/* Layout concept: a database client. Navigator on the left, work in the middle, tables on the right. */
:root {
  --bg: #e9eef4;
  --surface: #f8fafc;
  --raised: #ffffff;
  --ink: #142032;
  --muted: #526176;
  --line: #c6d1de;
  --accent: #1a56b8;
  --accent-ink: #ffffff;
  --accent-soft: #d9e5f8;
  --mark: #b77900;
  --good: #0f7a56;
  --good-soft: #d6f0e6;
  --warn: #9a5b06;
  --warn-soft: #f8e8cd;
  --bad: #b92d36;
  --bad-soft: #f9dfe0;
  --string: #0f7a56;
  --number: #9a5b06;
  --font-display: "IBM Plex Sans Condensed", "Arial Narrow", Arial, sans-serif;
  --font-body: "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", Consolas, "Courier New", monospace;
  --gutter-l: max(16px, env(safe-area-inset-left, 0px));
  --gutter-r: max(16px, env(safe-area-inset-right, 0px));
  --head: 57px;
  color-scheme: light;
  padding-top: env(safe-area-inset-top, 0px);
  padding-bottom: env(safe-area-inset-bottom, 0px);
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0e1520; --surface: #151f2c; --raised: #1b2736; --ink: #e5ebf3; --muted: #9aa9bb; --line: #2c3a4c;
    --accent: #84b2ff; --accent-ink: #0c1420; --accent-soft: #20324d; --mark: #f0bd4f;
    --good: #55cca3; --good-soft: #143429; --warn: #e8b061; --warn-soft: #3a2b14; --bad: #f28b90; --bad-soft: #3d1d21;
    --string: #55cca3; --number: #e8b061; color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0e1520; --surface: #151f2c; --raised: #1b2736; --ink: #e5ebf3; --muted: #9aa9bb; --line: #2c3a4c;
  --accent: #84b2ff; --accent-ink: #0c1420; --accent-soft: #20324d; --mark: #f0bd4f;
  --good: #55cca3; --good-soft: #143429; --warn: #e8b061; --warn-soft: #3a2b14; --bad: #f28b90; --bad-soft: #3d1d21;
  --string: #55cca3; --number: #e8b061; color-scheme: dark;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 400 16px/1.6 var(--font-body); }
body::before { content: ""; position: fixed; inset: 0 0 auto; height: env(safe-area-inset-top, 0px); z-index: 30; background: var(--surface); }
h1, h2, h3 { font-family: var(--font-display); line-height: 1.15; text-wrap: balance; margin: 0; }
h2 { font-size: 2rem; font-weight: 700; }
h3 { font-size: 1.25rem; font-weight: 600; }
p { margin: 0; }
button, select { font: inherit; color: inherit; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
code { font: 500 0.88em var(--font-mono); background: var(--accent-soft); padding: 0.1em 0.32em; border-radius: 3px; overflow-wrap: anywhere; }

/* Header */
.top { position: sticky; top: env(safe-area-inset-top, 0px); z-index: 20; display: flex; flex-wrap: wrap; align-items: center; gap: 0 20px; background: var(--surface); border-bottom: 1px solid var(--line); padding-left: var(--gutter-l); padding-right: var(--gutter-r); min-height: var(--head); }
.brand { font: 700 1.3rem var(--font-display); white-space: nowrap; }
.brand-kw { font: 500 1.02rem var(--font-mono); color: var(--accent); }
.tabs { display: flex; gap: 2px; overflow-x: auto; flex: 1 1 auto; min-width: 0; scrollbar-width: none; align-self: stretch; }
.tab { background: none; border: 0; border-bottom: 3px solid transparent; padding: 15px 11px 12px; cursor: pointer; white-space: nowrap; color: var(--muted); font-weight: 500; font-size: 0.94rem; }
.tab:hover { color: var(--ink); }
.tab[aria-current="page"] { color: var(--ink); border-bottom-color: var(--accent); }
.engine { font: 400 0.76rem var(--font-mono); color: var(--muted); white-space: nowrap; }
.engine.bad { color: var(--bad); white-space: normal; }

/* Page layout */
.page { padding-left: var(--gutter-l); padding-right: var(--gutter-r); padding-block: 24px 40px; }
.bench { display: grid; gap: 28px; align-items: start; max-width: 1480px; margin: 0 auto; }
.bench-2 { grid-template-columns: 280px minmax(0, 1fr); }
.bench-3 { grid-template-columns: 270px minmax(0, 1fr) 270px; }
.narrow { max-width: 760px; margin: 0 auto; display: grid; gap: 22px; }
.narrow-wide { max-width: 960px; margin: 0 auto; display: grid; gap: 22px; }
.work { min-width: 0; display: grid; gap: 18px; max-width: 860px; }
.foot { color: var(--muted); font-size: 0.84rem; border-top: 1px solid var(--line); padding-block: 16px; padding-left: var(--gutter-l); padding-right: var(--gutter-r); text-align: center; }

/* Navigators */
.nav { position: sticky; top: calc(var(--head) + 16px + env(safe-area-inset-top, 0px)); max-height: calc(100vh - var(--head) - 32px); overflow-y: auto; min-width: 0; font-size: 0.92rem; scrollbar-width: thin; }
.nav > summary { display: none; }
.nav-intro { color: var(--muted); font-size: 0.88rem; margin-bottom: 14px; }
.nav-group { margin-bottom: 16px; }
.nav-title { display: flex; justify-content: space-between; gap: 8px; align-items: baseline; font: 600 0.74rem var(--font-body); letter-spacing: 0.05em; text-transform: uppercase; color: var(--muted); padding: 0 8px 5px; }
.nav-title span:last-child { font-family: var(--font-mono); letter-spacing: 0; text-transform: none; font-weight: 400; }
.nav-item { display: flex; gap: 8px; align-items: baseline; width: 100%; text-align: left; background: none; border: 0; border-radius: 4px; padding: 5px 8px; cursor: pointer; line-height: 1.35; }
.nav-item:hover { background: var(--accent-soft); }
.nav-item[aria-current="true"] { background: var(--accent); color: var(--accent-ink); }
.nav-item[aria-current="true"] .tick { color: inherit; }
.tick { flex: none; width: 1em; color: var(--muted); font-family: var(--font-mono); font-size: 0.85em; }
.tick.done { color: var(--good); font-weight: 600; }
.nav-item .lvl { margin-left: auto; flex: none; font-family: var(--font-mono); font-size: 0.72rem; opacity: 0.75; }

/* Reading content */
.eyebrow { font: 500 0.78rem var(--font-mono); color: var(--muted); display: flex; flex-wrap: wrap; gap: 4px 12px; align-items: center; margin-bottom: 8px; }
.prose { display: grid; gap: 12px; min-width: 0; }
.prose ul, .prose ol { margin: 0; padding-left: 1.3em; display: grid; gap: 5px; }
.prose pre { margin: 0; padding: 12px 14px; background: var(--surface); border: 1px solid var(--line); border-radius: 4px; overflow-x: auto; font: 400 0.86rem/1.5 var(--font-mono); }
.prose h4 { margin: 0; font: 600 1rem var(--font-body); }
.lesson { display: grid; gap: 14px; }

/* Pills */
.pill { font: 500 0.72rem var(--font-mono); padding: 1px 7px; border-radius: 3px; border: 1px solid currentColor; }
.pill.Easy, .pill.Beginner { color: var(--good); }
.pill.Medium, .pill.Intermediate { color: var(--warn); }
.pill.Hard, .pill.Advanced { color: var(--bad); }
.pill.ok { background: var(--good-soft); color: var(--good); border-color: transparent; }

/* Editor */
.editor { display: grid; background: var(--raised); border: 1px solid var(--line); border-radius: 4px 4px 0 0; overflow: hidden; font: 400 0.92rem/1.55 var(--font-mono); }
.editor:focus-within { border-color: var(--accent); }
.editor pre, .editor textarea { grid-area: 1 / 1; margin: 0; padding: 11px 13px; font: inherit; white-space: pre; tab-size: 2; border: 0; width: 100%; min-width: 0; }
.editor pre { overflow: hidden; pointer-events: none; color: var(--ink); }
.editor textarea { resize: none; background: transparent; color: transparent; caret-color: var(--ink); outline: 0; overflow: auto; }
.editor textarea::selection { background: var(--accent-soft); color: transparent; }
.editor textarea::placeholder { color: var(--muted); }
.t-kw { color: var(--accent); font-weight: 500; }
.t-str { color: var(--string); }
.t-num { color: var(--number); }
.t-com { color: var(--muted); font-style: italic; }
.bar { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; padding: 8px; background: var(--surface); border: 1px solid var(--line); border-top: 0; border-radius: 0 0 4px 4px; }
.bar.free { border: 0; background: none; padding: 0; }
.spacer { flex: 1; }
.kbd { font: 400 0.72rem var(--font-mono); color: var(--muted); }
.btn { background: var(--raised); border: 1px solid var(--line); border-radius: 4px; padding: 6px 12px; cursor: pointer; font-size: 0.9rem; font-weight: 500; }
.btn:hover { border-color: var(--accent); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.btn.primary:hover { filter: brightness(1.1); }
.btn.good { background: var(--good); border-color: var(--good); color: var(--bg); }
.btn.link { background: none; border-color: transparent; color: var(--accent); padding-inline: 4px; }
.btn.danger { color: var(--bad); }
.btn:disabled { opacity: 0.5; cursor: default; }

/* Results */
.runner { display: grid; min-width: 0; }
.out { display: grid; gap: 10px; margin-top: 8px; min-width: 0; }
.out:empty { display: none; }
.scroll { overflow-x: auto; border: 1px solid var(--line); border-radius: 4px; background: var(--raised); }
table.grid { border-collapse: collapse; width: 100%; font-size: 0.86rem; font-variant-numeric: tabular-nums; }
.grid th { text-align: left; font: 600 0.74rem var(--font-mono); color: var(--muted); padding: 6px 11px; border-bottom: 1px solid var(--line); white-space: nowrap; background: var(--surface); }
.grid td { padding: 5px 11px; border-bottom: 1px solid var(--line); white-space: nowrap; }
.grid tr:last-child td { border-bottom: 0; }
.grid td.num { text-align: right; font-family: var(--font-mono); font-size: 0.82rem; }
.grid th.num { text-align: right; }
.null { color: var(--muted); font-style: italic; font-family: var(--font-mono); font-size: 0.8rem; }
.meta { font: 400 0.75rem var(--font-mono); color: var(--muted); }
.note { padding: 9px 13px; border-radius: 4px; font-size: 0.93rem; display: grid; gap: 6px; }
.note.err { background: var(--bad-soft); color: var(--ink); }
.note.err strong { color: var(--bad); }
.note.ok { background: var(--good-soft); }
.note.ok strong { color: var(--good); }
.note.warn { background: var(--warn-soft); }
.note.warn strong { color: var(--warn); }
.note.info { background: var(--accent-soft); }
.note code { background: var(--raised); }

/* Task and quiz */
.task { border-top: 2px solid var(--ink); padding-top: 14px; margin-top: 8px; display: grid; gap: 11px; }
.task-title { font: 600 0.78rem var(--font-body); letter-spacing: 0.05em; text-transform: uppercase; color: var(--muted); }
.options { display: grid; gap: 6px; }
.option { text-align: left; background: var(--raised); border: 1px solid var(--line); border-radius: 4px; padding: 8px 12px; cursor: pointer; }
.option:hover:not(:disabled) { border-color: var(--accent); }
.option.right { background: var(--good-soft); border-color: var(--good); }
.option.wrong { background: var(--bad-soft); border-color: var(--bad); }
.option:disabled { cursor: default; }
.pager { display: flex; justify-content: space-between; gap: 10px; flex-wrap: wrap; border-top: 1px solid var(--line); padding-top: 14px; }

/* Tables panel */
.tables { position: sticky; top: calc(var(--head) + 16px + env(safe-area-inset-top, 0px)); max-height: calc(100vh - var(--head) - 32px); overflow-y: auto; min-width: 0; font-size: 0.88rem; display: grid; gap: 4px; align-content: start; scrollbar-width: thin; }
.tables-title { font: 600 0.74rem var(--font-body); letter-spacing: 0.05em; text-transform: uppercase; color: var(--muted); margin-bottom: 4px; }
.tbl { border-bottom: 1px solid var(--line); padding-block: 5px; }
.tbl > summary { cursor: pointer; font: 500 0.86rem var(--font-mono); }
.tbl-note { color: var(--muted); font-size: 0.82rem; margin-block: 3px 6px; }
.col-row { display: flex; justify-content: space-between; gap: 8px; font: 400 0.78rem var(--font-mono); padding-block: 1px; }
.col-row span:last-child { color: var(--muted); }
.tbl .scroll { margin-top: 7px; }
.tbl .grid { font-size: 0.76rem; }
.tbl-inline { border: 1px solid var(--line); border-radius: 4px; padding: 8px 12px; }
.tbl-inline > summary { cursor: pointer; font-weight: 500; }
.tbl-inline .tables { position: static; max-height: none; margin-top: 8px; }

/* Schema */
.req { margin: 0; padding-left: 1.2em; display: grid; gap: 4px; }
.checks { display: grid; gap: 4px; list-style: none; margin: 0; padding: 0; }
.checks li { display: flex; gap: 8px; align-items: baseline; font-size: 0.93rem; }
.checks .s { flex: none; font: 600 0.72rem var(--font-mono); width: 3.1em; text-align: center; border-radius: 3px; padding: 0 3px; }
.checks .s.pass { background: var(--good-soft); color: var(--good); }
.checks .s.miss { background: var(--bad-soft); color: var(--bad); }
.diagram { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 10px; }
.entity { background: var(--raised); border: 1px solid var(--line); border-radius: 4px; min-width: 0; align-self: start; }
.entity-name { font: 600 0.84rem var(--font-mono); padding: 5px 10px; background: var(--accent-soft); border-radius: 3px 3px 0 0; }
.entity-col { display: flex; gap: 6px; flex-wrap: wrap; justify-content: space-between; padding: 3px 10px; border-top: 1px solid var(--line); font: 400 0.76rem var(--font-mono); }
.key { color: var(--mark); font-weight: 500; }
.fk { color: var(--accent); }

/* Theory, mock and progress */
.card { background: var(--surface); border: 1px solid var(--line); border-radius: 4px; padding: 18px; display: grid; gap: 13px; min-width: 0; }
.chips { display: flex; flex-wrap: wrap; gap: 6px; }
.chip { border: 1px solid var(--line); background: var(--raised); border-radius: 3px; padding: 3px 10px; cursor: pointer; font-size: 0.85rem; }
.chip[aria-pressed="true"] { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); }
.q-big { font: 600 1.45rem/1.25 var(--font-display); text-wrap: balance; }
.field { width: 100%; min-height: 96px; resize: vertical; background: var(--raised); border: 1px solid var(--line); border-radius: 4px; padding: 10px 12px; font: inherit; color: inherit; }
.timer { font: 500 1.5rem var(--font-mono); font-variant-numeric: tabular-nums; }
.timer.low { color: var(--bad); }
.steps { display: flex; flex-wrap: wrap; gap: 6px; }
.meter-row { display: grid; grid-template-columns: minmax(110px, 170px) minmax(0, 1fr) 62px; gap: 10px; align-items: center; font-size: 0.92rem; }
.meter { height: 9px; background: var(--line); border-radius: 2px; overflow: hidden; }
.meter i { display: block; height: 100%; background: var(--accent); }
.meter-val { font: 400 0.8rem var(--font-mono); color: var(--muted); text-align: right; font-variant-numeric: tabular-nums; }
.stack { display: grid; gap: 8px; }

@media (max-width: 1180px) {
  .bench-3 { grid-template-columns: 250px minmax(0, 1fr); }
  .bench-3 .tables { grid-column: 2; position: static; max-height: none; }
}
@media (max-width: 860px) {
  .bench-2, .bench-3 { grid-template-columns: minmax(0, 1fr); gap: 16px; }
  .bench-3 .tables { grid-column: 1; }
  .nav { position: static; max-height: none; border: 1px solid var(--line); border-radius: 4px; padding: 8px; background: var(--surface); }
  .nav > summary { display: block; cursor: pointer; font-weight: 600; padding: 2px 6px; }
  .nav[open] > summary { margin-bottom: 8px; }
  .engine { display: none; }
  .engine.bad { display: block; padding-bottom: 8px; }
  .brand { padding-top: 10px; }
  .tabs { flex-basis: 100%; }
  .tab { padding-block: 9px 8px; }
  h2 { font-size: 1.65rem; }
  .editor { font-size: 16px; }
  .kbd { display: none; }
  .page { padding-block: 16px 32px; }
}
@media (prefers-reduced-motion: no-preference) {
  .meter i { transition: width 0.3s ease; }
}