:root {
  --primary: #2563eb;
  --bg: #f8fafc;
  --card-bg: #ffffff;
  --text: #0f172a;
  --border: #e2e8f0;
}

body {
  font-family: system-ui, -apple-system, sans-serif;
  background-color: var(--bg);
  color: var(--text);
  margin: 0;
  padding: 0;
  line-height: 1.5;
}

header {
  background-color: var(--primary);
  color: white;
  padding: 1.25rem 1rem;
  text-align: center;
}

h1 {
  margin: 0;
  font-size: 1.5rem;
}

main {
  max-width: 800px;
  margin: 2rem auto;
  padding: 0 1rem;
}

.hidden {
  display: none !important;
}

/* Public view */
#course-picker > h2,
#course-title {
  text-align: center;
  margin: 0 0 1.5rem;
}

#courses-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
}

.course-card {
  min-height: 6rem;
  background: var(--card-bg);
  color: var(--primary);
  border: 1px solid var(--border);
  border-left: 0.4rem solid var(--primary);
  border-radius: 0.5rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
  font-size: 1.2rem;
  font-weight: 700;
  text-align: left;
}

.course-card:hover {
  background: #eff6ff;
}

.back-button {
  width: auto;
  margin-bottom: 1.25rem;
  padding: 0.5rem 0.8rem;
  background: transparent;
  color: var(--primary);
  border: 1px solid var(--primary);
}

.back-button:hover {
  background: #eff6ff;
}

#meta-info {
  margin-bottom: 1.5rem;
  text-align: center;
  color: #64748b;
}

#student-randomizer {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding: 1.25rem;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

#student-randomizer h3,
#student-randomizer p {
  margin: 0;
}

#student-randomizer h3 {
  color: var(--primary);
  font-size: 1.25rem;
}

#student-randomizer > div p {
  color: #64748b;
}

#pick-random-student {
  width: auto;
}

#random-student {
  grid-column: 1 / -1;
  min-height: 2.25rem;
  padding: 0.75rem;
  background: #f8fafc;
  border: 1px dashed var(--border);
  border-radius: 0.25rem;
  text-align: center;
}

#random-student.has-selection {
  color: var(--primary);
  font-size: 1.5rem;
  font-weight: 700;
}

@media (max-width: 480px) {
  #student-randomizer {
    grid-template-columns: 1fr;
  }

  #pick-random-student,
  #random-student {
    width: auto;
    grid-column: 1;
  }
}

#groups-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
}

.group-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  padding: 1.25rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.group-card h3 {
  margin-top: 0;
  color: var(--primary);
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.5rem;
  font-size: 1.25rem;
}

.group-card ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.group-card li {
  padding: 0.25rem 0;
}

.loading, .empty-state, .error-state {
  text-align: center;
  padding: 2rem;
  color: #64748b;
  width: 100%;
}

.error-state {
  color: #ef4444;
}

/* Admin view */
#admin-form {
  background: var(--card-bg);
  padding: 1.5rem;
  border-radius: 0.5rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.form-group {
  margin-bottom: 1rem;
}

label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
}

input[type="password"],
input[type="number"],
input[type="text"],
input[type="file"] {
  width: 100%;
  padding: 0.5rem;
  border: 1px solid var(--border);
  border-radius: 0.25rem;
  box-sizing: border-box;
}

button {
  background-color: var(--primary);
  color: white;
  border: none;
  padding: 0.75rem 1.5rem;
  border-radius: 0.25rem;
  cursor: pointer;
  font-size: 1rem;
  width: 100%;
}

button:hover {
  background-color: #1d4ed8;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.65;
}

#status-message {
  margin-top: 1rem;
  padding: 1rem;
  border-radius: 0.25rem;
}

.success {
  background-color: #dcfce7;
  color: #166534;
}

.error {
  background-color: #fee2e2;
  color: #991b1b;
}

.course-management {
  margin-top: 2rem;
  padding: 1.5rem;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.section-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
}

.section-heading h2,
.section-heading p,
.admin-course-card h3,
.admin-course-card p {
  margin: 0;
}

.section-heading p,
.admin-course-card p {
  color: #64748b;
}

.section-heading .secondary-button {
  width: auto;
  flex: 0 0 auto;
}

#admin-courses {
  display: grid;
  gap: 0.75rem;
}

.admin-course-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
}

.admin-course-card h3 {
  margin-bottom: 0.2rem;
}

.course-actions {
  display: flex;
  flex: 0 0 auto;
  gap: 0.5rem;
}

.course-actions button {
  width: auto;
  padding: 0.6rem 0.8rem;
}

.secondary-button {
  background: #e2e8f0;
  color: #1e293b;
}

.secondary-button:hover {
  background: #cbd5e1;
}

@media (max-width: 640px) {
  .section-heading,
  .admin-course-card,
  .course-actions {
    align-items: stretch;
    flex-direction: column;
  }

  .section-heading .secondary-button,
  .course-actions button {
    width: 100%;
  }
}

.danger-zone {
  margin-top: 2rem;
  padding: 1.5rem;
  background: #fff1f2;
  border: 3px solid #ef4444;
  border-radius: 0.5rem;
  color: #7f1d1d;
}

.danger-zone h2 {
  margin: 0 0 0.5rem;
  color: #b91c1c;
}

.danger-zone p {
  margin: 0 0 1rem;
}

.danger-button {
  background: #dc2626;
  font-weight: 700;
}

.danger-button:hover {
  background: #991b1b;
}