color: #334155;
    text-align: center;
    position: sticky;
    top: 0;
    z-index: 10;
    border-bottom: 2px solid #cbd5e1;
    text-transform: uppercase;
    font-size: 0.85rem;
    letter-spacing: 0.05em;
}

.weekly-table .time-cell {
    font-weight: 600;
    color: #475569;
    background-color: #f8fafc;
    text-align: center;
    vertical-align: middle;
}

.weekly-lesson {
    background-color: #e0f2fe;
    border-left: 4px solid #3b82f6;
    border-radius: 6px;
    padding: 10px;
    margin-bottom: 8px;
    box-shadow: 0 1px 2px rgba(0,0,0,0.05);
    transition: transform 0.1s;
}

.weekly-lesson:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.weekly-lesson:last-child {
    margin-bottom: 0;
}

.wl-subject {
    font-weight: 800;
    color: #0c4a6e;
    font-size: 0.95rem;
    margin-bottom: 4px;
    line-height: 1.2;
}

.wl-detail {
    font-size: 0.8rem;
    color: #0369a1;
    display: flex;
    align-items: center;
    gap: 4px;
    margin-bottom: 2px;
    font-weight: 500;
}

.wl-detail .material-icons-round {
    font-size: 14px;
    opacity: 0.8;
}

.wl-empty {
    color: #cbd5e1;
    text-align: center;
    font-size: 0.85rem;
    padding-top: 10px;
    font-weight: 500;
}

/* Weekly View Subject Modifiers (Light Theme Adaptations) */
.wl-sub-math { background-color: rgba(139, 92, 246, 0.12); border-left-color: #8b5cf6; }
.wl-sub-math .wl-subject { color: #6d28d9; }
.wl-sub-math .wl-detail { color: #5b21b6; }

.wl-sub-lang { background-color: rgba(59, 130, 246, 0.12); border-left-color: #3b82f6; }
.wl-sub-lang .wl-subject { color: #1d4ed8; }
.wl-sub-lang .wl-detail { color: #1e40af; }

.wl-sub-science { background-color: rgba(16, 185, 129, 0.12); border-left-color: #10b981; }
.wl-sub-science .wl-subject { color: #047857; }
.wl-sub-science .wl-detail { color: #065f46; }

.wl-sub-art { background-color: rgba(236, 72, 153, 0.12); border-left-color: #ec4899; }
.wl-sub-art .wl-subject { color: #be185d; }
.wl-sub-art .wl-detail { color: #9d174d; }

.wl-sub-sport { background-color: rgba(245, 158, 11, 0.12); border-left-color: #f59e0b; }
.wl-sub-sport .wl-subject { color: #b45309; }
.wl-sub-sport .wl-detail { color: #92400e; }

.wl-sub-eng { background-color: rgba(14, 165, 233, 0.12); border-left-color: #0ea5e9; }
.wl-sub-eng .wl-subject { color: #0369a1; }
.wl-sub-eng .wl-detail { color: #075985; }