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

      :root {
        /* Dark theme (default) */
        --bg: #0f172a;
        --bg-alt: #111c2f;
        --panel: #132035;
        --panel-accent: #182a42;
        --panel-accent-2: #1d3654;
        --border: #24324a;
        --border-strong: #2a3e57;
        --text: #f1f5f9;
        --text-soft: #94a3b8;
        --tag-bg: #15263b;
        --tag-bg-focus: #1b314d;
        --input-bg: #0f1c2b;
        --input-bg-focus: #14263a;
        --scroll-track: #1e293b;
        --scroll-thumb: #334155;
        --primary-grad-a: #2563eb;
        --primary-grad-b: #1d4ed8;
        --primary-grad-hover-a: #1d4ed8;
        --primary-grad-hover-b: #1e40af;
        --danger: #991b1b;
        --danger-hover: #b91c1c;
        --success-bg: #052e16;
        --success-text: #16a34a;
        --success-border: #14532d;
        --error-bg: #450a0a;
        --error-text: #f87171;
        --error-border: #7f1d1d;
        --info-bg: #1e3a8a;
        --info-text: #93c5fd;
        --info-border: #1d4ed8;
        --warning-bg: #3f2d15;
        --warning-text: #fcd34d;
        --warning-border: #b45309;
        --file-bg: #1e293b;
        --file-border: #2a3e57;
        --file-text: var(--text);
        --file-accent: var(--primary-grad-a);
      }

      body.light-theme {
        --bg: #f5f7fb;
        --bg-alt: #ffffff;
        --panel: #ffffff;
        --panel-accent: #eef3f9;
        --panel-accent-2: #e3edf7;
        --border: #d8e2ee;
        --border-strong: #c4d3e3;
        --text: #1e293b;
        --text-soft: #64748b;
        --tag-bg: #f1f5f9;
        --tag-bg-focus: #e2e8f0;
        --input-bg: #ffffff;
        --input-bg-focus: #f1f5f9;
        --scroll-track: #e2e8f0;
        --scroll-thumb: #cbd5e1;
        --primary-grad-a: #2563eb;
        --primary-grad-b: #1d4ed8;
        --primary-grad-hover-a: #1d4ed8;
        --primary-grad-hover-b: #1e40af;
        --danger: #dc2626;
        --danger-hover: #b91c1c;
        --success-bg: #dcfce7;
        --success-text: #15803d;
        --success-border: #86efac;
        --error-bg: #fee2e2;
        --error-text: #dc2626;
        --error-border: #fca5a5;
        --info-bg: #dbeafe;
        --info-text: #1d4ed8;
        --info-border: #93c5fd;
        --warning-bg: #fef3c7;
        --warning-text: #b45309;
        --warning-border: #fcd34d;
        --file-bg: #f1f5f9;
        --file-border: #d8e2ee;
        --file-text: #1e293b;
        --file-accent: #2563eb;
      }

      body {
        font-family: "Segoe UI", system-ui, Tahoma, Geneva, Verdana, sans-serif;
        background: var(--bg);
        min-height: 100vh;
        padding: 0;
        color: var(--text);
        transition: background .4s, color .4s;
      }

      .container {
        width: 100%;
        margin: 0;
        background: transparent;
        border-radius: 0;
        box-shadow: none;
      }

      .header {
        background: var(--bg-alt);
        color: var(--text);
        padding: 32px 48px;
        display:flex;
        flex-direction:column;
        gap:6px;
        border-bottom:1px solid #1e293b;
      }

      .header h1 {
        font-size: 2.5rem;
        margin-bottom: 10px;
      }

      .header p {
        opacity: 0.9;
        font-size: 1.1rem;
      }

      .content {
        padding: 32px 48px 80px;
        width:100%;
        box-sizing:border-box;
      }

      .section {
        margin-bottom: 32px;
        border: 1px solid var(--border);
        border-radius: 12px;
        background: var(--panel);
        backdrop-filter: blur(4px);
        box-shadow: 0 4px 12px rgba(0,0,0,0.15);
        transition: border-color .25s, transform .25s, background .4s;
      }
      .section:hover { border-color: var(--border-strong); transform: translateY(-2px); }

      .section-header {
        background: linear-gradient(90deg,var(--panel-accent),var(--panel-accent-2));
        padding: 18px 22px;
        border-bottom: 1px solid var(--border);
        transition: background .4s;
      }

      .section-header h2 {
        color: var(--text);
        display:flex;
        align-items:center;
        gap:10px;
        font-size:1.1rem;
        font-weight:600;
        letter-spacing:.5px;
        text-transform:uppercase;
      }

      .section-content {
        padding: 22px 24px 26px;
      }

      .textarea-container {
        position: relative;
        margin-bottom: 15px;
      }

  .codigo-tags-container { display:flex; flex-wrap:wrap; gap:8px; min-height:52px; padding:14px 16px 10px; border:1px solid var(--border); border-radius:10px; background:var(--tag-bg); margin-bottom:18px; transition:border-color .25s, background .25s; }
  .codigo-tags-container:focus-within { border-color:var(--primary-grad-a); background:var(--tag-bg-focus); }

  .codigo-tag { background: linear-gradient(135deg,var(--primary-grad-a),var(--primary-grad-b)); color:#fff;
        padding:6px 14px 6px 12px;
        border-radius:22px;
        font-size:12px;
        font-weight:500;
        display:flex;
        align-items:center;
        gap:6px;
        line-height:1.2;
        position:relative;
        box-shadow:0 2px 4px rgba(0,0,0,.35);
        transition:background .25s, transform .25s;
      }

  .codigo-tag:hover { background:linear-gradient(135deg,var(--primary-grad-hover-a),var(--primary-grad-hover-b)); transform:translateY(-2px); }

      .codigo-tag .remove-codigo {
        background:rgba(255,255,255,0.18);
        border:none;
        color:#fff;
        padding:2px 7px 3px;
        border-radius:12px;
        cursor:pointer;
        font-size:10px;
        line-height:1;
        font-weight:600;
        letter-spacing:.5px;
        transition:background .25s, transform .25s;
      }

      .codigo-tag .remove-codigo:hover {
        background:rgba(255,255,255,0.35);
        transform:scale(1.1);
      }

      .codigo-input-row {
        display:flex;
        align-items:center;
        gap:10px;
        margin-bottom:10px;
        flex-wrap:wrap;
      }

  .codigo-input { flex:1; padding:10px 14px; border:1px solid var(--border-strong); border-radius:8px; font-size:14px; background:var(--input-bg); color:var(--text); transition:border-color .25s, background .25s; }
  .codigo-input:focus { outline:none; border-color:var(--primary-grad-a); background:var(--input-bg-focus); }

  .btn-add-codigo { background:linear-gradient(135deg,var(--primary-grad-a),var(--primary-grad-b)); color:#fff;
        border:none;
        padding:10px 16px;
        border-radius:8px;
        cursor:pointer;
        font-size:13px;
        font-weight:600;
        transition:background .25s, transform .25s, box-shadow .25s;
        white-space:nowrap;
        letter-spacing:.4px;
      }

  .btn-add-codigo:hover { background:linear-gradient(135deg,var(--primary-grad-hover-a),var(--primary-grad-hover-b)); transform:translateY(-2px); box-shadow:0 4px 14px rgba(37,99,235,.35); }

  .empty-state { color:var(--text-soft); font-style:italic; padding:18px; text-align:center; border:1px dashed var(--border-strong); background:var(--tag-bg); border-radius:10px; margin-bottom:16px; font-size:13px; }

  textarea { width:100%; min-height:120px; padding:14px 16px; border:1px solid var(--border-strong); border-radius:10px; font-family:"Courier New", monospace; font-size:14px; resize:vertical; background:var(--input-bg); color:var(--text); transition:border-color .25s, background .25s; }
  textarea:focus { outline:none; border-color:var(--primary-grad-a); background:var(--input-bg-focus); }

  .help-text { font-size:11px; color:var(--text-soft); margin-top:4px; margin-bottom:6px; letter-spacing:.3px; }

  .btn { background:linear-gradient(135deg,#334155,#1e293b); color:var(--text); border:1px solid var(--border-strong); padding:11px 22px; border-radius:10px; cursor:pointer; font-size:13px; font-weight:600; transition:background .25s, box-shadow .25s, transform .25s, border-color .25s; margin-right:10px; letter-spacing:.4px; }
  body.light-theme .btn { background:linear-gradient(135deg,#e2e8f0,#cbd5e1); color:#1e293b; }
  .btn:hover { border-color:var(--primary-grad-a); background:linear-gradient(135deg,#1e293b,#0f172a); transform:translateY(-2px); box-shadow:0 6px 18px -4px rgba(0,0,0,.4), 0 0 0 1px rgba(59,130,246,.15); }
  body.light-theme .btn:hover { background:linear-gradient(135deg,#cbd5e1,#94a3b8); }
  .btn.secondary { background:linear-gradient(135deg,#475569,#334155); }
  body.light-theme .btn.secondary { background:linear-gradient(135deg,#e5e7eb,#d1d5db); }

  .btn-success { background: linear-gradient(135deg,#15803d,#166534); border-color:#166534; }
  .btn-success:hover { background: linear-gradient(135deg,#166534,#14532d); box-shadow:0 6px 18px -4px rgba(22,101,52,.55); }

      .status {
        padding:14px 16px;
        border-radius:10px;
        margin-top:14px;
        display:none;
        font-size:13px;
        font-weight:500;
        letter-spacing:.3px;
        border:1px solid transparent;
      }

  .status.success { background:var(--success-bg); color:var(--success-text); border-color:var(--success-border); }
  .status.error { background:var(--error-bg); color:var(--error-text); border-color:var(--error-border); }
  .status.info { background:var(--info-bg); color:var(--info-text); border-color:var(--info-border); }

      .grid {
        display:grid;
        grid-template-columns:repeat(auto-fit,minmax(370px,1fr));
        gap:34px;
        align-items:start;
      }

      .horarios-grid {
        display:grid;
        grid-template-columns:repeat(auto-fit,minmax(110px,1fr));
        gap:12px;
        margin-bottom:18px;
      }

  .horario-tag { background:#1e293b; border:1px solid #32455e;
        padding:8px 12px;
        border-radius:18px;
        text-align:center;
        font-weight:500;
        transition:background .25s, color .25s, border-color .25s, transform .25s;
        display:flex;
        align-items:center;
        justify-content:space-between;
        gap:8px;
        min-width:120px;
        color:#cbd5e1;
      }

      .horario-tag:hover {
        background:#2563eb;
        color:#fff;
        border-color:#1d4ed8;
        transform:translateY(-2px);
      }

      .horario-tag .time-text {
        flex: 1;
      }

      .horario-tag .btn-remove-tag {
        background:#991b1b;
        color:#fff;
        border:none;
        padding:3px 8px 4px;
        border-radius:12px;
        cursor:pointer;
        font-size:10px;
        opacity:0;
        transition:background .25s, transform .25s, opacity .25s;
        line-height:1;
        font-weight:600;
        letter-spacing:.5px;
      }

      .horario-tag:hover .btn-remove-tag {
        opacity: 1;
      }

      .horario-tag .btn-remove-tag:hover {
        background:#b91c1c;
        transform:scale(1.1);
      }

  .horario-input-row { display:flex; align-items:center; gap:16px; margin-bottom:16px; padding:18px 20px; background:var(--tag-bg); border-radius:14px; border:1px solid var(--border); flex-wrap:nowrap; max-width:fit-content; transition:background .4s, border-color .4s; }
  body.light-theme .horario-input-row { background:var(--tag-bg); border-color:var(--border); }

  .time-select { padding:10px 14px; border:1px solid var(--border-strong); border-radius:8px; font-size:14px; background:var(--input-bg); color:var(--text); min-width:70px; flex-shrink:0; transition:border-color .25s, background .25s; }
  .time-select:focus { outline:none; border-color:var(--primary-grad-a); background:var(--input-bg-focus); }

      .btn-remove {
        background:#991b1b;
        color:#fff;
        border:none;
        padding:8px 14px;
        border-radius:8px;
        cursor:pointer;
        font-size:11px;
        font-weight:600;
        transition:background .25s, transform .25s;
        letter-spacing:.5px;
      }

      .btn-remove:hover {
        background:#b91c1c;
        transform:translateY(-2px);
      }

      .btn-add {
        background:linear-gradient(135deg,#2563eb,#1d4ed8);
        color:#fff;
        border:none;
        padding:10px 20px;
        border-radius:10px;
        cursor:pointer;
        font-size:13px;
        font-weight:600;
        transition:background .25s, transform .25s, box-shadow .25s;
        margin-left:10px;
        white-space:nowrap;
        letter-spacing:.4px;
      }

      .btn-add:hover {
        background:linear-gradient(135deg,#1d4ed8,#1e40af);
        transform:translateY(-2px);
        box-shadow:0 4px 14px rgba(37,99,235,.35);
      }

      .horarios-input-container {
        margin-bottom: 20px;
      }

  .unsaved-warning { background:var(--warning-bg); color:var(--warning-text); border:1px solid var(--warning-border);
        padding:12px 16px;
        border-radius:10px;
        margin-bottom:14px;
        display:none;
        font-size:13px;
        font-weight:500;
        letter-spacing:.3px;
      }

      .unsaved-warning.show {
        display:block;
        animation:fadeIn .3s ease-in;
      }

      @keyframes fadeIn {
        from {
          opacity: 0;
          transform: translateY(-10px);
        }
        to {
          opacity: 1;
          transform: translateY(0);
        }
      }

      .horario-input-row span {
  font-weight: 500;
  color: var(--text);
  white-space: nowrap;
      }

      .horario-input-row .separator {
        font-size: 18px;
        font-weight: bold;
        color: #667eea;
      }

      @media (max-width: 1100px) {
        .content { padding:28px 32px 72px; }
        .header { padding:28px 32px; }
      }
      @media (max-width: 768px) {
        .content { padding:24px 20px 60px; }
        .header { padding:24px 20px; }
        .header h1 { font-size:1.9rem; }
        .horario-input-row { flex-wrap:wrap; max-width:100%; gap:12px; }
        .horario-input-row span { flex-basis:100%; margin-bottom:4px; }
      }

      .loading {
        display: inline-block;
        width: 20px;
        height: 20px;
        border: 3px solid #f3f3f3;
        border-top: 3px solid #667eea;
        border-radius: 50%;
        animation: spin 1s linear infinite;
        margin-left: 10px;
      }

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

      /* Scrollable area specifically for the celdas tags list */
      #celdas-tags-container {
        max-height:230px;
        overflow-y:auto;
        padding-right:6px;
        scrollbar-gutter:stable both-edges;
      }

      /* Subtle custom scrollbar (webkit browsers) */
      #celdas-tags-container::-webkit-scrollbar {
        width: 8px;
      }
  #celdas-tags-container::-webkit-scrollbar-track { background: var(--scroll-track); border-radius: 10px; }
  #celdas-tags-container::-webkit-scrollbar-thumb { background: var(--scroll-thumb); border-radius: 10px; transition: background .3s; }
  #celdas-tags-container::-webkit-scrollbar-thumb:hover { background: var(--primary-grad-a); }

  /* Theme toggle */
  .btn-theme-toggle { background:linear-gradient(135deg,var(--primary-grad-a),var(--primary-grad-b)); color:#fff; border:none; padding:10px 18px; border-radius:30px; cursor:pointer; font-size:13px; font-weight:600; letter-spacing:.5px; box-shadow:0 4px 14px rgba(0,0,0,.35); transition:transform .25s, box-shadow .3s, background .4s; }
  .btn-theme-toggle:hover { transform:translateY(-2px); box-shadow:0 8px 22px -6px rgba(0,0,0,.5); }
  body.light-theme .btn-theme-toggle { background:linear-gradient(135deg,#1d4ed8,#2563eb); }

  /* Custom file input */
  .import-group { margin:8px 0 16px; display:flex; flex-wrap:wrap; gap:12px; align-items:center; }
  .import-label { font-size:12px; font-weight:600; color:var(--text); opacity:.85; }
  body.light-theme .import-label { color:#1e293b; }
  .file-input-wrapper { position:relative; display:inline-flex; align-items:center; gap:10px; }
  .file-input { position:absolute; inset:0; opacity:0; cursor:pointer; width:180px; }
  .file-input-label { background:var(--file-bg); color:var(--file-text); border:1px solid var(--file-border); padding:10px 18px; border-radius:10px; font-size:12px; font-weight:600; cursor:pointer; display:inline-flex; align-items:center; gap:6px; letter-spacing:.4px; box-shadow:0 2px 6px rgba(0,0,0,.25); transition:background .25s, transform .25s, border-color .25s; }
  .file-input-label:hover { background:var(--tag-bg-focus); border-color:var(--primary-grad-a); transform:translateY(-2px); }
  body.light-theme .file-input-label { background:#ffffff; box-shadow:0 2px 6px rgba(0,0,0,.08); }
  body.light-theme .file-input-label:hover { background:#f1f5f9; }
  .file-chosen { font-size:12px; font-weight:500; color:var(--text-soft); min-width:60px; background:var(--tag-bg); padding:8px 12px; border-radius:8px; border:1px solid var(--border); display:inline-block; max-width:200px; white-space:nowrap; overflow:hidden; text-overflow:ellipsis; }
  body.light-theme .file-chosen { background:#f1f5f9; }
  .import-btn { padding:8px 16px !important; font-size:12px !important; }

  /* Light theme specific adjustments */
  body.light-theme .section { box-shadow:0 4px 14px rgba(0,0,0,.08); }
  body.light-theme .codigo-tags-container { background:var(--tag-bg); }
  body.light-theme .codigo-tags-container:focus-within { background:var(--tag-bg-focus); }
  body.light-theme .empty-state { background:#f1f5f9; }
  body.light-theme .horario-tag { background:#f1f5f9; border-color:#d8e2ee; color:#1e293b; }
  body.light-theme .horario-tag:hover { background:var(--primary-grad-a); color:#fff; }
  body.light-theme .unsaved-warning { background:#fef3c7; color:#b45309; }

  /* Días container theme-aware */
  .dias-container { margin-top:8px; background:var(--tag-bg); border-radius:12px; padding:16px 18px; box-shadow:0 2px 8px rgba(0,0,0,0.25); border:1px solid var(--border); max-width:360px; transition:background .4s, border-color .4s, box-shadow .4s; }
  body.light-theme .dias-container { background:#ffffff; box-shadow:0 2px 8px rgba(0,0,0,0.06); }
  .dias-inner { display:flex; align-items:center; gap:14px; }
  .dias-label { font-weight:600; font-size:13px; color:var(--text); }
  body.light-theme .dias-label { color:#1e293b; }
  .dias-number { width:100px !important; }