* { box-sizing: border-box; }
:root {
  --primary: #5b3cc4;
  --primary-light: #eee9ff;
  --background: #f6f7fb;
  --surface: #ffffff;
  --text: #1d2330;
  --muted: #697386;
  --border: #e4e7ec;
  --success: #14804a;
  --warning: #b7791f;
  --danger: #c53030;
}

body {
  margin: 0;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--background);
  color: var(--text);
}

.topbar {
  height: 72px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 30px;
  position: sticky;
  top: 0;
  z-index: 20;
}

.brand { display: flex; align-items: center; gap: 12px; }
.logo {
  width: 40px; height: 40px; border-radius: 12px;
  background: var(--primary); color: white;
  display: grid; place-items: center; font-weight: 800;
}
.brand strong { display: block; font-size: 16px; }
.brand span { display: block; font-size: 12px; color: var(--muted); }

nav { display: flex; gap: 6px; }
.nav-link {
  border: 0; background: transparent; padding: 10px 18px;
  border-radius: 9px; cursor: pointer; color: var(--muted);
  font-size: 14px; font-weight: 650;
}
.nav-link:hover, .nav-link.active { background: var(--primary-light); color: var(--primary); }

.container { max-width: 1250px; margin: 0 auto; padding: 30px; }
.page-header { display:flex; justify-content:space-between; align-items:flex-start; gap:20px; margin-bottom:22px; }
h1 { margin: 0 0 5px; font-size: 28px; }
h2 { margin: 0; font-size: 19px; }
.subtitle { color: var(--muted); margin: 0; }

.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 14px; padding: 20px; box-shadow: 0 3px 14px rgba(30,35,48,.035);
}
.toolbar { display:flex; gap:10px; flex-wrap:wrap; align-items:center; }
input, select, button { font: inherit; }
input[type="date"], .search {
  border: 1px solid var(--border); border-radius: 9px; padding: 10px 12px;
  background: white; color: var(--text);
}
.search { width: 250px; }

.btn {
  border: 0; border-radius: 9px; padding: 10px 14px; cursor:pointer; font-weight:700;
}
.btn-primary { background: var(--primary); color:white; }
.btn-secondary { background: var(--primary-light); color:var(--primary); }
.btn-success { background:#e5f7ed; color:var(--success); }
.btn-small { padding: 7px 11px; font-size: 12px; }

.stats { display:grid; grid-template-columns: repeat(4, 1fr); gap:14px; margin-bottom:18px; }
.stat .label { color:var(--muted); font-size:12px; }
.stat .value { font-size:26px; font-weight:800; margin-top:4px; }

.student-list { display:flex; flex-direction:column; }
.student-row {
  display:grid; grid-template-columns: 1fr auto auto;
  gap:15px; align-items:center; padding:14px 4px;
  border-bottom:1px solid var(--border);
}
.student-row:last-child { border-bottom:0; }
.student-name { font-weight:750; }
.student-id { color:var(--muted); font-size:12px; margin-top:3px; }
.status { font-size:12px; font-weight:700; }
.status.present { color:var(--success); }
.status.absent { color:var(--muted); }

.calendar-layout { display:grid; grid-template-columns: 1.25fr .75fr; gap:18px; }
.calendar-head { display:flex; justify-content:space-between; align-items:center; margin-bottom:15px; }
.calendar-title { font-weight:800; }
.calendar-grid { display:grid; grid-template-columns:repeat(7,1fr); gap:5px; }
.day-name { text-align:center; font-size:11px; color:var(--muted); padding:7px 0; font-weight:700; }
.day {
  min-height:76px; border:1px solid var(--border); border-radius:9px;
  background:white; padding:7px; cursor:pointer;
}
.day:hover { border-color:var(--primary); }
.day.selected { outline:2px solid var(--primary); background:var(--primary-light); }
.day.muted { opacity:.4; }
.day-number { font-size:12px; font-weight:750; }
.dot { margin-top:10px; font-size:10px; color:var(--success); }
.day-details { min-height:300px; }
.attendance-item { padding:12px 0; border-bottom:1px solid var(--border); }
.attendance-item:last-child { border-bottom:0; }
.time { color:var(--muted); font-size:12px; margin-top:4px; }

.student-detail { display:grid; grid-template-columns: .8fr 1.2fr; gap:18px; }
.profile-row { display:flex; justify-content:space-between; gap:15px; padding:10px 0; border-bottom:1px solid var(--border); }
.profile-row span { color:var(--muted); font-size:13px; }
.profile-row strong { text-align:right; font-size:13px; }

.empty { padding:35px; text-align:center; color:var(--muted); }
.back { margin-bottom:15px; }

.toast {
  position:fixed; right:22px; bottom:22px; background:#1d2330; color:white;
  padding:12px 16px; border-radius:10px; transform:translateY(100px);
  opacity:0; transition:.25s; z-index:50; font-size:13px;
}
.toast.show { transform:translateY(0); opacity:1; }

@media (max-width: 850px) {
  .topbar { padding: 0 16px; }
  .container { padding: 20px 15px; }
  .stats { grid-template-columns:repeat(2,1fr); }
  .calendar-layout, .student-detail { grid-template-columns:1fr; }
}
@media (max-width: 560px) {
  .topbar { height:auto; min-height:72px; flex-wrap:wrap; gap:8px; padding:12px 15px; }
  nav { width:100%; }
  .nav-link { flex:1; }
  .student-row { grid-template-columns:1fr auto; }
  .student-row .status { grid-column:1; }
  .search { width:100%; }
}