:root { --fg: #1a1a1a; --muted: #666; --line: #ccc; --accent: #2b6cb0; --ok: #2f855a; --bad: #c53030; --bg: #fafafa; }
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; background: var(--bg); color: var(--fg); font-family: -apple-system, "Apple SD Gothic Neo", "Noto Sans KR", "Malgun Gothic", sans-serif; font-size: 16px; line-height: 1.5; }
header { display: flex; align-items: center; gap: 16px; padding: 10px 16px; border-bottom: 1px solid var(--line); background: #fff; }
header h1 { font-size: 18px; margin: 0; }
header nav a { margin-right: 12px; color: var(--accent); text-decoration: none; cursor: pointer; }
header nav a.active { font-weight: bold; text-decoration: underline; }
main { max-width: 760px; margin: 0 auto; padding: 16px; }
h2 { font-size: 20px; margin: 8px 0 12px; }
h3 { font-size: 16px; margin: 16px 0 8px; }
button { font: inherit; padding: 8px 14px; border: 1px solid var(--line); border-radius: 6px; background: #fff; cursor: pointer; }
button.primary { background: var(--accent); color: #fff; border-color: var(--accent); }
button:disabled { opacity: .5; cursor: default; }
.row { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin: 8px 0; }
.muted { color: var(--muted); font-size: 14px; }
.card { background: #fff; border: 1px solid var(--line); border-radius: 8px; padding: 14px 16px; margin: 12px 0; }
.matrix { display: grid; grid-template-columns: repeat(3, 1fr); gap: 4px; width: min(100%, 420px); margin: 8px auto; padding: 4px; background: #333; }
.matrix .cell { width: 100%; aspect-ratio: 1 / 1; background: #fff; display: block; }
.options { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; width: min(100%, 560px); margin: 12px auto; }
.options.six { grid-template-columns: repeat(3, 1fr); }
.opt { position: relative; padding: 4px; border: 2px solid var(--line); border-radius: 6px; background: #fff; cursor: pointer; }
.opt .cell { width: 100%; aspect-ratio: 1 / 1; display: block; }
.opt .num { position: absolute; top: 2px; left: 6px; font-size: 14px; color: var(--muted); }
.opt.selected { border-color: var(--accent); box-shadow: 0 0 0 2px rgba(43,108,176,.3); }
.opt.correct { border-color: var(--ok); background: #e9f9ef; }
.opt.wrong { border-color: var(--bad); background: #fdecec; }
.opt:disabled { cursor: default; }
.verdict { font-weight: bold; font-size: 18px; margin: 8px 0; }
.verdict.ok { color: var(--ok); }
.verdict.bad { color: var(--bad); }
.explain ol, .explain ul { margin: 4px 0 8px 20px; padding: 0; }
.timer { font-variant-numeric: tabular-nums; font-size: 20px; font-weight: bold; }
.timer.warn { color: var(--bad); }
table { border-collapse: collapse; width: 100%; font-size: 14px; }
th, td { border-bottom: 1px solid var(--line); padding: 6px 8px; text-align: left; }
td.num, th.num { text-align: right; }
.qgrid { display: grid; grid-template-columns: repeat(auto-fill, minmax(44px, 1fr)); gap: 6px; }
.qgrid button { padding: 6px 0; font-size: 14px; }
.qgrid button.answered { background: #eef3fb; }
.qgrid button.current { border-color: var(--accent); border-width: 2px; }
.qgrid button.ok { background: #e9f9ef; border-color: var(--ok); }
.qgrid button.bad { background: #fdecec; border-color: var(--bad); }
.qgrid button.skip { background: #f1f1f1; }
details { margin: 6px 0; }
summary { cursor: pointer; }
code { background: #eee; padding: 1px 5px; border-radius: 4px; font-size: 13px; word-break: break-all; }
.kbd { font-size: 13px; color: var(--muted); }