:root {
  --bg: #f4f7fb;
  --panel: #ffffff;
  --primary: #2d6cdf;
  --primary-soft: #ebf1ff;
  --danger: #d64545;
  --success: #2d9d78;
  --muted: #5a6b85;
  --border: #dfe8f5;
  --text: #1d2a39;
  --shadow: 0 10px 25px rgba(18, 35, 54, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
}

button, input, select {
  font: inherit;
}

button {
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 10px;
  padding: 0.7rem 1rem;
  cursor: pointer;
}

button:hover {
  filter: brightness(0.98);
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.2rem 2rem;
  background: linear-gradient(135deg, #1a2f52, #2d6cdf);
  color: white;
}

.eyebrow {
  margin: 0 0 0.25rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-size: 0.7rem;
  opacity: 0.8;
}

h1, h2 {
  margin: 0;
}

.status {
  background: rgba(255, 255, 255, 0.14);
  padding: 0.45rem 0.8rem;
  border-radius: 999px;
  font-size: 0.9rem;
}

.layout {
  display: grid;
  grid-template-columns: 350px minmax(0, 1fr);
  gap: 1.5rem;
  padding: 1.5rem 2rem 2rem;
}

.sidebar,
.main-panel {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.card {
  background: var(--panel);
  border-radius: 18px;
  padding: 1.1rem;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}

form {
  display: grid;
  gap: 0.8rem;
}

label {
  display: grid;
  gap: 0.35rem;
  color: var(--muted);
  font-size: 0.9rem;
}

input, select {
  width: 100%;
  padding: 0.7rem 0.8rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #fff;
}

.plain-list,
.student-list {
  display: grid;
  gap: 0.6rem;
  margin-top: 1rem;
  padding-left: 0;
  list-style: none;
}

.plain-list li,
.student-list li {
  background: var(--primary-soft);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.7rem 0.8rem;
  line-height: 1.5;
}

.student-form {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1rem;
}

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

.day-column {
  background: #f9fbff;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 0.85rem;
  min-height: 240px;
}

.day-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.8rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--border);
}

.day-header strong {
  font-size: 1rem;
}

.override-badge {
  font-size: 0.7rem;
  background: #fff0d8;
  color: #8a5b00;
  padding: 0.2rem 0.45rem;
  border-radius: 999px;
}

.slot-list {
  display: grid;
  gap: 0.5rem;
}

.slot {
  background: white;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.55rem 0.6rem;
  display: grid;
  gap: 0.35rem;
}

.slot-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
}

.slot select {
  padding: 0.45rem 0.55rem;
  font-size: 0.9rem;
}

.slot .assigned {
  font-size: 0.82rem;
  color: var(--success);
  font-weight: 600;
}

.merged-slot {
  background: var(--primary-soft);
  border-left: 4px solid var(--primary);
}

.block-times,
.slot summary {
  font-size: 0.82rem;
  color: var(--muted);
}

.slot summary {
  cursor: pointer;
}

.block-editors {
  display: grid;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

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

  .student-form {
    grid-template-columns: 1fr;
  }
}