:root {
  color-scheme: light;
  font-family: 'Inter', 'Segoe UI', system-ui, -apple-system, sans-serif;
  --background: #f6f7fb;
  --sidebar: #ffffffee;
  --card: #ffffff;
  --border: #e2e8f0;
  --text: #1f2933;
  --muted: #64748b;
  --primary: #3b82f6;
  --primary-soft: #eff6ff;
  --radius-lg: 22px;
  --radius-md: 16px;
  --shadow:
    0 16px 40px -24px rgba(15, 23, 42, 0.35),
    0 4px 10px -8px rgba(15, 23, 42, 0.25);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--background);
  color: var(--text);
}

#root {
  min-height: 100vh;
}

.shell {
  min-height: 100vh;
  display: grid;
  grid-template-columns: 280px 1fr;
  backdrop-filter: blur(12px);
}

.sidebar {
  display: flex;
  flex-direction: column;
  gap: 48px;
  padding: 48px 40px;
  background: var(--sidebar);
  border-right: 1px solid rgba(148, 163, 184, 0.25);
}

.brand {
  display: flex;
  align-items: center;
  gap: 18px;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  border-radius: 14px;
  background: linear-gradient(140deg, #3b82f6, #6366f1);
  color: white;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.brand-copy span {
  font-size: 20px;
  font-weight: 600;
}

.brand-copy small {
  color: var(--muted);
  font-weight: 400;
}

.menu {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.menu-link {
  text-decoration: none;
  padding: 12px 16px;
  border-radius: 14px;
  color: var(--muted);
  font-weight: 500;
  transition: all 0.2s ease-in-out;
}

.menu-link:hover {
  color: var(--text);
  background: rgba(148, 163, 184, 0.1);
}

.menu-link.is-active {
  background: var(--primary-soft);
  color: var(--primary);
  box-shadow: inset 0 0 0 1px rgba(59, 130, 246, 0.15);
}

.content {
  padding: 48px 56px;
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.screen {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.screen-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 24px;
}

.screen-header h1 {
  margin: 0;
  font-size: 30px;
  letter-spacing: -0.02em;
}

.screen-subtitle {
  margin: 8px 0 0;
  color: var(--muted);
}

.header-actions {
  display: flex;
  gap: 12px;
}

.screen-toolbar {
  display: flex;
  justify-content: flex-end;
}

.search {
  position: relative;
  display: inline-flex;
  flex-direction: column;
  gap: 6px;
}

.search-label {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--muted);
}

.search input {
  min-width: 280px;
  padding: 12px 16px;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: white;
  font-size: 15px;
  transition: border-color 0.2s ease;
}

.search input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.12);
}

.card-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 22px;
  border-radius: var(--radius-lg);
  background: var(--card);
  text-decoration: none;
  color: inherit;
  border: 1px solid rgba(226, 232, 240, 0.7);
  box-shadow: 0 20px 40px -30px rgba(15, 23, 42, 0.4);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 30px 60px -35px rgba(15, 23, 42, 0.45);
}

.card-title {
  font-weight: 600;
  font-size: 18px;
}

.card-meta {
  color: var(--muted);
  font-size: 14px;
}

.card-footer {
  font-size: 13px;
  color: var(--muted);
}

.empty {
  padding: 24px;
  border-radius: var(--radius-lg);
  background: rgba(148, 163, 184, 0.08);
  color: var(--muted);
  text-align: center;
}

.btn {
  appearance: none;
  border: 1px solid transparent;
  border-radius: 999px;
  padding: 10px 20px;
  font-size: 15px;
  font-weight: 500;
  cursor: pointer;
  background: white;
  color: var(--text);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: all 0.2s ease;
  box-shadow: inset 0 0 0 1px rgba(148, 163, 184, 0.35);
}

.btn:hover {
  box-shadow: inset 0 0 0 1px rgba(99, 102, 241, 0.45);
}

.btn.primary {
  background: linear-gradient(135deg, #3b82f6, #6366f1);
  color: white;
  box-shadow: 0 12px 20px -12px rgba(79, 70, 229, 0.6);
}

.btn.primary:hover {
  box-shadow: 0 16px 32px -16px rgba(79, 70, 229, 0.65);
}

.panel {
  border-radius: var(--radius-lg);
  background: var(--card);
  padding: 28px;
  border: 1px solid rgba(226, 232, 240, 0.8);
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.data-grid {
  margin: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 18px;
}

.data-grid dt {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.data-grid dd {
  margin: 4px 0 0;
  font-size: 17px;
  font-weight: 500;
}

.link {
  color: var(--primary);
  text-decoration: none;
}

.link:hover {
  text-decoration: underline;
}

.chips {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border-radius: 999px;
  background: rgba(99, 102, 241, 0.08);
  color: var(--primary);
  padding: 10px 18px;
  text-decoration: none;
  border: 1px solid rgba(99, 102, 241, 0.18);
  font-weight: 500;
}

.chip:hover {
  background: rgba(99, 102, 241, 0.14);
}

.schedule-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.schedule-list li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-radius: 14px;
  background: rgba(148, 163, 184, 0.08);
  padding: 12px 16px;
}

.schedule-day {
  font-weight: 600;
}

.schedule-hour {
  color: var(--muted);
  font-size: 14px;
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.form {
  gap: 24px;
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 18px;
}

.form label,
fieldset label {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 14px;
  color: var(--muted);
}

.form input,
.form select,
fieldset input,
fieldset select {
  border-radius: 14px;
  border: 1px solid var(--border);
  padding: 12px 14px;
  font-size: 15px;
  color: var(--text);
  background: white;
  transition: border-color 0.2s ease;
}

.form input:focus,
.form select:focus,
fieldset input:focus,
fieldset select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

.checkbox-group {
  border: 1px solid rgba(226, 232, 240, 0.8);
  border-radius: var(--radius-md);
  padding: 20px;
  background: rgba(15, 23, 42, 0.02);
}

.checkbox-group legend,
.schedule-fields legend {
  font-weight: 600;
  color: var(--text);
  margin-bottom: 12px;
}

.checkbox-rows {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px 16px;
  align-items: stretch;
}

.checkbox-item {
  flex-direction: row;
  align-items: center;
  justify-content: flex-start;
  gap: 12px;
  padding: 12px 16px;
  border-radius: 16px;
  border: 1px solid rgba(148, 163, 184, 0.4);
  background: rgba(255, 255, 255, 0.9);
  box-shadow: inset 0 0 0 1px rgba(15, 23, 42, 0.02);
  cursor: pointer;
  transition: border-color 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
  width: 100%;
}

.checkbox-item:hover {
  border-color: rgba(59, 130, 246, 0.45);
  box-shadow: inset 0 0 0 1px rgba(59, 130, 246, 0.15), 0 8px 18px -14px rgba(15, 23, 42, 0.4);
  background: rgba(248, 250, 255, 0.9);
}

.checkbox-item input {
  width: 18px;
  height: 18px;
  margin: 0;
}

.schedule-fields {
  border: 1px solid rgba(226, 232, 240, 0.8);
  border-radius: var(--radius-md);
  padding: 20px;
  background: rgba(15, 23, 42, 0.02);
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.schedule-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  align-items: end;
  gap: 12px;
}

.form-actions {
  display: flex;
  justify-content: flex-end;
  gap: 12px;
}

.add-student {
  flex-direction: row;
  align-items: flex-end;
  justify-content: space-between;
}

.add-student select {
  min-width: 240px;
}

@media (max-width: 960px) {
  .shell {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: sticky;
    top: 0;
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
    padding: 24px;
    border-right: none;
    border-bottom: 1px solid rgba(148, 163, 184, 0.2);
    gap: 24px;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(14px);
  }

  .menu {
    flex-direction: row;
    gap: 8px;
  }

  .content {
    padding: 32px 24px 56px;
  }

  .screen-header {
    flex-direction: column;
    align-items: stretch;
  }

  .screen-toolbar {
    justify-content: flex-start;
  }
}
