:root{
  --bg: #0b0e14;
  --panel: #111520;
  --muted: #222838;
  --text: #e6e8ed;
  --subtle: #a8b0c2;
  --accent: #6366f1;
  --accent-2: #22c55e;
  --danger: #ef4444;
  --grid-line: #1f2535;
  --slot-height: 56px; /* height per hour */
  --slot-subdiv: 2;    /* 2 => 30-minute rows */
  --radius: 14px;
  --shadow: 0 10px 30px rgba(0,0,0,.25), inset 0 0 0 1px rgba(255,255,255,.03);
  --col-gap: 10px;
}

*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Inter, "Helvetica Neue", Arial, "Noto Sans";
  color:var(--text);
  background: linear-gradient(180deg, #0b0e14, #0b0e14 60%, #0d1019);
}

.app-header, .app-footer{
  display:flex; align-items:center; justify-content:space-between;
  padding:18px 22px;
  position:sticky; top:0; z-index:10;
  background:transparent;
  backdrop-filter:saturate(120%) blur(8px);
}
.app-header h1{ font-size:clamp(18px, 2.2vw, 28px); margin:0; letter-spacing:.3px; }
.header-actions { display:flex; gap:10px; align-items:center; flex-wrap:wrap; }
.share-group { display:flex; gap:10px; align-items:center; flex-wrap:wrap; }
#fileInput{ position:absolute; width:1px; height:1px; padding:0; margin:-1px; overflow:hidden; border:0; clip:rect(0 0 0 0); }

.container{ max-width:1200px; margin: 0 auto; padding: 8px 16px 40px; }

.legend{ display:flex; gap:20px; align-items:center; padding:10px 4px 18px; color:var(--subtle); font-size:14px; }
.legend .dot{ display:inline-block; width:10px; height:10px; border-radius:50%; background:var(--accent); margin-right:8px; }
.legend .dot.outline{ background:transparent; border:2px solid var(--subtle) }

.schedule-wrapper{ overflow:auto; background:var(--panel); border-radius:var(--radius); box-shadow: var(--shadow); border:1px solid #151b2a; }

/* Grid: 1 time column + 7 day columns */
.schedule-grid{ display:grid; grid-template-columns: 90px repeat(7, 1fr); gap: var(--col-gap); min-width: 900px; }

/* Header row (days) */
.day-header{ position:sticky; top:0; z-index:5; background:linear-gradient(180deg, rgba(17,21,32,.96), rgba(17,21,32,.84)); padding:12px 10px; border-bottom:1px solid #1a2132; font-weight:600; text-align:center; letter-spacing:.3px; }

/* Time column */
.time-col{ padding-top:56px; border-right:1px dashed #1a2132; }
.time-label{ height: var(--slot-height); position:relative; color:var(--subtle); font-size:12px; }
.time-label span{ position:absolute; top:-7px; right:12px; }

/* Day columns */
.day-col{
  position:relative;
  padding-top:56px;
  min-height: calc((var(--slot-height)) * 12);
  background:
    repeating-linear-gradient(
      to bottom,
      transparent 0,
      transparent calc(var(--slot-height) / var(--slot-subdiv) - 1px),
      var(--grid-line) calc(var(--slot-height) / var(--slot-subdiv) - 1px),
      var(--grid-line) calc(var(--slot-height) / var(--slot-subdiv))
    );
  border-left:1px solid #141a29;
}

/* Class blocks */
.class-block{
  position:absolute; left:8px; right:8px;
  padding:10px 12px; border-radius:12px; background:var(--accent); color:white;
  box-shadow: 0 6px 18px rgba(0,0,0,.3), inset 0 0 0 1px rgba(255,255,255,.15);
  cursor:pointer; user-select:none; overflow:hidden; display:flex; flex-direction:column; gap:4px;
}
.class-title{ font-weight:700; font-size:13px; line-height:1.2; letter-spacing:.2px; text-shadow: 0 1px 0 rgba(0,0,0,.15); }
.class-meta{ font-size:12px; opacity:.95; display:flex; gap:8px; flex-wrap:wrap; }

/* Overlap lanes */
.class-block.lane-0{ left:8px }
.class-block.lane-1{ left:8px; right:54% }
.class-block.lane-2{ left:8px; right:66% }
.class-block.lane-3{ left:8px; right:75% }

/* Buttons */
.btn{ appearance:none; border:none; cursor:pointer; border-radius:10px; padding:10px 14px; font-weight:600; background:#1b2233; color:var(--text); box-shadow: inset 0 0 0 1px #2b3550; }
.btn:hover{ filter:brightness(1.05) } .btn:active{ transform:translateY(1px) }
.btn-primary{ background: linear-gradient(180deg, #6b72ff, #4f46e5); color:#fff; box-shadow: inset 0 0 0 1px rgba(255,255,255,.2) }
.btn-ghost{ background:transparent; box-shadow: inset 0 0 0 1px #2b3550; color:var(--subtle) }
.btn-danger{ background: linear-gradient(180deg, #ff6b6b, #ef4444); color:#fff }

.icon-btn{ background:transparent; border:none; color:var(--subtle); font-size:18px; cursor:pointer; line-height:1; }

/* Modals */
.modal{ border:none; padding:0; background: transparent; }
.modal::backdrop{ background: rgba(0,0,0,.6); backdrop-filter: blur(2px); }
.modal-card{ width:min(720px, 92vw); background:var(--panel); color:var(--text); border-radius:16px; box-shadow: var(--shadow); border:1px solid #151b2a; overflow:hidden; }
.modal-header, .modal-footer{ display:flex; align-items:center; justify-content:space-between; padding:14px 16px; background: linear-gradient(180deg, #121829, #121829f2); border-bottom:1px solid #1a2132; }
.modal-footer{ border-top:1px solid #1a2132; border-bottom:none; background:#111520; gap:10px; justify-content:flex-end; }
.modal-body{ padding:16px; display:grid; gap:16px; }

/* Forms */
.form-row{ display:flex; flex-direction:column; gap:8px }
.form-grid{ display:grid; gap:14px; grid-template-columns: repeat(3, 1fr); }
fieldset.days-fieldset{ border:1px dashed #2b3550; border-radius:12px; padding:10px 12px }
fieldset legend{ padding:0 6px; color:var(--subtle) }
.days{ display:flex; flex-wrap:wrap; gap:12px; padding-top:6px }
label{ font-size:14px; color:var(--subtle) }
input[type="text"], input[type="time"], input[type="color"]{ width:100%; padding:10px 12px; border-radius:10px; border:1px solid #2b3550; background:#0f1422; color:var(--text); outline: none; }
input[type="time"]{ font-feature-settings: "tnum" on, "lnum" on }
.req{ color:#ffafaf } .help-text{ color:#eab308; min-height:1.2em; font-size:13px }

.details-grid{ display:grid; gap:10px; grid-template-columns: repeat(2, minmax(0, 1fr)); font-size:15px; }
.app-footer{ color:var(--subtle); border-top: 1px solid #121827; }

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

/* Responsive */
@media (max-width: 880px){
  .form-grid{ grid-template-columns: 1fr; }
  .details-grid{ grid-template-columns: 1fr; }
}