/* ===== Design tokens ===== */
:root {
  color-scheme: light;
  --bg: #f6f5f2;
  --surface: #ffffff;
  --surface-2: #f0efeb;
  --surface-3: #e7e5df;
  --border: #dedcd5;
  --text: #17171a;
  --text-2: #4d4c48;
  --text-3: #6f6d67;
  --accent: #2a64d6;
  --accent-ink: #ffffff;
  --accent-soft: #e4ecfb;
  --good: #16794a;
  --good-soft: #e1f3e8;
  --warn: #9a6200;
  --warn-soft: #fbf0d9;
  --bad: #c0362c;
  --bad-soft: #fbe5e2;
  --series-1: #2a78d6;
  --series-2: #eb6834;
  --series-muted: #b9b7b0;
  --code-bg: #f3f2ee;
  --shadow: 0 1px 2px rgba(20, 20, 20, .05), 0 2px 8px rgba(20, 20, 20, .04);
  --radius: 10px;
  --font: "Pretendard Variable", Pretendard, -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Malgun Gothic", "Noto Sans KR", system-ui, sans-serif;
  --mono: "JetBrains Mono", "D2Coding", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #131312;
    --surface: #1c1c1b;
    --surface-2: #252524;
    --surface-3: #2f2f2d;
    --border: #3a3a37;
    --text: #f1f0ec;
    --text-2: #c3c2b9;
    --text-3: #8f8d86;
    --accent: #5b8ff0;
    --accent-ink: #0d1424;
    --accent-soft: #1e2a44;
    --good: #4fc488;
    --good-soft: #17301f;
    --warn: #e0a83a;
    --warn-soft: #33280f;
    --bad: #f07a70;
    --bad-soft: #3a1c19;
    --series-1: #3987e5;
    --series-2: #d95926;
    --series-muted: #5c5b56;
    --code-bg: #20201f;
    --shadow: 0 1px 2px rgba(0, 0, 0, .3);
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #131312;
  --surface: #1c1c1b;
  --surface-2: #252524;
  --surface-3: #2f2f2d;
  --border: #3a3a37;
  --text: #f1f0ec;
  --text-2: #c3c2b9;
  --text-3: #8f8d86;
  --accent: #5b8ff0;
  --accent-ink: #0d1424;
  --accent-soft: #1e2a44;
  --good: #4fc488;
  --good-soft: #17301f;
  --warn: #e0a83a;
  --warn-soft: #33280f;
  --bad: #f07a70;
  --bad-soft: #3a1c19;
  --series-1: #3987e5;
  --series-2: #d95926;
  --series-muted: #5c5b56;
  --code-bg: #20201f;
  --shadow: 0 1px 2px rgba(0, 0, 0, .3);
}

/* ===== Base ===== */
* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; scroll-padding-top: calc(var(--header-h, 92px) + 12px); }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.6;
  overflow-x: hidden;
  /* 한글은 단어(어절) 단위로 줄바꿈, 너무 긴 토큰만 강제로 끊음 */
  word-break: keep-all;
  overflow-wrap: break-word;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3, h4 { line-height: 1.3; margin: 0 0 .5em; letter-spacing: -0.01em; }
h1 { font-size: 1.6rem; }
h2 { font-size: 1.3rem; }
h3 { font-size: 1.08rem; }
h4 { font-size: .98rem; }
p { margin: 0 0 .8em; }
code, pre, kbd { font-family: var(--mono); font-size: .88em; }
:not(pre) > code { background: var(--code-bg); border: 1px solid var(--border); padding: .05em .35em; border-radius: 5px; overflow-wrap: anywhere; }
/* 짧은 코드 조각(md()가 표시)은 한 줄로 유지 */
code.nw { white-space: nowrap; }
pre code, td code, th code { font-size: inherit; }
pre { background: var(--code-bg); border: 1px solid var(--border); border-radius: 8px; padding: 12px 14px; overflow-x: auto; line-height: 1.5; margin: 0 0 1em; }
kbd { border: 1px solid var(--border); border-bottom-width: 2px; border-radius: 4px; padding: 0 .35em; background: var(--surface); }
hr { border: 0; border-top: 1px solid var(--border); margin: 1.2em 0; }
table { border-collapse: collapse; }
ul, ol { padding-left: 1.3em; margin: 0 0 .8em; }
li { margin: .15em 0; }
blockquote { margin: 0 0 1em; padding: .4em 1em; border-left: 3px solid var(--accent); background: var(--accent-soft); border-radius: 0 8px 8px 0; color: var(--text-2); }
blockquote p:last-child { margin: 0; }

/* ===== Layout ===== */
.app-header {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.header-inner { max-width: 1280px; margin: 0 auto; padding: 10px 16px 0; }
.brand-row { display: flex; align-items: center; gap: 12px; justify-content: space-between; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 1.05rem; color: var(--text); }
.brand:hover { text-decoration: none; }
.brand-mark { width: 28px; height: 28px; border-radius: 8px; background: var(--accent); color: var(--accent-ink); display: grid; place-items: center; font-size: 13px; font-family: var(--mono); }
.brand small { color: var(--text-3); font-weight: 500; font-size: .8rem; }
.nav { display: flex; gap: 2px; overflow-x: auto; scrollbar-width: none; margin-top: 8px; }
.nav::-webkit-scrollbar { display: none; }
.nav.more-right { -webkit-mask-image: linear-gradient(to right, #000 calc(100% - 36px), transparent); mask-image: linear-gradient(to right, #000 calc(100% - 36px), transparent); }
.nav.more-left { -webkit-mask-image: linear-gradient(to left, #000 calc(100% - 36px), transparent); mask-image: linear-gradient(to left, #000 calc(100% - 36px), transparent); }
.nav.more-left.more-right { -webkit-mask-image: linear-gradient(to right, transparent, #000 36px, #000 calc(100% - 36px), transparent); mask-image: linear-gradient(to right, transparent, #000 36px, #000 calc(100% - 36px), transparent); }
.nav a {
  white-space: nowrap; padding: 8px 12px 10px; color: var(--text-2); font-weight: 500; font-size: .93rem;
  border-bottom: 2px solid transparent;
}
.nav a:hover { color: var(--text); text-decoration: none; }
.nav a.active { color: var(--accent); border-bottom-color: var(--accent); }
main { max-width: 1280px; margin: 0 auto; padding: 20px 16px 60px; }
.view { display: none; }
.view.active { display: block; }
.page-head { margin-bottom: 18px; }
.page-head p { color: var(--text-2); max-width: 820px; }
.grid { display: grid; gap: 16px; }
/* 넓은 화면에서도 최대 2열 (카드가 너무 좁아지지 않게) */
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(min(100%, max(300px, calc(50% - 8px))), 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
.kpi-row { display: grid; gap: 12px; grid-template-columns: repeat(3, minmax(0, 1fr)); }
@media (max-width: 480px) { .kpi-row { grid-template-columns: minmax(0, 1fr); } }
.split { display: grid; grid-template-columns: 300px minmax(0, 1fr); gap: 16px; align-items: start; }
@media (max-width: 900px) { .split { grid-template-columns: minmax(0, 1fr); } }
.sticky-side { position: sticky; top: calc(var(--header-h, 92px) + 12px); max-height: calc(100vh - var(--header-h, 92px) - 24px); overflow: auto; }
@media (max-width: 900px) {
  .sticky-side { position: static; max-height: none; }
  /* 좁은 화면: 플레이그라운드는 에디터를 먼저, 문제 목록은 높이를 제한해 문제가 바로 보이게 */
  .split.main-first > :last-child { order: -1; }
  .prob-aside { max-height: 340px; overflow: auto; }
}

/* ===== Components ===== */
.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 18px; box-shadow: var(--shadow); min-width: 0; }
.card.flat { box-shadow: none; }
.card h3 { margin-bottom: .4em; }
.muted { color: var(--text-3); }
.small { font-size: .85rem; }
.row { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.row.between { justify-content: space-between; }
.stack > * + * { margin-top: 12px; }
.spacer { flex: 1; }
.btn {
  display: inline-flex; align-items: center; gap: 6px; justify-content: center;
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
  padding: 7px 13px; border-radius: 8px; font: inherit; font-size: .9rem; font-weight: 500; cursor: pointer; line-height: 1.3;
}
.btn:hover { background: var(--surface-2); }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.btn.primary:hover { filter: brightness(1.08); }
.btn.ghost { background: transparent; border-color: transparent; }
.btn.ghost:hover { background: var(--surface-2); }
.btn.sm { padding: 4px 9px; font-size: .82rem; }
.chip {
  display: inline-flex; align-items: center; gap: 4px; border: 1px solid var(--border); background: var(--surface);
  color: var(--text-2); padding: 4px 10px; border-radius: 999px; font-size: .84rem; cursor: pointer; font: inherit; font-size: .84rem; white-space: nowrap;
}
.chip:hover { border-color: var(--text-3); }
.chip.on { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); font-weight: 600; }
.chip.on .count { color: inherit; opacity: .8; }
.chip .count { color: var(--text-3); font-weight: 400; font-size: .78rem; }
.badge { display: inline-block; padding: 1px 8px; border-radius: 999px; font-size: .75rem; font-weight: 600; background: var(--surface-2); color: var(--text-2); white-space: nowrap; }
.badge.lv-1 { background: var(--good-soft); color: var(--good); }
.badge.lv-2 { background: var(--warn-soft); color: var(--warn); }
.badge.lv-3 { background: var(--bad-soft); color: var(--bad); }
.badge.accent { background: var(--accent-soft); color: var(--accent); }
.badge.ok { background: var(--good-soft); color: var(--good); }
input[type=text], input[type=number], input[type=search], select, textarea {
  font: inherit; color: var(--text); background: var(--surface); border: 1px solid var(--border); border-radius: 8px; padding: 7px 10px; width: 100%; min-width: 0;
}
input:focus, select:focus, textarea:focus, .btn:focus-visible, .chip:focus-visible, .tabs button:focus-visible, .quiz-opt:focus-visible, summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }
textarea { resize: vertical; line-height: 1.55; }
label.field { display: block; font-size: .85rem; color: var(--text-2); font-weight: 500; }
label.field > input, label.field > select { margin-top: 4px; }
.field-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 12px; align-items: start; }
.callout { border: 1px solid var(--border); border-radius: 8px; padding: 10px 14px; background: var(--surface-2); font-size: .92rem; }
.callout.good { background: var(--good-soft); border-color: transparent; color: var(--text); }
.callout.bad { background: var(--bad-soft); border-color: transparent; color: var(--text); }
.callout.warn { background: var(--warn-soft); border-color: transparent; color: var(--text); }
.callout.info { background: var(--accent-soft); border-color: transparent; color: var(--text); }
.callout > :last-child { margin-bottom: 0; }
.tabs { display: flex; gap: 4px; border-bottom: 1px solid var(--border); margin-bottom: 14px; overflow-x: auto; scrollbar-width: none; }
/* 탭이 화면 밖에 더 있으면 가장자리를 흐리게 표시 */
.tabs.more-right { -webkit-mask-image: linear-gradient(to right, #000 calc(100% - 36px), transparent); mask-image: linear-gradient(to right, #000 calc(100% - 36px), transparent); }
.tabs.more-left { -webkit-mask-image: linear-gradient(to left, #000 calc(100% - 36px), transparent); mask-image: linear-gradient(to left, #000 calc(100% - 36px), transparent); }
.tabs.more-left.more-right { -webkit-mask-image: linear-gradient(to right, transparent, #000 36px, #000 calc(100% - 36px), transparent); mask-image: linear-gradient(to right, transparent, #000 36px, #000 calc(100% - 36px), transparent); }
.tabs button { background: none; border: 0; border-bottom: 2px solid transparent; padding: 8px 12px; font: inherit; color: var(--text-2); cursor: pointer; white-space: nowrap; font-weight: 500; }
.tabs button.on { color: var(--accent); border-bottom-color: var(--accent); }
.kpi { display: flex; flex-direction: column; gap: 2px; }
.kpi .v { font-size: 1.5rem; font-weight: 700; font-variant-numeric: tabular-nums; }
.kpi .l { font-size: .82rem; color: var(--text-3); }
.empty { padding: 30px; text-align: center; color: var(--text-3); }
.toast { position: fixed; bottom: 20px; left: 50%; transform: translateX(-50%); background: var(--text); color: var(--bg); padding: 9px 16px; border-radius: 8px; font-size: .9rem; z-index: 100; box-shadow: var(--shadow); max-width: calc(100vw - 32px); }
.md > :last-child { margin-bottom: 0; }
.md table, table.data { width: 100%; font-size: .88rem; margin-bottom: 1em; }
.md th, .md td, table.data th, table.data td { border-bottom: 1px solid var(--border); padding: 6px 10px; text-align: left; vertical-align: top; }
.md th, table.data th { background: var(--surface-2); font-weight: 600; }
table.data th { white-space: nowrap; }
.md td:first-child { min-width: 6.5em; }
.md td, table.data td { min-width: 4.5em; }
td .badge { white-space: normal; }
.nowrap { white-space: nowrap; }
.table-wrap { overflow: auto; max-width: 100%; border: 1px solid var(--border); border-radius: 8px; }
.table-wrap table { margin: 0; }
.md .table-wrap { margin-bottom: 1em; }

/* ===== Databricks 문법 대응표 ===== */
.syntax-wrap { overflow: visible; }
.syntax-table { table-layout: fixed; }
.syntax-table col.c-task { width: 8.5em; }
.syntax-table col.c-duck { width: 17%; }
.syntax-table col.c-spark { width: 27%; }
.syntax-table thead th { position: sticky; top: var(--header-h, 92px); z-index: 2; }
.syntax-table tbody th { background: none; font-weight: 600; white-space: normal; word-break: keep-all; }
.syntax-table code.snippet { display: block; background: none; border: 0; padding: 0; white-space: pre-wrap; overflow-wrap: anywhere; word-break: keep-all; line-height: 1.5; }
@media (max-width: 900px) {
  .syntax-table, .syntax-table tbody, .syntax-table tr, .syntax-table td, .syntax-table tbody th { display: block; width: auto; }
  .syntax-table colgroup, .syntax-table thead { display: none; }
  .syntax-table tr { border-bottom: 1px solid var(--border); padding: 8px 0; }
  .syntax-table tbody th { padding: 4px 12px; font-size: .95rem; border: 0; }
  .syntax-table td { border: 0; padding: 4px 12px; min-width: 0; }
  .syntax-table td::before { content: attr(data-label); display: block; font-size: .72rem; font-weight: 600; color: var(--text-3); }
  .syntax-table td[colspan]::before { content: none; }
}

/* ===== Result grid ===== */
.result-grid { overflow: auto; max-height: 420px; border: 1px solid var(--border); border-radius: 8px; background: var(--surface); }
.result-grid table { border-collapse: separate; border-spacing: 0; font-size: .84rem; width: max-content; min-width: 100%; }
.result-grid th { position: sticky; top: 0; background: var(--surface-2); text-align: left; font-weight: 600; padding: 6px 10px; border-bottom: 1px solid var(--border); white-space: nowrap; z-index: 1; }
.result-grid th small { display: block; font-weight: 400; color: var(--text-3); font-family: var(--mono); font-size: .72rem; }
.result-grid td { padding: 5px 10px; border-bottom: 1px solid var(--surface-3); white-space: nowrap; font-family: var(--mono); font-size: .8rem; max-width: 360px; overflow: hidden; text-overflow: ellipsis; }
.result-grid td.num { text-align: right; font-variant-numeric: tabular-nums; }
.result-grid td.null { color: var(--text-3); font-style: italic; }
.result-grid td.idx { color: var(--text-3); background: var(--surface-2); }
.result-meta { font-size: .8rem; color: var(--text-3); margin: 6px 2px; }
.result-grid th.num { text-align: right; }
@media (max-width: 600px) { .result-meta.row { padding-right: 52px; } }
.output-text { white-space: pre-wrap; font-family: var(--mono); font-size: .82rem; background: var(--code-bg); border: 1px solid var(--border); border-radius: 8px; padding: 10px 12px; margin: 0 0 8px; max-height: 320px; overflow: auto; }
.output-text.err { color: var(--bad); background: var(--bad-soft); border-color: transparent; }

/* ===== Editor ===== */
.editor { border: 1px solid var(--border); border-radius: 8px; overflow: hidden; background: var(--surface); }
.editor textarea.plain { border: 0; border-radius: 0; font-family: var(--mono); font-size: .88rem; min-height: 180px; padding: 10px 12px; background: var(--surface); tab-size: 4; white-space: pre; }
.editor .CodeMirror { height: auto; min-height: 180px; font-family: var(--mono); font-size: 13.5px; background: var(--surface); color: var(--text); line-height: 1.55; }
.editor .CodeMirror-scroll { min-height: 180px; max-height: 460px; }
.editor .CodeMirror-gutters { background: var(--surface-2); border-right: 1px solid var(--border); }
.editor .CodeMirror-linenumber { color: var(--text-3); }
.editor .CodeMirror-cursor { border-left-color: var(--text); }
.editor .CodeMirror-selected { background: var(--accent-soft) !important; }
/* CodeMirror 기본 테마(.cm-s-default, 나중에 로드됨)보다 우선하도록 .editor .cm-s-default 로 지정 */
.editor .cm-s-default .cm-keyword { color: #a43b9b; font-weight: 600; }
.editor .cm-s-default .cm-builtin, .editor .cm-s-default .cm-def, .editor .cm-s-default .cm-type { color: #2a64d6; }
.editor .cm-s-default .cm-string, .editor .cm-s-default .cm-string-2 { color: #1e7a3b; }
.editor .cm-s-default .cm-number, .editor .cm-s-default .cm-atom { color: #b45309; }
.editor .cm-s-default .cm-comment { color: var(--text-3); font-style: italic; }
.editor .cm-s-default .cm-operator, .editor .cm-s-default .cm-bracket, .editor .cm-s-default .cm-punctuation { color: var(--text-2); }
.editor .cm-s-default .cm-variable, .editor .cm-s-default .cm-property { color: var(--text); }
.editor .cm-s-default .cm-variable-2, .editor .cm-s-default .cm-variable-3 { color: #0e7490; }
:root[data-theme="dark"] .editor .cm-s-default .cm-keyword { color: #e08ad6; }
:root[data-theme="dark"] .editor .cm-s-default .cm-builtin, :root[data-theme="dark"] .editor .cm-s-default .cm-def, :root[data-theme="dark"] .editor .cm-s-default .cm-type { color: #7fa8f5; }
:root[data-theme="dark"] .editor .cm-s-default .cm-string, :root[data-theme="dark"] .editor .cm-s-default .cm-string-2 { color: #7fd09a; }
:root[data-theme="dark"] .editor .cm-s-default .cm-number, :root[data-theme="dark"] .editor .cm-s-default .cm-atom { color: #f0b46a; }
:root[data-theme="dark"] .editor .cm-s-default .cm-variable-2, :root[data-theme="dark"] .editor .cm-s-default .cm-variable-3 { color: #5fc8dc; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .editor .cm-s-default .cm-keyword { color: #e08ad6; }
  :root:not([data-theme="light"]) .editor .cm-s-default .cm-builtin, :root:not([data-theme="light"]) .editor .cm-s-default .cm-def, :root:not([data-theme="light"]) .editor .cm-s-default .cm-type { color: #7fa8f5; }
  :root:not([data-theme="light"]) .editor .cm-s-default .cm-string, :root:not([data-theme="light"]) .editor .cm-s-default .cm-string-2 { color: #7fd09a; }
  :root:not([data-theme="light"]) .editor .cm-s-default .cm-number, :root:not([data-theme="light"]) .editor .cm-s-default .cm-atom { color: #f0b46a; }
  :root:not([data-theme="light"]) .editor .cm-s-default .cm-variable-2, :root:not([data-theme="light"]) .editor .cm-s-default .cm-variable-3 { color: #5fc8dc; }
}
.editor .CodeMirror-matchingbracket { color: var(--accent) !important; background: var(--accent-soft); }
.editor-bar { display: flex; gap: 8px; align-items: center; padding: 8px 10px; background: var(--surface-2); border-top: 1px solid var(--border); flex-wrap: wrap; }

/* ===== Engine status ===== */
.status-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--text-3); display: inline-block; flex: none; }
.status-dot.ready { background: var(--good); }
.status-dot.loading { background: var(--warn); animation: pulse 1s infinite; }
.status-dot.error { background: var(--bad); }
@keyframes pulse { 50% { opacity: .35; } }
.engine-status { display: inline-flex; align-items: center; gap: 6px; font-size: .82rem; color: var(--text-2); }

/* ===== Schema browser ===== */
.schema-table { border-bottom: 1px solid var(--surface-3); }
.schema-table summary { cursor: pointer; padding: 6px 4px; display: flex; gap: 6px; align-items: center; font-family: var(--mono); font-size: .86rem; font-weight: 600; list-style: none; }
.schema-table summary::-webkit-details-marker { display: none; }
.schema-table summary::before { content: "▸"; color: var(--text-3); font-size: .75rem; transition: transform .15s; }
.schema-table[open] summary::before { transform: rotate(90deg); }
.schema-table summary .muted { font-weight: 400; margin-left: auto; font-size: .76rem; }
.schema-cols { padding: 0 4px 8px 18px; font-family: var(--mono); font-size: .78rem; }
.schema-cols div { display: flex; justify-content: space-between; gap: 8px; padding: 1px 0; cursor: pointer; }
.schema-cols div:hover { color: var(--accent); }
.schema-cols span:last-child { color: var(--text-3); }

/* ===== Q&A ===== */
.qa-list > * + * { margin-top: 10px; }
.qa { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
.qa-head { display: flex; gap: 10px; align-items: flex-start; padding: 13px 16px; cursor: pointer; }
.qa-head:hover { background: var(--surface-2); }
.qa-head:focus-visible { outline: 2px solid var(--accent); outline-offset: -2px; border-radius: var(--radius); }
.qa-q { flex: 1; font-weight: 600; }
.qa-meta { display: flex; gap: 6px; margin-top: 4px; flex-wrap: wrap; }
.qa-body { padding: 4px 18px 16px; border-top: 1px solid var(--border); }
.qa-section { margin-top: 14px; }
.qa-section > h4 { font-size: .8rem; text-transform: uppercase; letter-spacing: .04em; color: var(--text-3); margin-bottom: 6px; }
.icon-btn { background: none; border: 0; cursor: pointer; color: var(--text-3); font-size: 1.1rem; padding: 6px 8px; margin: -6px -4px; line-height: 1; min-width: 32px; min-height: 32px; border-radius: 6px; }
.icon-btn:focus-visible { outline: 2px solid var(--accent); }
.icon-btn.on { color: #a87400; }
:root[data-theme="dark"] .icon-btn.on { color: #f0b429; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .icon-btn.on { color: #f0b429; } }
.keypoints { list-style: none; padding: 0; }
.keypoints li { padding-left: 1.4em; position: relative; }
.keypoints li::before { content: "✓"; position: absolute; left: 0; color: var(--good); font-weight: 700; }
.check-list label { display: flex; gap: 8px; align-items: flex-start; padding: 4px 0; cursor: pointer; }
.check-list input { margin-top: 5px; }

/* ===== Problems ===== */
.prob-item { display: block; width: 100%; text-align: left; border: 0; background: none; padding: 8px 10px; border-radius: 8px; cursor: pointer; font: inherit; color: var(--text); }
.prob-item:hover { background: var(--surface-2); }
.prob-item.on { background: var(--accent-soft); }
.prob-item .t { font-size: .9rem; font-weight: 500; display: flex; gap: 6px; align-items: center; }
.prob-item .s { font-size: .75rem; color: var(--text-3); }
.solved-mark { color: var(--good); font-weight: 700; }

/* ===== Mock interview ===== */
.timer { font-family: var(--mono); font-size: 1.6rem; font-weight: 700; font-variant-numeric: tabular-nums; }
.timer.warn { color: var(--bad); }
.progress { height: 6px; background: var(--surface-3); border-radius: 999px; overflow: hidden; box-shadow: inset 0 0 0 1px var(--border); }
.progress > div { height: 100%; background: var(--accent); transition: width .3s; }
.rating { display: flex; gap: 6px; flex-wrap: wrap; }
.rating button { min-width: 44px; }
.bar-row { display: grid; grid-template-columns: 120px 1fr 48px; gap: 10px; align-items: center; font-size: .86rem; margin: 6px 0; }
.bar-row > span:first-child { word-break: keep-all; }
/* 좁은 화면: 라벨을 막대 위 한 줄로 */
@media (max-width: 560px) {
  .bar-row { grid-template-columns: minmax(0, 1fr) 48px !important; row-gap: 2px; }
  .bar-row > span:first-child { grid-column: 1 / -1; }
}
.bar-track { height: 10px; background: var(--surface-3); border-radius: 999px; overflow: hidden; box-shadow: inset 0 0 0 1px var(--border); }
.bar-fill { height: 100%; background: var(--series-1); border-radius: 999px; }

/* ===== Steps (cases) ===== */
.step { border: 1px solid var(--border); border-radius: var(--radius); background: var(--surface); margin-bottom: 12px; }
.step-head { display: flex; gap: 10px; align-items: center; padding: 12px 16px; }
.step-num { width: 26px; height: 26px; border-radius: 50%; background: var(--accent-soft); color: var(--accent); display: grid; place-items: center; font-weight: 700; font-size: .85rem; flex: none; }
.step-body { padding: 0 16px 14px; }
.model-answer { margin-top: 10px; border-left: 3px solid var(--good); background: var(--good-soft); padding: 10px 14px; border-radius: 0 8px 8px 0; }

/* ===== Charts ===== */
.chart { width: 100%; height: auto; display: block; }
.chart text { fill: var(--text-2); font-size: 11px; font-family: var(--font); }
.chart .axis line, .chart .axis path { stroke: var(--border); }
.chart .grid line { stroke: var(--surface-3); }
.chart text.halo { paint-order: stroke; stroke: var(--surface); stroke-width: 4px; stroke-linejoin: round; font-weight: 600; }
.chart-box { width: 100%; min-height: 200px; }
.chart-tip { position: fixed; pointer-events: none; background: var(--text); color: var(--bg); font-size: .78rem; padding: 6px 9px; border-radius: 6px; z-index: 50; white-space: nowrap; }
.legend { display: flex; gap: 14px; font-size: .8rem; color: var(--text-2); flex-wrap: wrap; }
.legend span::before { content: ""; display: inline-block; width: 10px; height: 10px; border-radius: 3px; background: var(--c); margin-right: 5px; vertical-align: -1px; }

/* ===== Quiz ===== */
.quiz-opt { display: block; width: 100%; text-align: left; border: 1px solid var(--border); background: var(--surface); border-radius: 8px; padding: 9px 12px; margin: 6px 0; font: inherit; cursor: pointer; color: var(--text); }
.quiz-opt:hover { border-color: var(--text-3); }
.quiz-opt.correct { border-color: var(--good); background: var(--good-soft); }
.quiz-opt.wrong { border-color: var(--bad); background: var(--bad-soft); }

/* ===== Home ===== */
.hero { display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr); gap: 16px; margin-bottom: 16px; }
@media (max-width: 860px) { .hero { grid-template-columns: minmax(0, 1fr); } }
.skill-row { display: grid; grid-template-columns: minmax(90px, 130px) minmax(0, 1fr); gap: 12px; padding: 10px 0; border-bottom: 1px solid var(--surface-3); }
.skill-row:last-child { border-bottom: 0; }
@media (max-width: 560px) { .skill-row { grid-template-columns: 1fr; gap: 2px; } }
.skill-row b { font-size: .92rem; }
.nav-card { display: block; color: var(--text); transition: border-color .15s; }
.nav-card:hover { border-color: var(--accent); text-decoration: none; }
.nav-card .k { font-size: .78rem; color: var(--accent); font-weight: 600; }
.theme-toggle { font-size: .85rem; }
@media (max-width: 560px) {
  .brand small { display: none; }
  .header-inner { padding-top: 8px; }
  h1 { font-size: 1.35rem; }
}

/* ===== depth-1 접이식 Q&A (흔한 실수, 꼬리 질문) ===== */
.mini-qa { display: flex; flex-direction: column; gap: 6px; }
.mini-item { border: 1px solid var(--border); border-radius: 8px; background: var(--surface); }
.mini-item summary { list-style: none; cursor: pointer; display: flex; gap: 8px; align-items: flex-start; padding: 8px 12px; font-size: .92rem; }
.mini-item summary::-webkit-details-marker { display: none; }
.mini-item summary::after { content: "▾"; margin-left: auto; color: var(--text-3); padding-left: 8px; }
.mini-item[open] summary::after { content: "▴"; }
.mini-item summary:hover { background: var(--surface-2); border-radius: 8px; }
.mini-mark { flex: none; width: 20px; height: 20px; border-radius: 50%; display: grid; place-items: center; font-size: .72rem; font-weight: 700; background: var(--surface-3); color: var(--text-2); margin-top: 1px; }
.mini-answer { padding: 2px 12px 10px 40px; font-size: .9rem; color: var(--text-2); }

/* ===== 결과 표 정렬 ===== */
.result-grid th.sortable { cursor: pointer; user-select: none; }
.result-grid th.sortable:hover { color: var(--accent); }
.result-grid th[data-sort="asc"]::after { content: " ▲"; color: var(--accent); font-size: .7rem; }
.result-grid th[data-sort="desc"]::after { content: " ▼"; color: var(--accent); font-size: .7rem; }
.result-meta.row { margin-top: 4px; }

/* ===== 코드 블록 도구 ===== */
.code-wrap { position: relative; }
.code-wrap > pre { margin-bottom: 1em; }
.code-tools { position: absolute; top: 6px; right: 6px; display: flex; gap: 4px; opacity: 0; transition: opacity .15s; }
.code-wrap:hover .code-tools, .code-tools:focus-within { opacity: 1; }
/* 터치 기기: 버튼이 코드 첫 줄을 가리지 않도록 코드 블록 아래 막대로 */
@media (hover: none) {
  .code-tools { opacity: 1; position: static; justify-content: flex-end; margin: -10px 0 1em; }
  .code-wrap pre { margin-bottom: 14px; }
}
.code-tool { font: inherit; font-size: .75rem; padding: 3px 8px; border-radius: 6px; border: 1px solid var(--border); background: var(--surface); color: var(--text-2); cursor: pointer; }
.code-tool:hover { color: var(--accent); border-color: var(--accent); }

/* ===== 자동 완성 팝업 ===== */
body .CodeMirror-hints { color: var(--text); background: var(--surface); border: 1px solid var(--border); border-radius: 8px; box-shadow: 0 6px 24px rgba(0,0,0,.18); padding: 4px; font-family: var(--mono); font-size: 12.5px; max-height: 18em; z-index: 60; max-width: min(560px, 92vw); }
body .CodeMirror-hint.ac-item { display: flex; gap: 8px; align-items: center; padding: 3px 8px; border-radius: 5px; color: var(--text); white-space: nowrap; }
body li.CodeMirror-hint-active.ac-item { background: var(--accent-soft); color: var(--text); }
.ac-kind { flex: none; width: 18px; height: 18px; border-radius: 4px; display: grid; place-items: center; font-size: 10px; font-weight: 700; font-family: var(--font); background: var(--surface-3); color: var(--text-2); }
.ac-column .ac-kind { background: #dcebfb; color: #1c5cab; }
.ac-table .ac-kind, .ac-alias .ac-kind { background: #e3f4e6; color: #16794a; }
.ac-func .ac-kind, .ac-method .ac-kind { background: #f3e5f5; color: #8e3b9b; }
.ac-var .ac-kind, .ac-module .ac-kind { background: #fdf0d9; color: #9a6200; }
:root[data-theme="dark"] .ac-column .ac-kind { background: #1e2a44; color: #8fb4f2; }
:root[data-theme="dark"] .ac-table .ac-kind, :root[data-theme="dark"] .ac-alias .ac-kind { background: #17301f; color: #4fc488; }
:root[data-theme="dark"] .ac-func .ac-kind, :root[data-theme="dark"] .ac-method .ac-kind { background: #33213a; color: #e08ad6; }
:root[data-theme="dark"] .ac-var .ac-kind, :root[data-theme="dark"] .ac-module .ac-kind { background: #33280f; color: #e0a83a; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .ac-column .ac-kind { background: #1e2a44; color: #8fb4f2; }
  :root:not([data-theme="light"]) .ac-table .ac-kind, :root:not([data-theme="light"]) .ac-alias .ac-kind { background: #17301f; color: #4fc488; }
  :root:not([data-theme="light"]) .ac-func .ac-kind, :root:not([data-theme="light"]) .ac-method .ac-kind { background: #33213a; color: #e08ad6; }
  :root:not([data-theme="light"]) .ac-var .ac-kind, :root:not([data-theme="light"]) .ac-module .ac-kind { background: #33280f; color: #e0a83a; }
}
.ac-text { flex: none; }
.ac-detail { margin-left: auto; padding-left: 16px; color: var(--text-3); font-size: 11px; font-family: var(--font); overflow: hidden; text-overflow: ellipsis; }
.editor .CodeMirror-activeline-background { background: color-mix(in srgb, var(--accent-soft) 45%, transparent); }

/* ===== 단축키 모달, 맨 위로 ===== */
.modal-backdrop { position: fixed; inset: 0; background: rgba(0,0,0,.35); z-index: 90; display: grid; place-items: center; padding: 16px; }
.modal { width: min(640px, 100%); max-height: 85vh; overflow: auto; }
.to-top { position: fixed; right: 18px; bottom: 18px; width: 40px; height: 40px; border-radius: 50%; border: 1px solid var(--border); background: var(--surface); color: var(--text-2); box-shadow: var(--shadow); font-size: 1.1rem; cursor: pointer; opacity: 0; pointer-events: none; transition: opacity .2s; z-index: 40; }
.to-top.show { opacity: 1; pointer-events: auto; }
.to-top:hover { color: var(--accent); border-color: var(--accent); }
@media (max-width: 560px) { #help-toggle { display: none; } }

/* ===== 문제: 사용 테이블 ===== */
.tables-box { margin-top: 12px; border: 1px solid var(--border); border-radius: 8px; background: var(--surface-2); padding: 10px 12px; }
.tables-box-title { font-size: .82rem; font-weight: 700; color: var(--text-2); margin-bottom: 6px; }
.tables-box-row + .tables-box-row { margin-top: 8px; padding-top: 8px; border-top: 1px dashed var(--border); }
.tbl-name { font-family: var(--mono); font-weight: 700; font-size: .88rem; background: var(--good-soft); color: var(--good); border: 0; border-radius: 6px; padding: 2px 8px; cursor: pointer; }
.col-chips { display: flex; flex-wrap: wrap; gap: 4px; margin-top: 6px; }
.col-chip { font-family: var(--mono); font-size: .76rem; background: var(--surface); color: var(--text-2); border: 1px solid var(--border); border-radius: 5px; padding: 1px 7px; cursor: pointer; }
.col-chip:hover, .tbl-name:hover { border-color: var(--accent); color: var(--accent); }

/* ===== 기타 ===== */
.visually-hidden { position: absolute !important; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
label.btn:focus-within { outline: 2px solid var(--accent); outline-offset: 1px; }
.disclosure > summary { cursor: pointer; font-weight: 600; list-style: none; display: flex; gap: 6px; align-items: center; }
.disclosure > summary::-webkit-details-marker { display: none; }
.disclosure > summary::before { content: "▸"; color: var(--text-3); font-size: .75rem; transition: transform .15s; }
.disclosure[open] > summary::before { transform: rotate(90deg); }
#help-toggle kbd { font-size: .72rem; padding: 0 .3em; }
.grading-rules { margin-top: 8px; }
.grading-rules summary { cursor: pointer; }
.grading-rules ul { margin: 4px 0 0; }
.filter-more > summary { cursor: pointer; font-size: .88rem; font-weight: 600; color: var(--text-2); }
@media (min-width: 901px) { .filter-more > summary { display: none; } .filter-more > div { margin-top: 0 !important; } }

/* ===== 문법 레퍼런스 ===== */
.seg { display: inline-flex; border: 1px solid var(--border); border-radius: 10px; padding: 3px; background: var(--surface-2); gap: 2px; }
.seg button { font: inherit; font-weight: 600; border: 0; background: none; color: var(--text-2); padding: 6px 16px; border-radius: 7px; cursor: pointer; display: inline-flex; gap: 6px; align-items: center; }
.seg button.on { background: var(--surface); color: var(--accent); box-shadow: var(--shadow); }
.seg button:focus-visible { outline: 2px solid var(--accent); }
.seg .count { font-size: .75rem; font-weight: 500; color: var(--text-3); }
.ref-bar { margin-bottom: 14px; gap: 10px; }
.ref-bar > .row { flex-wrap: nowrap; flex: 1 1 260px; justify-content: flex-end; min-width: 0; }
.ref-bar > .row > span { white-space: nowrap; }
.ref-bar input[type=search] { width: 100%; max-width: 320px; min-width: 0; }
.ref-layout { grid-template-columns: 250px minmax(0, 1fr); }
.ref-toc { padding: 12px 10px; }
.ref-toc > summary { cursor: pointer; font-weight: 600; padding: 2px 6px; }
.toc-tier + .toc-tier { margin-top: 14px; padding-top: 12px; border-top: 1px solid var(--border); }
.toc-tier-name { font-size: .78rem; font-weight: 700; color: var(--accent); padding: 0 6px 4px; }
.toc-appendix .toc-tier-name { color: var(--text-2); }
.toc-group { margin-top: 6px; }
.toc-group-name { font-size: .72rem; font-weight: 600; color: var(--text-3); padding: 2px 6px; letter-spacing: .02em; }
.ref-toc-list a { display: block; padding: 3px 6px 3px 12px; font-size: .86rem; color: var(--text-2); border-left: 2px solid transparent; border-radius: 0 6px 6px 0; line-height: 1.4; }
.ref-toc-list a:hover { color: var(--text); background: var(--surface-2); text-decoration: none; }
.ref-toc-list a.on { color: var(--accent); border-left-color: var(--accent); background: var(--accent-soft); font-weight: 600; }
.ref-tier + .ref-tier { margin-top: 36px; }
.ref-tier-title { font-size: 1.35rem; padding-bottom: 8px; border-bottom: 2px solid var(--border); margin: 18px 0 4px; }
.ref-appendix .ref-tier-title { color: var(--text-2); }
.ref-group-title { font-size: .95rem; color: var(--accent); margin: 22px 0 10px; }
.ref-item { margin-bottom: 14px; }
.ref-item.flash { animation: ref-flash 1.4s ease-out; }
@keyframes ref-flash { from { box-shadow: 0 0 0 3px var(--accent); } to { box-shadow: var(--shadow); } }
.ref-item-head h4 { font-size: 1.1rem; margin: 0; }
.ref-link { color: var(--text-3); font-weight: 600; padding: 0 4px; opacity: 0; transition: opacity .15s; }
.ref-item:hover .ref-link, .ref-link:focus-visible { opacity: 1; }
@media (hover: none) { .ref-link { opacity: .6; } }
.ref-summary { color: var(--text-2); margin: 4px 0 10px; }
.ref-label { font-size: .75rem; font-weight: 700; color: var(--text-3); margin: 12px 0 4px; letter-spacing: .02em; }
.ref-example .row .ref-label { margin: 0; }
.ref-example { margin-top: 12px; }
.ref-example > .row { margin-bottom: 4px; }
.ref-example pre, .ref-syntax { margin-bottom: 6px; }
.ref-syntax { background: var(--surface-2); }
.ref-out:not(:empty) { margin: 4px 0 8px; }
.ref-tips, .ref-dbx { margin-top: 10px; }
.ref-tips ul, .ref-dbx ul { margin-bottom: 0; }
.ref-related { margin: 10px 0 0; color: var(--text-2); }
@media (max-width: 900px) {
  .ref-layout { grid-template-columns: minmax(0, 1fr); }
  .ref-layout .sticky-side { position: sticky; top: var(--header-h, 92px); z-index: 4; }
  .ref-toc[open] { max-height: 60vh; overflow: auto; }
}
@media (min-width: 901px) { .ref-toc > summary { display: none; } }

/* ===== 코드 블록 문법 강조 (highlight.js) — 에디터와 같은 팔레트 ===== */
.tok-kw { color: #a43b9b; font-weight: 600; }
.tok-fn { color: #2a64d6; }
.tok-str { color: #1e7a3b; }
.tok-num, .tok-const { color: #b45309; }
.tok-com { color: var(--text-3); font-style: italic; }
.tok-op { color: var(--text-2); }
.tok-id, .tok-attr { color: #0e7490; }
:root[data-theme="dark"] .tok-kw { color: #e08ad6; }
:root[data-theme="dark"] .tok-fn { color: #7fa8f5; }
:root[data-theme="dark"] .tok-str { color: #7fd09a; }
:root[data-theme="dark"] .tok-num, :root[data-theme="dark"] .tok-const { color: #f0b46a; }
:root[data-theme="dark"] .tok-id, :root[data-theme="dark"] .tok-attr { color: #5fc8dc; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .tok-kw { color: #e08ad6; }
  :root:not([data-theme="light"]) .tok-fn { color: #7fa8f5; }
  :root:not([data-theme="light"]) .tok-str { color: #7fd09a; }
  :root:not([data-theme="light"]) .tok-num, :root:not([data-theme="light"]) .tok-const { color: #f0b46a; }
  :root:not([data-theme="light"]) .tok-id, :root:not([data-theme="light"]) .tok-attr { color: #5fc8dc; }
}