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

  :root {
    --bg: #080b12;
    --bg2: #0e1420;
    --bg3: #141c2e;
    --surface2: #141c2e;
    --surface3: #1a2440;
    --border: rgba(255,255,255,0.07);
    --cyan: #00e5c8;
    --amber: #f0a500;
    --red: #ff4d6d;
    --green: #39d98a;
    --text: #e8eaf0;
    --muted: #5a6480;
    --font-mono: 'Space Mono', monospace;
    --font: 'Outfit', sans-serif;
  }

  :root.light {
    --bg: #f0f2f7;
    --bg2: #ffffff;
    --bg3: #e8ecf4;
    --surface2: #ebeef5;
    --surface3: #dde2ee;
    --border: rgba(0,0,0,0.09);
    --cyan: #0099aa;
    --amber: #b87800;
    --red: #d6294a;
    --green: #1e9e5a;
    --text: #1a1e2e;
    --muted: #8892aa;
  }

  html, body {
    background: var(--bg);
    color: var(--text);
    font-family: var(--font);
    height: 100%;
    overflow: hidden;
  }

  /* HEADER */
  header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 24px;
    height: 58px;
    background: var(--bg2);
    border-bottom: 1px solid var(--border);
    position: relative;
    z-index: 10;
  }
  .logo {
    display: flex;
    align-items: center;
    gap: 10px;
  }
  .logo-icon {
    width: 32px; height: 32px;
    background: linear-gradient(135deg, var(--cyan), #0066ff);
    border-radius: 8px;
    display: flex; align-items: center; justify-content: center;
    font-size: 14px;
  }
  .logo-text {
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 0.5px;
  }
  .logo-sub {
    font-family: var(--font-mono);
    font-size: 10px;
    color: var(--muted);
    margin-top: 1px;
  }
  .header-center {
    display: flex;
    align-items: center;
    gap: 12px;
  }
  .file-zone {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 6px 14px;
    border: 1px dashed var(--border);
    border-radius: 6px;
    cursor: pointer;
    transition: border-color 0.2s, background 0.2s;
    font-size: 12px;
    color: var(--muted);
  }
  .file-zone:hover {
    border-color: var(--cyan);
    background: rgba(0, 229, 200, 0.05);
    color: var(--cyan);
  }
  .file-zone.loaded {
    border-color: rgba(57, 217, 138, 0.4);
    color: var(--green);
  }
  .file-zone input { display: none; }
  .file-dot {
    width: 6px; height: 6px;
    border-radius: 50%;
    background: var(--green);
    box-shadow: 0 0 6px var(--green);
    animation: pulse 2s infinite;
  }
  @keyframes pulse { 0%,100%{opacity:1} 50%{opacity:0.4} }

  .theme-toggle {
    width: 32px; height: 32px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: var(--bg3);
    color: var(--text);
    font-size: 15px;
    cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    transition: background 0.15s, border-color 0.15s;
    flex-shrink: 0;
  }
  .theme-toggle:hover { background: var(--surface3); border-color: var(--cyan); }

  .header-right {
    display: flex;
    align-items: center;
    gap: 16px;
  }
  .ects-badge {
    font-family: var(--font-mono);
    font-size: 11px;
    padding: 5px 12px;
    background: rgba(240, 165, 0, 0.12);
    border: 1px solid rgba(240, 165, 0, 0.35);
    border-radius: 20px;
    color: var(--amber);
  }
  .ects-num {
    font-size: 16px;
    font-weight: 700;
    margin-right: 2px;
  }
  .conflict-badge {
    display: none;
    font-family: var(--font-mono);
    font-size: 10px;
    padding: 5px 10px;
    background: rgba(255, 77, 109, 0.1);
    border: 1px solid rgba(255, 77, 109, 0.3);
    border-radius: 20px;
    color: var(--red);
    gap: 5px;
    align-items: center;
  }
  .conflict-badge.visible { display: flex; }

  /* MAIN LAYOUT */
  main {
    display: grid;
    grid-template-columns: 340px 1fr;
    height: calc(100vh - 58px);
    overflow: hidden;
  }

  /* LEFT PANEL */
  .left-panel {
    background: var(--bg2);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    overflow: hidden;
  }
  .panel-header {
    padding: 14px 18px 10px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
  }
  .panel-title {
    font-family: var(--font-mono);
    font-size: 10px;
    letter-spacing: 1.5px;
    color: var(--muted);
    text-transform: uppercase;
  }
  .panel-count {
    font-family: var(--font-mono);
    font-size: 10px;
    color: var(--cyan);
  }
  .search-wrap {
    padding: 10px 14px;
    border-bottom: 1px solid var(--border);
  }
  .search-input {
    width: 100%;
    background: var(--bg3);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 7px 10px 7px 30px;
    font-family: var(--font);
    font-size: 12px;
    color: var(--text);
    outline: none;
    transition: border-color 0.2s;
    position: relative;
  }
  .search-wrap { position: relative; }
  .search-icon {
    position: absolute;
    left: 24px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--muted);
    font-size: 12px;
    pointer-events: none;
  }
  .search-input:focus { border-color: var(--cyan); }
  .search-input::placeholder { color: var(--muted); }

  .courses-list {
    flex: 1;
    overflow-y: auto;
    padding: 8px 10px;
    display: flex;
    flex-direction: column;
    gap: 5px;
  }
  .courses-list::-webkit-scrollbar { width: 4px; }
  .courses-list::-webkit-scrollbar-track { background: transparent; }
  .courses-list::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }

  .course-card {
    background: var(--bg3);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 10px 12px;
    transition: border-color 0.2s, transform 0.1s;
    cursor: default;
    animation: slideIn 0.3s ease both;
  }
  @keyframes slideIn {
    from { opacity: 0; transform: translateY(-6px); }
    to { opacity: 1; transform: translateY(0); }
  }
  .course-card:hover { border-color: rgba(255,255,255,0.14); }
  .course-card.active { border-color: rgba(0,229,200,0.25); }
  .course-card.highlighted {
    border-color: var(--cyan) !important;
    box-shadow: 0 0 0 2px rgba(0,229,200,0.25), 0 0 16px rgba(0,229,200,0.15);
    animation: highlightPulse 1.8s ease forwards;
  }
  @keyframes highlightPulse {
    0%   { border-color: var(--cyan); box-shadow: 0 0 0 3px rgba(0,229,200,0.4); }
    60%  { border-color: var(--cyan); box-shadow: 0 0 0 2px rgba(0,229,200,0.2); }
    100% { border-color: var(--border); box-shadow: none; }
  }
  .course-card.inactive { opacity: 0.45; }
  .course-card.conflict { border-color: rgba(255, 77, 109, 0.5) !important; }

  .card-top {
    display: flex;
    align-items: flex-start;
    gap: 8px;
    margin-bottom: 6px;
  }
  .card-toggle {
    width: 28px; height: 16px;
    background: var(--bg);
    border: 1px solid rgba(255,255,255,0.12);
    border-radius: 8px;
    cursor: pointer;
    position: relative;
    flex-shrink: 0;
    margin-top: 2px;
    transition: background 0.2s, border-color 0.2s;
  }
  .card-toggle::after {
    content: '';
    position: absolute;
    width: 10px; height: 10px;
    background: var(--muted);
    border-radius: 50%;
    top: 2px; left: 2px;
    transition: transform 0.2s, background 0.2s;
  }
  .card-toggle.on {
    background: rgba(0,229,200,0.15);
    border-color: var(--cyan);
  }
  .card-toggle.on::after {
    transform: translateX(12px);
    background: var(--cyan);
  }

  .card-info { flex: 1; min-width: 0; }
  .card-title {
    font-size: 12px;
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: 2px;
    color: var(--text);
    text-decoration: none;
    display: block;
    transition: color 0.15s;
  }
  .card-title:hover {
    color: var(--cyan);
    text-decoration: underline;
    text-underline-offset: 2px;
  }
  .card-meta {
    font-size: 10px;
    color: var(--muted);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }
  .card-id {
    font-family: var(--font-mono);
    font-size: 9px;
    color: var(--muted);
    opacity: 0.6;
  }

  .card-bottom {
    display: flex;
    align-items: center;
    gap: 8px;
  }
  .slot-pills {
    flex: 1;
    display: flex;
    flex-wrap: wrap;
    gap: 3px;
  }
  .slot-pill {
    font-family: var(--font-mono);
    font-size: 9px;
    padding: 2px 5px;
    border-radius: 3px;
    background: rgba(255,255,255,0.05);
    color: var(--muted);
    white-space: nowrap;
  }
  .slot-pill.conflict-pill {
    background: rgba(255, 77, 109, 0.15);
    color: var(--red);
  }
  .ects-wrap {
    display: flex;
    align-items: center;
    flex-shrink: 0;
  }
  .ects-static {
    font-family: var(--font-mono);
    font-size: 10px;
    color: var(--amber);
    background: rgba(240,165,0,0.08);
    border: 1px solid rgba(240,165,0,0.2);
    border-radius: 4px;
    padding: 2px 7px;
    white-space: nowrap;
  }
  .ects-static.empty {
    color: var(--muted);
    border-color: var(--border);
    background: transparent;
  }

  /* FOOTER OF LEFT PANEL */
  .left-footer {
    padding: 14px 18px;
    border-top: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
  }
  .total-section { display: flex; flex-direction: column; gap: 4px; }
  .total-label {
    font-family: var(--font-mono);
    font-size: 9px;
    letter-spacing: 1.5px;
    color: var(--muted);
    text-transform: uppercase;
  }
  .total-display {
    display: flex;
    align-items: baseline;
    gap: 6px;
  }
  .total-num {
    font-family: var(--font-mono);
    font-size: 32px;
    font-weight: 700;
    color: var(--amber);
    line-height: 1;
    transition: color 0.3s;
  }
  .total-unit {
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--muted);
  }
  .select-all-btn {
    font-size: 11px;
    padding: 6px 12px;
    background: rgba(255,255,255,0.04);
    border: 1px solid var(--border);
    border-radius: 5px;
    color: var(--muted);
    cursor: pointer;
    transition: all 0.2s;
    font-family: var(--font);
  }
  .select-all-btn:hover {
    border-color: rgba(255,255,255,0.15);
    color: var(--text);
  }

  /* RIGHT PANEL */
  .right-panel {
    display: flex;
    flex-direction: column;
    overflow: hidden;
    background: var(--bg);
  }
  .cal-header {
    display: grid;
    grid-template-columns: 48px repeat(5, 1fr);
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
  }
  .cal-header-cell {
    padding: 12px 8px;
    text-align: center;
    font-family: var(--font-mono);
    font-size: 10px;
    letter-spacing: 1px;
    color: var(--muted);
    text-transform: uppercase;
    border-right: 1px solid var(--border);
  }
  .cal-header-cell:last-child { border-right: none; }
  .cal-header-cell.today-col { color: var(--cyan); }
  .cal-header-spacer { border-right: 1px solid var(--border); }

  .cal-body {
    flex: 1;
    overflow: hidden;
    position: relative;
  }

  .cal-grid {
    display: grid;
    grid-template-columns: 48px repeat(5, 1fr);
    height: 100%;
    position: relative;
  }

  .time-col {
    position: relative;
    border-right: 1px solid var(--border);
  }
  .time-label {
    position: absolute;
    left: 0; right: 0;
    font-family: var(--font-mono);
    font-size: 9px;
    color: var(--muted);
    text-align: center;
    transform: translateY(-50%);
    padding-top: 2px;
  }
  .day-col {
    position: relative;
    border-right: 1px solid var(--border);
    height: 100%;
  }
  .day-col:last-child { border-right: none; }
  .hour-line {
    position: absolute;
    left: 0; right: 0;
    border-top: 1px solid var(--border);
  }
  .half-line {
    position: absolute;
    left: 0; right: 0;
    border-top: 1px dashed rgba(255,255,255,0.025);
  }

  .event-block {
    position: absolute;
    left: 3px; right: 3px;
    border-radius: 5px;
    padding: 4px 6px;
    overflow: hidden;
    cursor: default;
    transition: opacity 0.2s;
    z-index: 2;
  }
  .event-block:hover { z-index: 10; opacity: 0.9; }
  .event-block.conflict-block {
    outline: 1.5px solid var(--red) !important;
    outline-offset: 0;
  }
  .event-title {
    font-size: 9px;
    font-weight: 600;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    line-height: 1.3;
  }
  .event-sub {
    font-family: var(--font-mono);
    font-size: 8px;
    opacity: 0.7;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    margin-top: 1px;
  }

  /* Tooltip */
  .tooltip {
    display: none;
    position: fixed;
    background: var(--bg3);
    border: 1px solid rgba(255,255,255,0.15);
    border-radius: 8px;
    padding: 10px 12px;
    font-size: 11px;
    z-index: 1000;
    pointer-events: none;
    max-width: 220px;
    box-shadow: 0 8px 32px rgba(0,0,0,0.5);
  }
  .tooltip.show { display: block; }
  .tooltip-title { font-weight: 600; margin-bottom: 4px; font-size: 12px; }
  .tooltip-row { display: flex; gap: 6px; color: var(--muted); font-size: 10px; margin-top: 2px; }
  .tooltip-row span:first-child { color: var(--text); }

  /* Scrollbar neutral */
  .courses-list::-webkit-scrollbar { width: 3px; }
  .courses-list::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.08); }

  /* Color palette for courses - cycling */
  .course-color-0  { background: rgba( 0,229,200,0.12); border-left: 2.5px solid #00e5c8; }
  .course-color-1  { background: rgba(240,165, 0,0.12); border-left: 2.5px solid #f0a500; }
  .course-color-2  { background: rgba(130,100,255,0.14); border-left: 2.5px solid #8264ff; }
  .course-color-3  { background: rgba( 57,217,138,0.12); border-left: 2.5px solid #39d98a; }
  .course-color-4  { background: rgba(255,140, 60,0.12); border-left: 2.5px solid #ff8c3c; }
  .course-color-5  { background: rgba( 50,170,255,0.12); border-left: 2.5px solid #32aaff; }
  .course-color-6  { background: rgba(255, 80,160,0.12); border-left: 2.5px solid #ff50a0; }
  .course-color-7  { background: rgba(200,220, 50,0.12); border-left: 2.5px solid #c8dc32; }
  .course-color-8  { background: rgba(255,200, 80,0.12); border-left: 2.5px solid #ffc850; }
  .course-color-9  { background: rgba( 80,200,255,0.12); border-left: 2.5px solid #50c8ff; }
  .course-color-10 { background: rgba(160,255,120,0.12); border-left: 2.5px solid #a0ff78; }
  .course-color-11 { background: rgba(255,120,120,0.12); border-left: 2.5px solid #ff7878; }
  .course-color-12 { background: rgba( 60,120,255,0.12); border-left: 2.5px solid #3c78ff; }
  .course-color-13 { background: rgba(220, 80,220,0.12); border-left: 2.5px solid #dc50dc; }
  .course-color-14 { background: rgba( 80,220,200,0.12); border-left: 2.5px solid #50dcc8; }
  .course-color-15 { background: rgba(255,170, 50,0.12); border-left: 2.5px solid #ffaa32; }
  .course-color-16 { background: rgba(100,200,100,0.12); border-left: 2.5px solid #64c864; }
  .course-color-17 { background: rgba(255, 60, 60,0.12); border-left: 2.5px solid #ff3c3c; }
  .course-color-18 { background: rgba(100,160,255,0.12); border-left: 2.5px solid #64a0ff; }
  .course-color-19 { background: rgba(180,255,180,0.12); border-left: 2.5px solid #b4ffb4; }
  .course-color-20 { background: rgba(255,180,100,0.12); border-left: 2.5px solid #ffb464; }
  .course-color-21 { background: rgba(150, 80,255,0.12); border-left: 2.5px solid #9650ff; }
  .course-color-22 { background: rgba( 50,220,180,0.12); border-left: 2.5px solid #32dcb4; }
  .course-color-23 { background: rgba(255,220, 50,0.12); border-left: 2.5px solid #ffdc32; }
  .course-color-24 { background: rgba( 80,130,255,0.12); border-left: 2.5px solid #5082ff; }
  .course-color-25 { background: rgba(255,100,180,0.12); border-left: 2.5px solid #ff64b4; }
  .course-color-26 { background: rgba(100,255,200,0.12); border-left: 2.5px solid #64ffc8; }
  .course-color-27 { background: rgba(200,150,255,0.12); border-left: 2.5px solid #c896ff; }
  .course-color-28 { background: rgba(255,150, 50,0.12); border-left: 2.5px solid #ff9632; }
  .course-color-29 { background: rgba( 50,200,255,0.12); border-left: 2.5px solid #32c8ff; }

  /* dot colors for event blocks (matching border colors) */
  .ec-0  { background-color: rgba(0,229,200,0.18); }
  .ec-1  { background-color: rgba(240,165,0,0.18); }
  .ec-2  { background-color: rgba(130,100,255,0.20); }
  .ec-3  { background-color: rgba(57,217,138,0.18); }
  .ec-4  { background-color: rgba(255,140,60,0.18); }
  .ec-5  { background-color: rgba(50,170,255,0.18); }
  .ec-6  { background-color: rgba(255,80,160,0.18); }
  .ec-7  { background-color: rgba(200,220,50,0.18); }
  .ec-8  { background-color: rgba(255,200,80,0.18); }
  .ec-9  { background-color: rgba(80,200,255,0.18); }
  .ec-10 { background-color: rgba(160,255,120,0.18); }
  .ec-11 { background-color: rgba(255,120,120,0.18); }
  .ec-12 { background-color: rgba(60,120,255,0.18); }
  .ec-13 { background-color: rgba(220,80,220,0.18); }
  .ec-14 { background-color: rgba(80,220,200,0.18); }
  .ec-15 { background-color: rgba(255,170,50,0.18); }
  .ec-16 { background-color: rgba(100,200,100,0.18); }
  .ec-17 { background-color: rgba(255,60,60,0.18); }
  .ec-18 { background-color: rgba(100,160,255,0.18); }
  .ec-19 { background-color: rgba(180,255,180,0.18); }
  .ec-20 { background-color: rgba(255,180,100,0.18); }
  .ec-21 { background-color: rgba(150,80,255,0.18); }
  .ec-22 { background-color: rgba(50,220,180,0.18); }
  .ec-23 { background-color: rgba(255,220,50,0.18); }
  .ec-24 { background-color: rgba(80,130,255,0.18); }
  .ec-25 { background-color: rgba(255,100,180,0.18); }
  .ec-26 { background-color: rgba(100,255,200,0.18); }
  .ec-27 { background-color: rgba(200,150,255,0.18); }
  .ec-28 { background-color: rgba(255,150,50,0.18); }
  .ec-29 { background-color: rgba(50,200,255,0.18); }

  .border-c-0  { border-left-color: #00e5c8; }
  .border-c-1  { border-left-color: #f0a500; }
  .border-c-2  { border-left-color: #8264ff; }
  .border-c-3  { border-left-color: #39d98a; }
  .border-c-4  { border-left-color: #ff8c3c; }
  .border-c-5  { border-left-color: #32aaff; }
  .border-c-6  { border-left-color: #ff50a0; }
  .border-c-7  { border-left-color: #c8dc32; }
  .border-c-8  { border-left-color: #ffc850; }
  .border-c-9  { border-left-color: #50c8ff; }
  .border-c-10 { border-left-color: #a0ff78; }
  .border-c-11 { border-left-color: #ff7878; }
  .border-c-12 { border-left-color: #3c78ff; }
  .border-c-13 { border-left-color: #dc50dc; }
  .border-c-14 { border-left-color: #50dcc8; }
  .border-c-15 { border-left-color: #ffaa32; }
  .border-c-16 { border-left-color: #64c864; }
  .border-c-17 { border-left-color: #ff3c3c; }
  .border-c-18 { border-left-color: #64a0ff; }
  .border-c-19 { border-left-color: #b4ffb4; }
  .border-c-20 { border-left-color: #ffb464; }
  .border-c-21 { border-left-color: #9650ff; }
  .border-c-22 { border-left-color: #32dcb4; }
  .border-c-23 { border-left-color: #ffdc32; }
  .border-c-24 { border-left-color: #5082ff; }
  .border-c-25 { border-left-color: #ff64b4; }
  .border-c-26 { border-left-color: #64ffc8; }
  .border-c-27 { border-left-color: #c896ff; }
  .border-c-28 { border-left-color: #ff9632; }
  .border-c-29 { border-left-color: #32c8ff; }

  .save-load-row {
    display: flex;
    gap: 6px;
    margin-top: 8px;
  }
  .save-load-btn {
    flex: 1;
    padding: 7px 0;
    border: 1px solid var(--border);
    border-radius: 7px;
    background: var(--surface2);
    color: var(--text);
    font-size: 11px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.15s, border-color 0.15s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 4px;
    letter-spacing: 0.02em;
  }
  .save-load-btn:hover { background: var(--surface3); border-color: var(--cyan); color: var(--cyan); }
  .save-load-btn.load-btn:hover { border-color: var(--green); color: var(--green); }
  #jsonLoadInput { display: none; }

  /* Toast notification */
  .toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(20px);
    background: var(--surface3);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 10px 20px;
    font-size: 13px;
    color: var(--text);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s, transform 0.2s;
    z-index: 9999;
    white-space: nowrap;
  }
  .toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
  }

  /* Responsive adjustments */
  @media (max-width: 900px) {
    main { grid-template-columns: 280px 1fr; }
  }