:root {
  color-scheme: light;
  --bg: #f5f7fb;
  --panel: #ffffff;
  --text: #172033;
  --muted: #667085;
  --line: #d9e0ea;
  --accent: #1b6fd8;
  --accent-dark: #1559ad;
  --shadow: 0 16px 40px rgba(22, 34, 51, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: Arial, Helvetica, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.app {
  width: min(1180px, calc(100% - 32px));
  margin: 32px auto;
  display: grid;
  grid-template-columns: 360px minmax(0, 1fr);
  gap: 20px;
}

.panel,
.viewer {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.panel {
  padding: 24px;
  align-self: start;
}

.title-block {
  margin-bottom: 24px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: 26px;
  line-height: 1.15;
}

.controls {
  display: grid;
  gap: 16px;
}

label {
  display: grid;
  gap: 8px;
  font-size: 14px;
  font-weight: 700;
}

select,
button {
  width: 100%;
  min-height: 44px;
  border-radius: 6px;
  font: inherit;
}

select {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--text);
  padding: 0 12px;
}

select:disabled {
  background: #eef2f7;
  color: #98a2b3;
}

button {
  margin-top: 4px;
  border: 0;
  background: var(--accent);
  color: white;
  font-weight: 700;
  cursor: pointer;
}

button:hover:not(:disabled) {
  background: var(--accent-dark);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
}

.hint {
  min-height: 40px;
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.45;
  overflow-wrap: anywhere;
}

.lookup {
  display: grid;
  gap: 14px;
  margin-top: 22px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.class-result {
  min-height: 76px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #f8fafc;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.45;
}

.class-list {
  display: grid;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  color: var(--text);
}

.class-list li {
  display: block;
}

.day {
  color: var(--accent);
  font-weight: 700;
}

.viewer {
  min-height: calc(100vh - 64px);
  overflow: hidden;
}

iframe {
  display: block;
  width: 100%;
  height: calc(100vh - 66px);
  border: 0;
}

@media (max-width: 850px) {
  .app {
    grid-template-columns: 1fr;
    margin: 16px auto;
  }

  .viewer {
    min-height: 70vh;
  }

  iframe {
    height: 70vh;
  }
}