:root {
  color-scheme: light;
  --bg: #f4f7f6;
  --panel: #ffffff;
  --soft: #edf3f1;
  --ink: #1d2a2f;
  --muted: #607174;
  --line: #d6dfdc;
  --green: #246b55;
  --green-2: #1d5745;
  --blue: #285f9f;
  --red: #b64a3b;
  --gold: #a46b12;
  --radius: 8px;
  --shadow: 0 18px 45px rgba(28, 43, 48, 0.1);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-width: 320px;
  background: var(--bg);
  color: var(--ink);
  font-family: "Microsoft YaHei", "PingFang SC", "Segoe UI", Arial, sans-serif;
  line-height: 1.6;
}

button,
input,
textarea {
  font: inherit;
}

button {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  color: var(--ink);
  padding: 10px 14px;
  cursor: pointer;
}

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

.primary {
  background: var(--green);
  border-color: var(--green);
  color: #fff;
}

.success {
  background: #173f35;
  border-color: #173f35;
  color: #fff;
}

.shell {
  max-width: 1320px;
  margin: 0 auto;
  padding: 22px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 18px;
}

.eyebrow {
  margin: 0 0 4px;
  color: var(--green);
  font-weight: 700;
}

h1 {
  margin: 0;
  font-size: 28px;
}

h2 {
  margin: 0 0 12px;
  font-size: 18px;
}

.status-pill,
.paper-meta span,
.q-head span {
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--soft);
  padding: 4px 10px;
  color: var(--muted);
  font-size: 13px;
}

.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 340px;
  gap: 18px;
}

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

.workspace {
  padding: 18px;
}

.panel {
  padding: 16px;
}

.side {
  display: grid;
  gap: 14px;
  align-content: start;
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: end;
  gap: 10px;
  margin-bottom: 12px;
}

.learner {
  display: grid;
  gap: 4px;
  min-width: 220px;
  color: var(--muted);
  font-size: 14px;
}

input,
textarea {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 10px 12px;
  background: #fff;
  color: var(--ink);
}

textarea {
  min-height: 86px;
  resize: vertical;
  font-family: Consolas, "Courier New", monospace;
}

.paper-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}

.questions {
  display: grid;
  gap: 14px;
}

.question-card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
  background: #fff;
}

.q-head {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}

.q-body {
  white-space: pre-wrap;
  font-weight: 700;
  margin-bottom: 12px;
}

.options {
  display: grid;
  gap: 8px;
}

.option {
  display: grid;
  grid-template-columns: 26px 1fr;
  gap: 8px;
  align-items: start;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 9px 10px;
}

.program-block {
  display: grid;
  gap: 10px;
}

.io {
  background: #f8faf9;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 10px;
  white-space: pre-wrap;
}

.test-item {
  display: grid;
  gap: 8px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 10px;
}

.result-panel {
  border: 1px solid #c8d8d0;
  border-left: 5px solid var(--green);
  border-radius: var(--radius);
  background: #f7fbf9;
  padding: 14px;
  margin-bottom: 14px;
}

.score {
  font-size: 34px;
  font-weight: 800;
  color: var(--green-2);
}

.q-review {
  margin-top: 12px;
  border-top: 1px solid var(--line);
  padding-top: 12px;
}

.ok {
  color: var(--green);
  font-weight: 700;
}

.bad {
  color: var(--red);
  font-weight: 700;
}

.stack {
  display: grid;
  gap: 10px;
}

.mini-card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 10px;
  background: #fff;
}

.mini-card strong {
  display: block;
}

.empty {
  color: var(--muted);
}

.hidden {
  display: none;
}

code,
pre {
  font-family: Consolas, "Courier New", monospace;
}

pre {
  overflow-x: auto;
  background: #f8faf9;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 10px;
  white-space: pre-wrap;
}

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

  .side {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .shell {
    padding: 12px;
  }

  h1 {
    font-size: 22px;
  }

  .toolbar {
    align-items: stretch;
  }

  .toolbar button,
  .learner {
    width: 100%;
  }
}