@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@400;500;600;700;800&family=JetBrains+Mono:wght@500;700&display=swap');

:root {
    /* Palette: Pastel Light & Clean High Contrast */
    --bg-main: #f8fafc;
    --bg-card: #ffffff;
    --bg-subtle: #f1f5f9;
    
    --border-color: #e2e8f0;
    --border-dark: #cbd5e1;
    --border-active: #94a3b8;

    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;

    /* Pastel Category Accents (Sharp borders, soft fills) */
    --pastel-blue-bg: #e0f2fe;
    --pastel-blue-border: #38bdf8;
    --pastel-blue-text: #0369a1;

    --pastel-green-bg: #dcfce7;
    --pastel-green-border: #4ade80;
    --pastel-green-text: #15803d;

    --pastel-purple-bg: #f3e8ff;
    --pastel-purple-border: #c084fc;
    --pastel-purple-text: #6b21a8;

    --pastel-red-bg: #ffe4e6;
    --pastel-red-border: #fb7185;
    --pastel-red-text: #be123c;

    --pastel-amber-bg: #fef3c7;
    --pastel-amber-border: #fbbf24;
    --pastel-amber-text: #b45309;

    --pastel-gray-bg: #f1f5f9;
    --pastel-gray-border: #cbd5e1;
    --pastel-gray-text: #475569;

    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 12px -2px rgba(0, 0, 0, 0.05);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    border-radius: 0 !important; /* STRICT REQUIREMENT: NO ROUNDED CORNERS */
}

html, body {
    width: 100%;
    overflow-x: hidden; /* Prevents awkward horizontal scroll/zoom out */
}

body {
    font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: var(--bg-main);
    color: var(--text-primary);
    line-height: 1.4;
    font-size: 13px;
    -webkit-font-smoothing: antialiased;
}

.app-container {
    max-width: 1440px;
    margin: 0 auto;
    padding: 24px 32px 60px 32px;
    width: 100%;
}

/* Header Section */
.header-bar {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    padding: 20px 24px;
    margin-bottom: 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
    box-shadow: var(--shadow-sm);
    flex-wrap: wrap;
}

.title-area h1 {
    font-size: 20px;
    font-weight: 800;
    color: var(--text-primary);
    letter-spacing: -0.02em;
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.badge {
    background-color: var(--pastel-amber-bg);
    color: var(--pastel-amber-text);
    border: 1px solid var(--pastel-amber-border);
    font-size: 10px;
    font-weight: 800;
    padding: 3px 8px;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.subtitle {
    font-size: 12px;
    color: var(--text-secondary);
    margin-top: 4px;
}

.orig-tag {
    color: var(--pastel-red-text);
    font-weight: 600;
}

/* Header Controls (Desktop Layout) */
.header-controls {
    display: flex;
    align-items: center;
    gap: 16px;
}

.search-box {
    position: relative;
    width: 280px;
}

.search-input {
    width: 100%;
    background: var(--bg-subtle);
    border: 1px solid var(--border-color);
    padding: 8px 12px;
    font-size: 12px;
    color: var(--text-primary);
    outline: none;
}

.search-input:focus {
    background: var(--bg-card);
    border-color: var(--text-primary);
}

.stats-group {
    display: flex;
    gap: 10px;
    align-items: center;
}

.stat-box {
    background: var(--bg-subtle);
    border: 1px solid var(--border-color);
    padding: 6px 14px;
    text-align: center;
    min-width: 80px;
}

.stat-box.highlight {
    background: var(--pastel-amber-bg);
    border-color: var(--pastel-amber-border);
}

.stat-val {
    font-family: 'JetBrains Mono', monospace;
    font-size: 15px;
    font-weight: 700;
    color: var(--text-primary);
    display: block;
}

.stat-box.highlight .stat-val {
    color: var(--pastel-amber-text);
}

.stat-lbl {
    font-size: 9px;
    color: var(--text-muted);
    text-transform: uppercase;
    font-weight: 700;
    letter-spacing: 0.05em;
}

/* Main Layout Grid (Calendar + Content) */
.main-layout {
    display: flex;
    flex-direction: column;
    gap: 24px;
    width: 100%;
}

/* ==========================================
   Interactive Calendar Component (Top Screen)
   ========================================== */
.calendar-section {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    padding: 20px;
    box-shadow: var(--shadow-sm);
    width: 100%;
}

.calendar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border-color);
    gap: 12px;
    flex-wrap: wrap;
}

.calendar-title {
    font-size: 15px;
    font-weight: 700;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.calendar-title-sub {
    font-size: 12px;
    font-weight: 500;
    color: var(--text-muted);
}

.calendar-controls {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.btn-cal {
    background: var(--bg-subtle);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 6px 12px;
    font-size: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s ease;
}

.btn-cal:hover {
    background: #e2e8f0;
    border-color: var(--border-dark);
}

.btn-cal.active {
    background: var(--text-primary);
    color: #ffffff;
    border-color: var(--text-primary);
}

.calendar-month-selector {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

/* Filter Tags */
.filter-bar {
    display: flex;
    gap: 8px;
    margin-bottom: 16px;
    flex-wrap: wrap;
    align-items: center;
}

.filter-label {
    font-size: 11px;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    margin-right: 4px;
}

.filter-chip {
    background: var(--bg-subtle);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 6px 12px;
    font-size: 11px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s ease;
    white-space: nowrap;
}

.filter-chip:hover {
    border-color: var(--border-dark);
}

.filter-chip.active[data-filter="all"] {
    background: var(--text-primary);
    color: #fff;
    border-color: var(--text-primary);
}
.filter-chip.active[data-filter="class-type"] {
    background: var(--pastel-blue-bg);
    color: var(--pastel-blue-text);
    border-color: var(--pastel-blue-border);
}
.filter-chip.active[data-filter="task-type"] {
    background: var(--pastel-green-bg);
    color: var(--pastel-green-text);
    border-color: var(--pastel-green-border);
}
.filter-chip.active[data-filter="mentor-type"] {
    background: var(--pastel-purple-bg);
    color: var(--pastel-purple-text);
    border-color: var(--pastel-purple-border);
}
.filter-chip.active[data-filter="sim-type"] {
    background: var(--pastel-red-bg);
    color: var(--pastel-red-text);
    border-color: var(--pastel-red-border);
}
.filter-chip.active[data-filter="rev-type"] {
    background: var(--pastel-amber-bg);
    color: var(--pastel-amber-text);
    border-color: var(--pastel-amber-border);
}

/* Calendar Grid View */
.calendar-grid-wrapper {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    width: 100%;
}

.calendar-grid-header {
    display: grid;
    grid-template-columns: repeat(7, minmax(40px, 1fr));
    background: var(--bg-subtle);
    border: 1px solid var(--border-color);
    border-bottom: none;
    text-align: center;
    font-weight: 700;
    font-size: 11px;
    color: var(--text-secondary);
}

.cal-head-cell {
    padding: 8px 4px;
    border-right: 1px solid var(--border-color);
}
.cal-head-cell:last-child { border-right: none; }

.calendar-grid-body {
    display: grid;
    grid-template-columns: repeat(7, minmax(40px, 1fr));
    border: 1px solid var(--border-color);
    background: var(--bg-card);
}

.cal-day-cell {
    min-height: 80px;
    border-right: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    padding: 6px;
    background: var(--bg-card);
    transition: background 0.15s ease;
    position: relative;
}

.cal-day-cell:nth-child(7n) { border-right: none; }

.cal-day-cell.other-month {
    background: #fafafa;
    opacity: 0.4;
}

.cal-day-cell.has-events {
    cursor: pointer;
}

.cal-day-cell.has-events:hover {
    background: #f8fafc;
    border-color: var(--border-dark);
}

.cal-day-cell.selected {
    background: var(--pastel-blue-bg) !important;
    outline: 2px solid var(--pastel-blue-border);
    outline-offset: -2px;
}

.cal-date-number {
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px;
    font-weight: 700;
    color: var(--text-primary);
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 4px;
}

.cal-event-dots {
    display: flex;
    gap: 3px;
    flex-wrap: wrap;
}

.event-dot {
    width: 6px;
    height: 6px;
    background: var(--border-dark);
}
.event-dot.class-type { background: var(--pastel-blue-border); }
.event-dot.task-type { background: var(--pastel-green-border); }
.event-dot.mentor-type { background: var(--pastel-purple-border); }
.event-dot.sim-type { background: var(--pastel-red-border); }
.event-dot.rev-type { background: var(--pastel-amber-border); }

.cal-day-summary {
    font-size: 9.5px;
    color: var(--text-secondary);
    line-height: 1.2;
    overflow: hidden;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
}

/* ==========================================
   Weeks Accordion & List View (Clean Sharp)
   ========================================== */
.weeks-container {
    display: flex;
    flex-direction: column;
    gap: 16px;
    width: 100%;
}

.week-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    width: 100%;
}

.week-card.highlight-week {
    border-left: 4px solid var(--pastel-red-border);
}

.week-header {
    background: var(--bg-card);
    padding: 14px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    cursor: pointer;
    user-select: none;
    gap: 12px;
}

.week-header:hover {
    background: var(--bg-subtle);
}

.week-title-grp {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.week-title-grp h3 {
    font-size: 15px;
    font-weight: 700;
    color: var(--text-primary);
}

.week-range-text {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: 500;
}

.week-badge-pill {
    font-size: 10px;
    font-weight: 700;
    padding: 2px 8px;
    text-transform: uppercase;
    background: var(--pastel-blue-bg);
    color: var(--pastel-blue-text);
    border: 1px solid var(--pastel-blue-border);
}

.week-badge-pill.font-red {
    background: var(--pastel-red-bg);
    color: var(--pastel-red-text);
    border-color: var(--pastel-red-border);
}

.toggle-icon {
    font-size: 12px;
    color: var(--text-muted);
    transition: transform 0.2s ease;
}

.week-card.collapsed .days-grid {
    display: none;
}

.week-card.collapsed .toggle-icon {
    transform: rotate(-90deg);
}

/* Days Grid Layout (7 Columns Clean Sharp Grid) */
.days-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    background: var(--border-color);
    gap: 1px;
}

.day-cell {
    background: var(--bg-card);
    padding: 12px;
    min-height: 140px;
    display: flex;
    flex-direction: column;
    transition: background 0.15s ease;
}

.day-cell:hover {
    background: #fafafa;
}

.day-cell.empty-cell {
    background: var(--bg-subtle);
    opacity: 0.6;
}

.day-cell.free-study-cell {
    background: var(--pastel-amber-bg);
}

.day-header {
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 6px;
    margin-bottom: 8px;
}

.day-header-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2px;
}

.day-name {
    font-size: 11px;
    font-weight: 700;
    color: var(--text-secondary);
    text-transform: uppercase;
}

.day-date {
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px;
    font-weight: 700;
    color: var(--text-primary);
}

.day-time-badge {
    font-family: 'JetBrains Mono', monospace;
    font-size: 10px;
    font-weight: 600;
    background: var(--bg-subtle);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 1px 4px;
}

.orig-date {
    font-size: 10px;
    color: var(--pastel-red-text);
    font-weight: 600;
    display: block;
    margin-top: 2px;
}

.tasks-list {
    display: flex;
    flex-direction: column;
    gap: 6px;
    flex-grow: 1;
}

/* Individual Task Card Styling */
.task-item {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-left: 3px solid var(--border-dark);
    padding: 6px 8px;
    font-size: 11px;
    line-height: 1.35;
    color: var(--text-primary);
    transition: all 0.15s ease;
}

.task-item:hover {
    border-color: var(--border-dark);
    box-shadow: var(--shadow-sm);
}

.task-item.class-type {
    background: #f0f9ff;
    border-color: #bae6fd;
    border-left-color: var(--pastel-blue-border);
}
.task-item.task-type {
    background: #f0fdf4;
    border-color: #bbf7d0;
    border-left-color: var(--pastel-green-border);
}
.task-item.mentor-type {
    background: #faf5ff;
    border-color: #e9d5ff;
    border-left-color: var(--pastel-purple-border);
}
.task-item.sim-type {
    background: #fff1f2;
    border-color: #fecdd3;
    border-left-color: var(--pastel-red-border);
}
.task-item.rev-type {
    background: #fffbeb;
    border-color: #fde68a;
    border-left-color: var(--pastel-amber-border);
}

.task-code {
    font-family: 'JetBrains Mono', monospace;
    font-weight: 700;
    margin-right: 2px;
}

.task-time {
    font-family: 'JetBrains Mono', monospace;
    font-size: 10px;
    font-weight: 700;
    color: var(--pastel-amber-text);
    background: var(--pastel-amber-bg);
    padding: 0 4px;
    border: 1px solid var(--pastel-amber-border);
    float: right;
}

/* Exam Card Banner */
.exam-card {
    background: var(--pastel-red-bg);
    border: 1px solid var(--pastel-red-border);
    padding: 20px;
    text-align: center;
    color: var(--pastel-red-text);
    box-shadow: var(--shadow-sm);
    margin-top: 8px;
    width: 100%;
}

.exam-header-text {
    font-size: 11px;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.exam-card h4 {
    font-size: 18px;
    font-weight: 800;
    margin: 6px 0;
}

.exam-card p {
    font-size: 12px;
    font-weight: 500;
    opacity: 0.9;
}

/* ==========================================
   MOBILE & TABLET RESPONSIVE SYSTEM
   ========================================== */
@media (max-width: 1024px) {
    .app-container {
        padding: 16px 16px 40px 16px;
    }

    .days-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .header-bar {
        flex-direction: column;
        align-items: stretch;
        padding: 16px;
        gap: 16px;
    }

    .title-area h1 {
        font-size: 17px;
    }

    .header-controls {
        width: 100%;
        display: flex;
        flex-direction: column;
        gap: 12px;
    }

    .search-box {
        width: 100%;
    }

    .stats-group {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        gap: 8px;
        width: 100%;
    }

    .stat-box {
        min-width: unset;
        padding: 6px 4px;
    }

    .calendar-section {
        padding: 14px;
    }

    .calendar-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }

    .calendar-controls {
        width: 100%;
    }

    .calendar-month-selector {
        width: 100%;
        display: grid;
        grid-template-columns: repeat(4, 1fr);
        gap: 4px;
    }

    .btn-cal {
        text-align: center;
        padding: 8px 4px;
        font-size: 11px;
    }

    .filter-bar {
        overflow-x: auto;
        padding-bottom: 6px;
        -webkit-overflow-scrolling: touch;
        width: 100%;
        flex-wrap: nowrap;
    }

    .days-grid {
        grid-template-columns: repeat(1, 1fr);
    }

    .cal-day-cell {
        min-height: 65px;
        padding: 4px;
    }

    .cal-date-number {
        font-size: 10px;
    }

    .cal-day-summary {
        display: none; /* Hide dense text in mobile calendar grid for clean dots view */
    }
}

/* ==========================================
   Floating Back-To-Top Button (Clean Sharp)
   ========================================== */
.btn-back-to-top {
    position: fixed;
    bottom: 24px;
    right: 24px;
    background: var(--text-primary);
    color: #ffffff;
    border: 1px solid var(--text-primary);
    padding: 10px 14px;
    font-size: 11px;
    font-weight: 700;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 6px;
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.15);
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all 0.2s ease;
    z-index: 999;
}

.btn-back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.btn-back-to-top:hover {
    background: var(--pastel-blue-bg);
    color: var(--pastel-blue-text);
    border-color: var(--pastel-blue-border);
}

.arrow-up {
    font-size: 10px;
}