:root {
  --bg: #f5f7fb;
  --surface: #ffffff;
  --surface-2: #f9fbff;
  --line: #e7ebf3;
  --text: #1b2430;
  --muted: #6b7280;
  --primary: #2f6fed;
  --primary-dark: #1f57c3;
  --success: #1f9d67;
  --warning: #d58a08;
  --danger: #d34f4f;
  --shadow: 0 10px 30px rgba(25, 42, 70, 0.08);
  --radius: 20px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; font-family: Inter, Arial, sans-serif; background: var(--bg); color: var(--text); }
a { text-decoration: none; color: inherit; }
button, input, select, textarea { font: inherit; }

.app-shell {
  min-height: 100vh;
  display: grid;
  grid-template-columns: 270px 1fr;
}

.sidebar {
  background: linear-gradient(180deg, #172033 0%, #101827 100%);
  color: #fff;
  padding: 26px 18px;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 8px;
}
.brand h1 { margin: 0; font-size: 22px; }
.brand p { margin: 4px 0 0; color: rgba(255,255,255,.72); font-size: 13px; }
.brand-badge img {
  width: 48px;
  height: 48px;
  border-radius: 14px;
}

.nav { display: flex; flex-direction: column; gap: 8px; }
.nav-link {
  padding: 13px 14px;
  border-radius: 14px;
  color: rgba(255,255,255,.86);
  transition: .2s ease;
}
.nav-link:hover, .nav-link.active {
  background: rgba(255,255,255,.12);
  color: #fff;
}
.sidebar-footer { margin-top: auto; color: rgba(255,255,255,.6); padding: 10px; }

.main-content { padding: 28px; }
.topbar { margin-bottom: 20px; }
.topbar-between {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}
.topbar h2 { margin: 0 0 6px; font-size: 30px; }
.muted { color: var(--muted); margin: 0; }

.notify-chip {
  border: 1px solid var(--line);
  background: var(--surface);
  border-radius: 999px;
  padding: 12px 16px;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  box-shadow: var(--shadow);
}
.notify-chip.active {
  border-color: rgba(211,79,79,.24);
  background: rgba(211,79,79,.08);
}
.notify-chip b {
  min-width: 24px;
  height: 24px;
  border-radius: 999px;
  background: var(--danger);
  color: #fff;
  display: inline-grid;
  place-items: center;
  font-size: 12px;
}

.flash-stack { display: grid; gap: 10px; margin-bottom: 18px; }
.flash { padding: 14px 16px; border-radius: 14px; font-weight: 600; }
.flash.success { background: rgba(31,157,103,.12); color: #0d6f46; }
.flash.error { background: rgba(211,79,79,.12); color: #9d2b2b; }

.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; margin-bottom: 20px; }
.stat-card {
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  border-radius: var(--radius);
  padding: 22px;
}
.stat-card span { display: block; color: var(--muted); margin-bottom: 10px; }
.stat-card strong { font-size: 30px; line-height: 1.1; }
.stat-card.danger strong { color: var(--danger); }

.content-grid { display: grid; gap: 20px; margin-bottom: 20px; }
.content-grid.two-col { grid-template-columns: 1fr 1fr; }
.content-grid.three-col { grid-template-columns: repeat(3, 1fr); }
.content-grid.form-layout { grid-template-columns: 390px 1fr; align-items: start; }
.groups-layout { grid-template-columns: 430px 1fr !important; }

.panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}
.compact-panel { overflow: visible; }
.panel-head {
  padding: 20px 22px;
  border-bottom: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.panel-head h3 { margin: 0; font-size: 19px; }
.panel-head-stack { gap: 12px; flex-wrap: wrap; }

.form-grid {
  padding: 22px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}
.field { display: flex; flex-direction: column; gap: 8px; }
.field.full { grid-column: 1 / -1; }
.field label { font-weight: 600; font-size: 14px; }
input, select, textarea {
  width: 100%;
  border: 1px solid var(--line);
  background: var(--surface-2);
  border-radius: 14px;
  padding: 13px 14px;
  outline: none;
}
input:focus, select:focus, textarea:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 4px rgba(47,111,237,.10);
}
textarea { resize: vertical; }
button:disabled { opacity: .55; cursor: not-allowed; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 0;
  cursor: pointer;
  border-radius: 14px;
  padding: 12px 16px;
  font-weight: 700;
  background: #edf2ff;
  color: #3555a8;
}
.btn.primary { background: var(--primary); color: #fff; }
.btn.primary:hover { background: var(--primary-dark); }
.btn.danger { background: rgba(211,79,79,.12); color: var(--danger); }
.btn.small { padding: 9px 12px; border-radius: 12px; font-size: 13px; }

.table-wrap { overflow: auto; }
table { width: 100%; border-collapse: collapse; }
thead th {
  text-align: left;
  padding: 14px 18px;
  color: var(--muted);
  font-size: 13px;
  background: #fafcff;
  border-bottom: 1px solid var(--line);
}
tbody td {
  padding: 16px 18px;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}
tbody tr:hover { background: #fcfdff; }
td strong { display: block; }
td small { display: block; color: var(--muted); margin-top: 5px; }

.badge {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  padding: 7px 11px;
  font-size: 12px;
  font-weight: 700;
  background: #edf2ff;
  color: #3555a8;
}
.badge.success { background: rgba(31,157,103,.12); color: #17714d; }
.badge.warning { background: rgba(213,138,8,.14); color: #9b6505; }
.badge.danger { background: rgba(211,79,79,.12); color: #aa2e2e; }

.mini-grid {
  padding: 22px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}
.mini-box {
  padding: 18px;
  border-radius: 16px;
  background: #f8fbff;
  border: 1px solid var(--line);
}
.mini-box span { display: block; color: var(--muted); margin-bottom: 8px; }
.mini-box b { font-size: 28px; }
.standalone { margin: 0; }

.list-stack { padding: 16px 18px 20px; display: grid; gap: 12px; }
.list-item {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  align-items: center;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fbfdff;
}
.list-item small { display: block; color: var(--muted); margin-top: 4px; }
.empty { padding: 22px; color: var(--muted); }
.actions-row, .group-actions { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }
.inline-start-form { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }
.inline-filter-form select, .attendance-filter-form select { min-width: 180px; background: var(--surface-2); }
.filter-grid { padding-bottom: 0; }
.text-danger { color: var(--danger); }

@media (max-width: 1180px) {
  .stats-grid { grid-template-columns: 1fr 1fr; }
  .content-grid.two-col, .content-grid.form-layout, .content-grid.three-col, .groups-layout { grid-template-columns: 1fr !important; }
}

@media (max-width: 860px) {
  .app-shell { grid-template-columns: 1fr; }
  .sidebar { border-radius: 0 0 24px 24px; }
  .main-content { padding: 18px; }
  .topbar-between { flex-direction: column; }
}

@media (max-width: 600px) {
  .stats-grid, .mini-grid, .form-grid { grid-template-columns: 1fr; }
  .topbar h2 { font-size: 24px; }
}

.topbar-actions { position: relative; }
.top-gap { margin-top: 16px; }
.notify-chip { cursor: default; }

.notify-link { text-decoration: none; }
.group-picker-grid {
  padding: 22px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 14px;
}
.padded-grid { padding-top: 22px; }
.group-picker-card {
  display: block;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: #fbfdff;
  transition: .18s ease;
}
.group-picker-card:hover {
  border-color: rgba(47,111,237,.30);
  transform: translateY(-1px);
}
.group-picker-card.active {
  border-color: var(--primary);
  background: rgba(47,111,237,.06);
}
.group-picker-card strong { display: block; margin-bottom: 6px; }
.group-picker-card small { display: block; color: var(--muted); margin-bottom: 10px; }
.group-picker-card span { color: #3555a8; font-weight: 700; font-size: 13px; }
.subsection-divider {
  height: 1px;
  background: var(--line);
  margin: 0 22px;
}

.teacher-mobile-body {
  background: linear-gradient(180deg, #eff4ff 0%, #f7f9fd 100%);
}
.teacher-mobile-shell {
  max-width: 760px;
  margin: 0 auto;
  padding: 18px 14px 28px;
}
.teacher-login-card,
.teacher-mobile-panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 24px;
  box-shadow: var(--shadow);
  padding: 18px;
  margin-bottom: 16px;
}
.teacher-login-card {
  max-width: 460px;
  margin: 10vh auto 0;
}
.teacher-login-head,
.teacher-mobile-top {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: flex-start;
  margin-bottom: 18px;
}
.teacher-login-head h1,
.teacher-mobile-top h1 {
  margin: 0 0 6px;
  font-size: 28px;
}
.teacher-login-head p,
.teacher-mobile-top p {
  margin: 0;
  color: var(--muted);
}
.teacher-login-form,
.teacher-attendance-form,
.teacher-date-form {
  display: grid;
  gap: 14px;
}
.teacher-main-btn {
  width: 100%;
  min-height: 52px;
  border-radius: 16px;
}
.teacher-summary-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin-bottom: 16px;
}
.teacher-summary-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 18px;
  box-shadow: var(--shadow);
}
.teacher-summary-card span { display:block; color: var(--muted); margin-bottom: 8px; }
.teacher-summary-card strong { font-size: 28px; }
.teacher-card-list {
  display: grid;
  gap: 12px;
}
.teacher-group-card,
.teacher-student-card {
  border: 1px solid var(--line);
  background: #fbfdff;
  border-radius: 18px;
  padding: 15px;
}
.teacher-group-card {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
}
.teacher-group-card-active {
  border-color: rgba(47,111,237,.28);
  background: rgba(47,111,237,.06);
}
.teacher-group-card strong,
.teacher-student-head strong { display:block; margin-bottom: 4px; }
.teacher-group-card small,
.teacher-student-head small,
.back-link { color: var(--muted); }
.teacher-group-meta {
  display: grid;
  gap: 8px;
  justify-items: start;
  font-size: 13px;
  font-weight: 700;
  color: #3555a8;
}
.teacher-group-meta.align-right { justify-items: end; }
.teacher-mobile-top.compact { margin-bottom: 12px; }
.back-link { display:inline-block; margin-bottom: 8px; }
.teacher-status-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-top: 12px;
}
.teacher-radio-card {
  position: relative;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #eef6ff;
  overflow: hidden;
}
.teacher-radio-card.absent { background: #fff5f5; }
.teacher-radio-card.late { background: #fff8eb; }
.teacher-radio-card input {
  position: absolute;
  inset: 0;
  opacity: 0;
  cursor: pointer;
}
.teacher-radio-card span {
  display: block;
  text-align: center;
  padding: 13px 10px;
  font-weight: 700;
}
.teacher-radio-card input:checked + span {
  background: var(--primary);
  color: #fff;
}
.teacher-radio-card.absent input:checked + span { background: var(--danger); }
.teacher-radio-card.late input:checked + span { background: var(--warning); }
.teacher-form-stack {
  display: grid;
  gap: 14px;
  margin-top: 16px;
}

@media (max-width: 640px) {
  .teacher-login-card { margin-top: 6vh; }
  .teacher-login-head h1,
  .teacher-mobile-top h1 { font-size: 24px; }
  .teacher-summary-grid,
  .teacher-status-grid { grid-template-columns: 1fr; }
  .teacher-group-card { flex-direction: column; align-items: flex-start; }
  .teacher-group-meta.align-right { justify-items: start; }
}


.group-picker-grid-single {
  grid-template-columns: minmax(280px, 420px);
}

.group-picker-grid-single .group-picker-card {
  min-height: auto;
}

.teacher-groups-row {
  grid-template-columns: 1fr;
}

.full-width-panel {
  width: 100%;
}


.group-info-card {
  margin: 0 22px 18px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: linear-gradient(180deg, #fbfdff 0%, #f6f9ff 100%);
  box-shadow: 0 12px 28px rgba(25, 42, 70, 0.06);
}

.group-info-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.group-info-item {
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: rgba(255,255,255,.88);
}

.group-info-item span {
  display: block;
  font-size: 12px;
  line-height: 1.2;
  color: var(--muted);
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: .04em;
}

.group-info-item strong {
  display: block;
  font-size: 16px;
  line-height: 1.35;
  color: var(--text);
}

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

@media (max-width: 640px) {
  .group-info-card {
    margin: 0 16px 16px;
    padding: 14px;
  }

  .group-info-grid {
    grid-template-columns: 1fr;
  }
}