:root {
  color-scheme: light;
  --bg: #f5f7fb;
  --panel: #ffffff;
  --text: #172033;
  --muted: #657085;
  --border: #e2e7f0;
  --primary: #1f6feb;
  --primary-dark: #1858bc;
  --danger: #d1242f;
  --shadow: 0 18px 55px rgba(23, 32, 51, 0.08);
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
}
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: center;
  padding: 14px clamp(16px, 5vw, 52px);
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.brand { font-size: 20px; font-weight: 800; color: var(--text); }
.nav { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.user { color: var(--muted); font-size: 14px; }
.container { width: min(1180px, calc(100% - 28px)); margin: 28px auto 70px; }

.hero {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  align-items: end;
  margin-bottom: 20px;
}
h1 { margin: 0 0 8px; font-size: clamp(28px, 4vw, 42px); letter-spacing: -0.03em; }
.muted { color: var(--muted); margin: 0; }
.stats { display: flex; gap: 12px; }
.stats div {
  min-width: 110px;
  padding: 16px;
  border-radius: 18px;
  background: var(--panel);
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}
.stats strong { display: block; font-size: 26px; }
.stats span { color: var(--muted); font-size: 14px; }

.panel, .table-wrap, .login-card {
  background: var(--panel);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  border-radius: 22px;
}
.panel { padding: 18px; margin-bottom: 18px; }
.filters { display: grid; grid-template-columns: repeat(3, minmax(180px, 1fr)) auto auto; gap: 12px; align-items: end; }
label { display: grid; gap: 7px; font-weight: 650; font-size: 14px; }
input, select, textarea {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px 13px;
  font: inherit;
  background: #fff;
  color: var(--text);
}
input:focus, select:focus, textarea:focus {
  outline: 3px solid rgba(31, 111, 235, 0.18);
  border-color: var(--primary);
}

.button {
  border: 0;
  border-radius: 12px;
  padding: 11px 14px;
  font: inherit;
  font-weight: 750;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: #edf2fb;
  color: var(--text);
  min-height: 42px;
}
.button:hover { text-decoration: none; filter: brightness(0.98); }
.button.primary { background: var(--primary); color: #fff; }
.button.primary:hover { background: var(--primary-dark); }
.button.ghost { background: #e8f1ff; color: var(--primary); }
.button.subtle { background: #f1f4f9; color: #3a465a; }
.button.danger { background: #fff0f0; color: var(--danger); }
.button.small { min-height: 34px; padding: 7px 9px; font-size: 13px; }
.button.full { width: 100%; }
.inline-form { display: inline; }

.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; min-width: 900px; }
th, td { padding: 14px 16px; border-bottom: 1px solid var(--border); text-align: left; vertical-align: top; }
th { color: var(--muted); font-size: 13px; text-transform: uppercase; letter-spacing: 0.05em; background: #fbfcff; }
tr:last-child td { border-bottom: 0; }
.badge { display: inline-flex; padding: 5px 9px; background: #eef5ff; border-radius: 999px; color: #225ca8; font-weight: 700; font-size: 13px; }
.actions { display: flex; gap: 8px; align-items: center; }
.empty { text-align: center; color: var(--muted); padding: 30px; }

.login-page {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
  background: radial-gradient(circle at top, #dbeafe, transparent 36%), var(--bg);
}
.login-card { width: min(420px, 100%); padding: 28px; }
.login-card h1 { font-size: 34px; }
.login-card form { display: grid; gap: 16px; margin-top: 24px; }
.alert {
  margin-top: 16px;
  padding: 12px 14px;
  border-radius: 12px;
  background: #fff0f0;
  color: var(--danger);
  font-weight: 650;
}
.form-panel { max-width: 860px; }
.classroom-form { display: grid; gap: 16px; margin-top: 18px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, minmax(220px, 1fr)); gap: 16px; }
.form-actions { display: flex; gap: 10px; align-items: center; }

@media (max-width: 820px) {
  .hero { align-items: stretch; flex-direction: column; }
  .stats { width: 100%; }
  .stats div { flex: 1; }
  .filters { grid-template-columns: 1fr; }
  .grid-2 { grid-template-columns: 1fr; }
  .topbar { align-items: flex-start; flex-direction: column; }
}

.filters-wide { grid-template-columns: repeat(3, minmax(180px, 1fr)) repeat(3, auto); }
.notice {
  margin-top: 16px;
  padding: 12px 14px;
  border-radius: 12px;
  font-weight: 650;
}
.notice.success { background: #ecfdf3; color: #116329; }
.notice.error { background: #fff0f0; color: var(--danger); }
.notice ul { margin: 8px 0 0 18px; padding: 0; font-weight: 500; }
.code-sample {
  margin-top: 14px;
  padding: 14px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: #fbfcff;
  overflow-x: auto;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 13px;
  line-height: 1.7;
}
.checkbox-label {
  display: flex;
  align-items: center;
  gap: 10px;
}
.checkbox-label input { width: auto; }
.muted-badge { margin-left: 8px; background: #f1f4f9; color: var(--muted); }

@media (max-width: 980px) {
  .filters-wide { grid-template-columns: 1fr; }
}

.wide-form { max-width: 1120px; }
.nested-panel {
  box-shadow: none;
  margin: 0;
  background: #fbfcff;
}
.nested-panel h2 { margin: 0 0 14px; font-size: 20px; }
.checkbox-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(260px, 1fr));
  gap: 10px 16px;
}
.checkbox-grid .checkbox-label {
  align-items: flex-start;
  font-weight: 600;
  line-height: 1.35;
}
.wide-table { min-width: 1500px; }
.text-cell {
  min-width: 280px;
  max-width: 460px;
  white-space: normal;
}
.badges-cell {
  min-width: 260px;
}
.badges-cell .badge {
  margin: 2px 3px 2px 0;
}

@media (max-width: 820px) {
  .checkbox-grid { grid-template-columns: 1fr; }
}


.clickable-row { cursor: pointer; }
.clickable-row:hover td { background: #f8fbff; }
.row-link { color: inherit; display: block; }
.row-link:hover { color: var(--primary); text-decoration: none; }
.room-link { color: var(--primary); }
.clamp {
  display: -webkit-box;
  -webkit-box-orient: vertical;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: normal;
  overflow-wrap: anywhere;
}
.clamp-2 { -webkit-line-clamp: 2; line-clamp: 2; }
.clamp-3 { -webkit-line-clamp: 3; line-clamp: 3; }
.detail-hero {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
}
.detail-hero h1 { margin-top: 8px; }
.back-link { font-weight: 750; color: var(--muted); }
.detail-actions { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.detail-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(300px, 0.75fr);
  gap: 18px;
}
.detail-card h2 { margin: 0 0 16px; font-size: 22px; }
.kv-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(180px, 1fr));
  gap: 12px;
  margin: 0;
}
.kv-grid div {
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 12px;
  background: #fbfcff;
}
.kv-grid dt {
  color: var(--muted);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 6px;
}
.kv-grid dd { margin: 0; font-weight: 700; overflow-wrap: anywhere; }
.detail-badges { display: flex; flex-wrap: wrap; gap: 8px; }
.long-text {
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  line-height: 1.65;
  padding: 14px;
  border-radius: 14px;
  background: #fbfcff;
  border: 1px solid var(--border);
}
.danger-zone { border-color: #ffd6d6; }

@media (max-width: 980px) {
  .detail-grid { grid-template-columns: 1fr; }
  .detail-hero { flex-direction: column; }
  .kv-grid { grid-template-columns: 1fr; }
}

.detail-edit-card h2 { margin: 0 0 16px; font-size: 22px; }
.detail-edit-card .nested-panel { margin-top: 2px; }
.sticky-actions {
  position: sticky;
  bottom: 12px;
  z-index: 5;
  padding: 12px;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(10px);
  box-shadow: 0 10px 35px rgba(23, 32, 51, 0.08);
}
.timestamp-cell {
  min-width: 150px;
  color: var(--muted);
  white-space: nowrap;
  font-size: 13px;
}