:root {
  --bg: #fafafa;
  --fg: #1a1a1a;
  --muted: #6b7280;
  --accent: #2563eb;
  --border: #e5e7eb;
  --card: #ffffff;
  --error: #b91c1c;
  --ok: #047857;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; background: var(--bg); color: var(--fg); }
.topbar {
  display: flex; gap: 1.5rem; align-items: center;
  padding: 0.75rem 1.5rem; border-bottom: 1px solid var(--border);
  background: var(--card);
}
.brand { font-weight: 700; text-decoration: none; color: var(--fg); }
.topbar nav { display: flex; gap: 1rem; margin-left: auto; }
.topbar nav a { color: var(--muted); text-decoration: none; }
.topbar nav a:hover { color: var(--fg); }
.container { max-width: 880px; margin: 2rem auto; padding: 0 1.5rem; }
h1 { margin-top: 0; }
.card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: 8px; padding: 1.5rem; margin-bottom: 1.5rem;
}
.stack > * + * { margin-top: 1rem; }
.row { display: flex; gap: 0.75rem; align-items: center; }
.muted { color: var(--muted); }
.small { font-size: 0.875rem; }
.error { color: var(--error); }
.info { color: var(--ok); }
label { display: block; font-weight: 500; }
label > input, label > textarea, input, textarea, select {
  display: block; width: 100%; padding: 0.5rem 0.75rem; margin-top: 0.25rem;
  border: 1px solid var(--border); border-radius: 6px; font: inherit;
  background: #fff;
}
button, .btn {
  display: inline-block; padding: 0.5rem 1rem; border-radius: 6px;
  border: 1px solid var(--accent); background: var(--accent); color: #fff;
  font: inherit; cursor: pointer; text-decoration: none;
}
button.link, .link {
  background: transparent; color: var(--accent); border-color: transparent;
  padding: 0.5rem 0;
}
button:disabled { opacity: 0.6; cursor: not-allowed; }
.assignment-meta {
  display: flex; gap: 1rem; align-items: center; justify-content: flex-end;
  padding: 0.5rem 0; border-bottom: 1px dashed var(--border); margin-bottom: 1rem;
}
.save-indicator { font-size: 0.875rem; color: var(--muted); }
.save-indicator[data-state="saving"] { color: var(--muted); }
.save-indicator[data-state="saved"] { color: var(--ok); }
.save-indicator[data-state="error"] { color: var(--error); }
.comp { margin: 1rem 0; }
.comp-info {
  background: #eff6ff; border-left: 4px solid var(--accent);
  padding: 0.75rem 1rem; border-radius: 4px;
}
.comp-section { border-top: 2px solid var(--border); padding-top: 1rem; margin-top: 2rem; }
.comp-section > h2 { margin-top: 0; }
.comp-text .prompt, .comp-upload .prompt { display: block; margin-bottom: 0.25rem; font-weight: 500; }
.comp-check { list-style: none; padding: 0; }
.comp-check li { padding: 0.25rem 0; }
.comp-check label { display: flex; gap: 0.5rem; align-items: center; font-weight: 400; }
table { width: 100%; border-collapse: collapse; }
th, td { text-align: left; padding: 0.5rem 0.75rem; border-bottom: 1px solid var(--border); }
th { background: #f3f4f6; font-weight: 600; }
.code { font-family: ui-monospace, "Cascadia Mono", Menlo, monospace; }