/* ════════════════════════════════════════════════════════
   SQLRound — main.css
   Light theme by default. Dark via [data-theme="dark"].
   All colors use CSS custom properties.
════════════════════════════════════════════════════════ */

/* ── Fonts ───────────────────────────────────────────── */
@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600&display=swap');

/* ── Reset ───────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; height: 100%; }
body { font-family: 'Outfit', sans-serif; line-height: 1.6; height: 100%; overflow: hidden; }
a { text-decoration: none; }
button { cursor: pointer; font-family: inherit; }
pre, code { font-family: 'JetBrains Mono', monospace; }

/* ── Light theme (default) ───────────────────────────── */
:root {
  --bg:          #ffffff;
  --bg-alt:      #ffffff;
  --surface:     #ffffff;
  --surface-2:   #f4f6fb;
  --surface-3:   #eaecf4;
  --border:      #dde3ed;
  --border-2:    #c8d0de;

  --text:        #1a2336;
  --text-2:      #4a5568;
  --text-muted:  #8a95a8;

  --accent:      #2563eb;
  --accent-dim:  rgba(37,99,235,0.08);
  --accent-hover:#1d4ed8;

  --ok:          #16a34a;
  --ok-dim:      rgba(22,163,74,0.08);
  --ok-bg:       #f0fdf4;

  --err:         #dc2626;
  --err-dim:     rgba(220,38,38,0.08);
  --err-bg:      #fef2f2;

  --warn:        #d97706;

  /* Code editor */
  --editor-bg:   #0d1f35;
  --editor-text: #cfe0f5;

  /* SQL token colours (same in both themes — dark editor) */
  --sql-kw:      #c084fc;
  --sql-fn:      #38bdf8;
  --sql-str:     #86efac;
  --sql-num:     #fb923c;
  --sql-cmt:     #5c7e96;
  --sql-id:      #cfe0f5;

  /* Nav */
  --nav-bg:      #ffffff;
  --nav-border:  #dde3ed;
  --nav-text:    #4a5568;
  --nav-active-bg: rgba(37,99,235,0.07);
  --nav-active-border: #2563eb;
  --nav-active-text: #2563eb;

  /* Topnav */
  --topnav-bg:   #ffffff;
  --topnav-h:    52px;

  /* Sidebar */
  --sidebar-w:   214px;
  --schema-w:    248px;

  /* Status icons */
  --status-pending: #c8d0de;
  --status-done:    #16a34a;

  /* Shadows */
  --shadow-sm:   0 1px 3px rgba(0,0,0,0.08);
  --shadow-md:   0 4px 12px rgba(0,0,0,0.1);

  /* Code block chrome */
  --code-chrome: #0b1825;
  --code-bg:     #06111f;
}

/* ── Dark theme ──────────────────────────────────────── */
[data-theme="dark"] {
  --bg:          #06101e;
  --bg-alt:      #0b1828;
  --surface:     #0b1828;
  --surface-2:   #0f1f32;
  --surface-3:   #132540;
  --border:      #1a2e45;
  --border-2:    #1f3855;

  --text:        #cfe0f5;
  --text-2:      #7a9fc0;
  --text-muted:  #3d5c78;

  --accent:      #4f9fff;
  --accent-dim:  rgba(79,159,255,0.09);
  --accent-hover:#6aadff;

  --ok:          #3dd68c;
  --ok-dim:      rgba(61,214,140,0.09);
  --ok-bg:       rgba(61,214,140,0.06);

  --err:         #ff5c5c;
  --err-dim:     rgba(255,92,92,0.09);
  --err-bg:      rgba(255,92,92,0.06);

  --warn:        #fb923c;

  --nav-bg:      #0b1828;
  --nav-border:  #1a2e45;
  --nav-text:    #7a9fc0;
  --nav-active-bg: rgba(79,159,255,0.09);
  --nav-active-border: #4f9fff;
  --nav-active-text: #4f9fff;

  --topnav-bg:   #0b1828;
  --status-pending: #1f3855;
  --status-done:    #3dd68c;

  --code-chrome: #081522;
  --code-bg:     #06111f;
}

/* ── Scrollbar ───────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border-2); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* ── Layout ──────────────────────────────────────────── */
body {
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.layout {
  display: flex;
  flex: 1;
  min-height: 0;
  overflow: hidden;
}

.layout__main {
  flex: 1;
  overflow-y: auto;
  padding: 32px 40px;
  min-width: 0;
}

/* Ad slot between content sections */
.ad-slot {
  margin: 28px 0;
  min-height: 90px;
  background: var(--surface-2);
  border: 1px dashed var(--border-2);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-size: 12px;
}
.ad-slot--hidden { display: none; } /* hide when no adsense id */

/* ── Top Nav ─────────────────────────────────────────── */
.topnav {
  height: var(--topnav-h);
  background: var(--topnav-bg);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  padding: 0 20px;
  justify-content: space-between;
  flex-shrink: 0;
  z-index: 100;
}

.topnav__logo {
  font-size: 18px;
  font-weight: 800;
  color: var(--text);
  letter-spacing: -0.02em;
}
.topnav__logo-sql { color: var(--accent); }

.topnav__db-badge {
  font-size: 11px;
  color: var(--text-muted);
  font-family: 'JetBrains Mono', monospace;
  margin-left: 14px;
}

.topnav__left  { display: flex; align-items: center; }
.topnav__right { display: flex; align-items: center; gap: 12px; }

.topnav__links { display: flex; gap: 4px; }

.topnav__link {
  padding: 6px 14px;
  border-radius: 6px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-2);
  transition: background 0.15s, color 0.15s;
}
.topnav__link:hover { background: var(--surface-2); color: var(--text); }
.topnav__link--active { background: var(--accent-dim); color: var(--accent); font-weight: 600; }

/* ── Theme Toggle ────────────────────────────────────── */
.theme-toggle {
  width: 34px; height: 34px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text-2);
  font-size: 15px;
  display: flex; align-items: center; justify-content: center;
  transition: background 0.15s;
}
.theme-toggle:hover { background: var(--surface-3); }
.theme-toggle__icon--dark  { display: none; }
[data-theme="dark"] .theme-toggle__icon--light { display: none; }
[data-theme="dark"] .theme-toggle__icon--dark  { display: inline; }

/* ── Left Sidebar ────────────────────────────────────── */
.sidebar-left {
  width: var(--sidebar-w);
  flex-shrink: 0;
  background: var(--nav-bg);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  font-size: 13px;
}

.sidebar-left__header {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--text-muted);
}

/* Chapter */
.chapter { border-bottom: 1px solid var(--border); }

.chapter__header {
  list-style: none;
  padding: 10px 14px;
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  user-select: none;
  color: var(--text);
  font-weight: 600;
  font-size: 13px;
}
.chapter__header::-webkit-details-marker { display: none; }
.chapter__header:hover { background: var(--surface-2); }

.chapter__num {
  font-size: 10px;
  color: var(--text-muted);
  font-family: 'JetBrains Mono', monospace;
  min-width: 20px;
}

.chapter__name { flex: 1; }

.chapter__arrow::before { content: '▸'; font-size: 10px; color: var(--text-muted); }
details[open] .chapter__arrow::before { content: '▾'; }

/* Topic */
.chapter__topics { padding: 4px 0 6px; }

.topic {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 7px 14px 7px 32px;
  color: var(--nav-text);
  border-left: 2px solid transparent;
  transition: background 0.1s;
  font-size: 12.5px;
}
.topic:hover { background: var(--surface-2); color: var(--text); }
.topic--active {
  background: var(--nav-active-bg);
  border-left-color: var(--nav-active-border);
  color: var(--nav-active-text);
  font-weight: 600;
}

.topic__num {
  font-size: 10px;
  color: var(--text-muted);
  font-family: 'JetBrains Mono', monospace;
  min-width: 16px;
}
.topic__title { flex: 1; }
.topic__status { margin-left: auto; flex-shrink: 0; }

.status-icon { width: 14px; height: 14px; }
.status-icon--pending { color: var(--status-pending); }
.status-icon--done    { color: var(--status-done); }

/* ── Schema Panel (right sidebar) ────────────────────── */
.schema-panel {
  width: var(--schema-w);
  flex-shrink: 0;
  background: var(--nav-bg);
  border-left: 1px solid var(--border);
  overflow-y: auto;
  font-size: 12.5px;
}

.schema-panel__header {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--text-muted);
}

.schema-table { border-bottom: 1px solid var(--border); }

.schema-table__name {
  list-style: none;
  padding: 9px 14px;
  display: flex;
  align-items: center;
  gap: 7px;
  cursor: pointer;
  user-select: none;
  color: var(--text);
  font-weight: 600;
}
.schema-table__name::-webkit-details-marker { display: none; }
.schema-table__name:hover { background: var(--surface-2); }

.schema-table__icon { color: var(--accent); font-size: 11px; }

.schema-table__arrow { margin-left: auto; }
.schema-table__arrow::before { content: '▸'; font-size: 10px; color: var(--text-muted); }
details[open] .schema-table__arrow::before { content: '▾'; }

.schema-table__cols { padding: 4px 0 8px; }

.schema-col {
  padding: 3px 14px 3px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.schema-col__name {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11.5px;
  color: var(--text-2);
}
.schema-col__name--pk { color: var(--accent); }

.schema-col__meta { display: flex; align-items: center; gap: 4px; }

.schema-col__type {
  font-size: 10px;
  color: var(--text-muted);
  font-family: 'JetBrains Mono', monospace;
}

.badge {
  font-size: 9px;
  font-weight: 700;
  padding: 1px 4px;
  border-radius: 3px;
}
.badge--pk { background: var(--accent-dim); color: var(--accent); }
.badge--fk { background: rgba(251,146,60,0.1); color: #f97316; }

/* ── Lesson Content ──────────────────────────────────── */
.lesson__breadcrumb {
  font-size: 12px;
  color: var(--text-muted);
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 6px;
}
.lesson__breadcrumb a { color: var(--text-2); }
.lesson__breadcrumb a:hover { color: var(--accent); }
.lesson__breadcrumb-current { color: var(--accent); }

.lesson__title {
  font-size: 24px;
  font-weight: 700;
  color: var(--text);
  line-height: 1.3;
  margin-bottom: 10px;
}

.lesson__body { max-width: 780px; }

.lesson__body h2 { font-size: 20px; font-weight: 700; margin: 32px 0 12px; color: var(--text); }
.lesson__body h3 { font-size: 17px; font-weight: 600; margin: 24px 0 10px; color: var(--text); }
.lesson__body p  { margin-bottom: 16px; color: var(--text-2); font-size: 14.5px; line-height: 1.75; }
.lesson__body ul, .lesson__body ol { padding-left: 24px; margin-bottom: 16px; color: var(--text-2); font-size: 14.5px; }
.lesson__body li { margin-bottom: 6px; line-height: 1.65; }
.lesson__body hr { border: none; border-top: 1px solid var(--border); margin: 28px 0; }

.lesson__body table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 20px;
  font-size: 13.5px;
}
.lesson__body th {
  padding: 8px 14px;
  background: var(--surface-2);
  color: var(--text);
  font-weight: 600;
  border: 1px solid var(--border);
  text-align: left;
}
.lesson__body td {
  padding: 7px 14px;
  border: 1px solid var(--border);
  color: var(--text-2);
}
.lesson__body tr:nth-child(even) td { background: var(--surface-2); }

.inline-code {
  background: var(--surface-3);
  color: var(--accent);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
}

/* ── Label row above code blocks ─────────────────────── */
.block-label {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin: 24px 0 8px;
  text-transform: uppercase;
}

/* ── SQL Code Block (syntax + demo) ─────────────────── */
.sql-block {
  border-radius: 10px;
  overflow: hidden;
  border: 1px solid var(--border);
  margin-bottom: 24px;
}

.sql-block__bar {
  background: var(--code-chrome);
  padding: 8px 14px;
  border-bottom: 1px solid rgba(255,255,255,0.06);
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 38px;
}

.sql-block__dots { display: flex; gap: 6px; align-items: center; }
.sql-block__dots i {
  width: 10px; height: 10px;
  border-radius: 50%;
  display: inline-block;
  font-style: normal;
}
.sql-block__dots i:nth-child(1) { background: #ff5f57; }
.sql-block__dots i:nth-child(2) { background: #febc2e; }
.sql-block__dots i:nth-child(3) { background: #28c840; }

.sql-block__body {
  background: var(--code-bg);
  padding: 18px 22px;
  overflow-x: auto;
}

.sql-block__body pre {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--sql-id);
}

/* SQL token colours */
.tok-kw  { color: var(--sql-kw); }
.tok-fn  { color: var(--sql-fn); }
.tok-str { color: var(--sql-str); }
.tok-num { color: var(--sql-num); }
.tok-cmt { color: var(--sql-cmt); }
.tok-id  { color: var(--sql-id); }

/* ── Results Table ───────────────────────────────────── */
.sql-block__results,
.question-block__results {
  background: var(--surface);
  border-top: 1px solid var(--border);
}

.results__meta {
  padding: 6px 16px;
  border-bottom: 1px solid var(--border);
  font-size: 11px;
  color: var(--text-muted);
  display: flex;
  gap: 12px;
}

.results__meta-ok   { color: var(--ok); font-weight: 600; }
.results__meta-err  { color: var(--err); font-weight: 600; }

.results__table-wrap { overflow-x: auto; }

.results__table {
  width: 100%;
  border-collapse: collapse;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
}
.results__table th {
  padding: 8px 16px;
  text-align: left;
  color: var(--accent);
  font-weight: 600;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
  background: var(--surface-2);
}
.results__table td {
  padding: 7px 16px;
  color: var(--text-2);
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}
.results__table tr:last-child td { border-bottom: none; }
.results__table tr:nth-child(even) td { background: var(--surface-2); }

/* ── Question Block ──────────────────────────────────── */
.question-block {
  border-radius: 10px;
  border: 1px solid var(--border);
  overflow: hidden;
  margin-bottom: 20px;
}

.question-block__header {
  padding: 14px 18px;
  background: var(--surface-2);
  border-bottom: 1px solid var(--border);
  display: flex;
  gap: 12px;
}

.question-block__num {
  width: 28px; height: 28px;
  border-radius: 6px;
  background: var(--accent-dim);
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  display: flex; align-items: center; justify-content: center;
  font-family: 'JetBrains Mono', monospace;
  flex-shrink: 0;
}

.question-block__title {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 5px;
}

.question-block__desc {
  font-size: 13.5px;
  color: var(--text-2);
  line-height: 1.65;
}

.question-block__editor {
  background: var(--code-bg);
}

.sql-editor {
  width: 100%;
  min-height: 96px;
  background: transparent;
  border: none;
  outline: none;
  color: var(--sql-id);
  font-family: 'JetBrains Mono', monospace;
  font-size: 13.5px;
  line-height: 1.75;
  padding: 14px 18px;
  resize: vertical;
  display: block;
}
.sql-editor::placeholder { color: var(--sql-cmt); }

.question-block__footer {
  padding: 9px 14px;
  background: var(--surface);
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.question-block__actions { display: flex; gap: 8px; }

.question-block__status {
  font-size: 12.5px;
  display: flex;
  align-items: center;
  gap: 5px;
}
.question-block__status--ok  { color: var(--ok); }
.question-block__status--err { color: var(--err); }

/* Expected output (shown on wrong answer) */
.question-block__expected {
  background: var(--err-bg);
  border-top: 1px solid rgba(220,38,38,0.15);
  padding: 12px 18px;
}
.expected__label {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--err);
  opacity: 0.7;
  margin-bottom: 8px;
}

/* ── Buttons ─────────────────────────────────────────── */
.btn {
  padding: 6px 14px;
  border-radius: 6px;
  font-size: 12px;
  font-weight: 600;
  font-family: 'Outfit', sans-serif;
  transition: background 0.15s, opacity 0.15s;
  border: none;
}
.btn:disabled { opacity: 0.6; cursor: not-allowed; }

.btn--primary {
  background: var(--accent);
  color: #fff;
}
.btn--primary:hover:not(:disabled) { background: var(--accent-hover); }

.btn--secondary {
  background: transparent;
  border: 1px solid var(--border-2);
  color: var(--text-2);
}
.btn--secondary:hover:not(:disabled) { background: var(--surface-2); }

.btn--run { /* used in demo block bar */
  background: var(--accent);
  color: #fff;
  padding: 5px 14px;
  font-size: 12px;
}
.btn--run:hover:not(:disabled) { background: var(--accent-hover); }

/* ── Prev/Next navigation ────────────────────────────── */
.lesson__nav {
  display: flex;
  justify-content: space-between;
  margin-top: 40px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  gap: 16px;
}

.lesson__nav-btn {
  display: flex;
  flex-direction: column;
  gap: 3px;
  padding: 12px 18px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  max-width: 260px;
  transition: border-color 0.15s, background 0.15s;
}
.lesson__nav-btn:hover { border-color: var(--accent); background: var(--accent-dim); }
.lesson__nav-btn--next { text-align: right; margin-left: auto; }

.lesson__nav-btn__label { font-size: 11px; color: var(--text-muted); }
.lesson__nav-btn__title { font-size: 13.5px; font-weight: 600; color: var(--text); }

/* ── Compiler Page ───────────────────────────────────── */
.compiler-layout {
  display: flex;
  flex: 1;
  min-height: 0;
  overflow: hidden;
}

.compiler-main {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.compiler-toolbar {
  padding: 9px 18px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--surface);
  flex-shrink: 0;
}

.compiler-toolbar__info { font-size: 12.5px; color: var(--text-muted); }
.compiler-toolbar__info span { color: var(--text-2); }
.compiler-toolbar__actions { display: flex; gap: 8px; }

.compiler-editor-wrap {
  display: flex;
  background: var(--code-bg);
  flex-shrink: 0;
  overflow: hidden;
}

.compiler-editor-wrap--full { flex: 1; }

.compiler-line-nums {
  width: 44px;
  background: #050f1c;
  border-right: 1px solid rgba(255,255,255,0.06);
  padding-top: 16px;
  flex-shrink: 0;
  overflow: hidden;
  user-select: none;
}
.compiler-line-nums span {
  display: block;
  height: 24px;
  line-height: 24px;
  text-align: right;
  padding-right: 10px;
  font-size: 12px;
  color: var(--sql-cmt);
  font-family: 'JetBrains Mono', monospace;
}

.compiler-textarea {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  color: var(--sql-id);
  font-family: 'JetBrains Mono', monospace;
  font-size: 13.5px;
  line-height: 24px;
  padding: 16px 18px;
  resize: none;
}
.compiler-textarea::placeholder { color: var(--sql-cmt); }

.compiler-results {
  flex: 1;
  border-top: 1px solid var(--border);
  overflow-y: auto;
  background: var(--surface);
}

/* ── Footer ──────────────────────────────────────────── */
.site-footer {
  border-top: 1px solid var(--border);
  background: var(--surface);
  padding: 14px 20px;
  flex-shrink: 0;
}
.site-footer__inner {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 12.5px;
}
.site-footer__brand { font-weight: 700; color: var(--text); }
.brand-sql { color: var(--accent); }
.site-footer__copy { color: var(--text-muted); }

/* ── Homepage ────────────────────────────────────────── */
.home-layout {
  display: flex;
  flex: 1;
  min-height: 0;
  overflow: hidden;
}
.home-main {
  flex: 1;
  overflow-y: auto;
  padding: 40px;
}
.home-hero {
  margin-bottom: 40px;
}
.home-hero__title {
  font-size: 28px;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 10px;
}
.home-hero__sub {
  font-size: 15px;
  color: var(--text-2);
  max-width: 560px;
  line-height: 1.65;
}

.chapter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 14px;
}
.chapter-card {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px;
  background: var(--surface);
  transition: border-color 0.15s, box-shadow 0.15s;
}
.chapter-card:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-sm);
}
.chapter-card__num  { font-size: 11px; color: var(--text-muted); font-family: 'JetBrains Mono', monospace; margin-bottom: 6px; }
.chapter-card__name { font-size: 15px; font-weight: 700; color: var(--text); margin-bottom: 4px; }
.chapter-card__count{ font-size: 12px; color: var(--text-muted); }

/* ════════════════════════════════════════════════════════
   PART 2: Fixed sidebars, results, page polish, mobile
════════════════════════════════════════════════════════ */

/* ── Fixed sidebars — flex container does the work ──── */
/* body overflow:hidden + layout flex:1 min-height:0 = only main scrolls */
.sidebar-left {
  height: 100%;
  overflow-y: auto;
  flex-shrink: 0;
}
.schema-panel {
  height: 100%;
  overflow-y: auto;
  flex-shrink: 0;
}

/* ── Results window — scrollable, polished ───────────── */
.sql-block__results,
.question-block__results {
  border-top: 1px solid var(--border);
  max-height: 280px;
  overflow-y: auto;
  overflow-x: auto;
}

.question-block__expected {
  max-height: 200px;
  overflow-y: auto;
}

.results__meta {
  padding: 7px 16px;
  border-bottom: 1px solid var(--border);
  font-size: 11.5px;
  color: var(--text-muted);
  display: flex;
  gap: 14px;
  align-items: center;
  background: var(--surface-2);
  position: sticky;
  top: 0;
  z-index: 1;
}
.results__meta-ok  { color: var(--ok);  font-weight: 700; }
.results__meta-err { color: var(--err); font-weight: 700; }

.results__table-wrap { overflow-x: auto; }

.results__table {
  width: 100%;
  border-collapse: collapse;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
}
.results__table thead { position: sticky; top: 0; z-index: 1; }
.results__table th {
  padding: 6px 12px;
  text-align: left;
  background: #0d1f35;
  color: #5ccfe6;
  font-weight: 600;
  border-bottom: 1px solid #1a2e45;
  white-space: nowrap;
  font-size: 11.5px;
}
.results__table td {
  padding: 4px 12px;
  color: var(--text-2);
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
  font-size: 12px;
  line-height: 1.6;
}
.results__table tr:last-child td { border-bottom: none; }
.results__table tbody tr:hover td { background: var(--accent-dim); }
.results__table .td-null { color: var(--text-muted); font-style: italic; font-size: 11px; }

.btn--ghost {
  padding: 6px 12px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-muted);
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  font-family: 'Outfit', sans-serif;
  transition: background 0.15s, color 0.15s;
}
.btn--ghost:hover { background: var(--surface-2); color: var(--text); }

/* ── Schema type colours ─────────────────────────────── */
.schema-col__type { font-family: 'JetBrains Mono', monospace; font-size: 10px; font-weight: 600; }
.type--int     { color: #3b82f6; }
.type--decimal { color: #f97316; }
.type--date    { color: #a855f7; }
.type--varchar { color: #10b981; }

.schema-table__label { flex: 1; }

.schema-table__count {
  font-size: 10px;
  font-weight: 600;
  color: var(--text-muted);
  background: var(--surface-3);
  border-radius: 10px;
  padding: 1px 7px;
  margin-right: 6px;
  font-family: 'JetBrains Mono', monospace;
}

/* ── Page polish — lesson ────────────────────────────── */
.lesson__breadcrumb {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--text-muted);
  margin-bottom: 16px;
  padding: 8px 12px;
  background: var(--surface-2);
  border-radius: 6px;
  border: 1px solid var(--border);
  width: fit-content;
}
.lesson__breadcrumb a { color: var(--text-2); font-weight: 500; }
.lesson__breadcrumb a:hover { color: var(--accent); }
.lesson__breadcrumb-current { color: var(--accent); font-weight: 600; }

.lesson__title {
  font-size: 26px;
  font-weight: 800;
  color: var(--text);
  line-height: 1.25;
  margin-bottom: 8px;
  letter-spacing: -0.02em;
}

.lesson__meta {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 28px;
  display: flex;
  align-items: center;
  gap: 14px;
}
.lesson__meta-tag {
  padding: 3px 10px;
  border-radius: 20px;
  background: var(--accent-dim);
  color: var(--accent);
  font-weight: 600;
  font-size: 11px;
}

/* Better section headings in lesson body */
.lesson__body h2 {
  font-size: 19px;
  font-weight: 700;
  margin: 36px 0 14px;
  color: var(--text);
  padding-bottom: 8px;
  border-bottom: 2px solid var(--border);
  letter-spacing: -0.01em;
}
.lesson__body h3 {
  font-size: 16px;
  font-weight: 600;
  margin: 24px 0 10px;
  color: var(--text);
}
.lesson__body p {
  margin-bottom: 16px;
  color: var(--text-2);
  font-size: 14.5px;
  line-height: 1.8;
}

/* Block labels */
.block-label {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--text-muted);
  text-transform: uppercase;
  margin: 28px 0 8px;
}

/* ── Code block polish ───────────────────────────────── */
.sql-block {
  border-radius: 10px;
  overflow: hidden;
  border: 1px solid #1a2e45;
  margin-bottom: 24px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.12);
}
.sql-block__bar {
  background: #0a1828;
  padding: 9px 16px;
  border-bottom: 1px solid #1a2e45;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 40px;
}
.sql-block__dots { display: flex; gap: 6px; align-items: center; }
.sql-block__dots i {
  width: 11px; height: 11px; border-radius: 50%; display: inline-block; font-style: normal;
}
.sql-block__dots i:nth-child(1) { background: #ff5f57; }
.sql-block__dots i:nth-child(2) { background: #febc2e; }
.sql-block__dots i:nth-child(3) { background: #28c840; }
.sql-block__body {
  background: #071120;
  padding: 20px 24px;
  overflow-x: auto;
}
.sql-block__body pre {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.8;
}

/* ── Question block polish ───────────────────────────── */
.question-block {
  border-radius: 10px;
  border: 1px solid var(--border);
  overflow: hidden;
  margin-bottom: 20px;
  box-shadow: 0 1px 4px rgba(0,0,0,0.06);
  transition: box-shadow 0.15s;
}
.question-block:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}

/* Completed — glassy green */
.question-block--done {
  border-color: rgba(22, 163, 74, 0.4) !important;
  box-shadow: 0 0 0 3px rgba(22, 163, 74, 0.07), 0 2px 10px rgba(22, 163, 74, 0.06) !important;
}
.question-block--done .question-block__header {
  background: linear-gradient(135deg, rgba(22,163,74,0.07) 0%, rgba(22,163,74,0.02) 100%);
}
.question-block--done .question-block__num {
  background: var(--ok);
  box-shadow: 0 2px 6px rgba(22,163,74,0.3);
}
[data-theme="dark"] .question-block--done {
  border-color: rgba(61,214,140,0.35) !important;
  box-shadow: 0 0 0 3px rgba(61,214,140,0.06), 0 2px 10px rgba(61,214,140,0.05) !important;
}
[data-theme="dark"] .question-block--done .question-block__header {
  background: linear-gradient(135deg, rgba(61,214,140,0.07) 0%, rgba(61,214,140,0.02) 100%);
}
[data-theme="dark"] .question-block--done .question-block__num {
  background: var(--ok);
  box-shadow: 0 2px 6px rgba(61,214,140,0.25);
}

.question-block__header {
  padding: 16px 20px;
  background: linear-gradient(135deg, var(--surface-2) 0%, var(--surface) 100%);
  border-bottom: 1px solid var(--border);
  display: flex;
  gap: 14px;
  align-items: flex-start;
}
.question-block__num {
  width: 30px; height: 30px;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-size: 12px;
  font-weight: 700;
  display: flex; align-items: center; justify-content: center;
  font-family: 'JetBrains Mono', monospace;
  flex-shrink: 0;
  margin-top: 1px;
}
.question-block__title {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 5px;
  line-height: 1.4;
}
.question-block__desc {
  font-size: 13.5px;
  color: var(--text-2);
  line-height: 1.65;
}

.question-block__editor {
  background: #071120;
  border-bottom: 1px solid #1a2e45;
  position: relative;
}

/* Highlight overlay + textarea stacked */
.editor-wrap {
  position: relative;
  min-height: 90px;
}
.editor-highlight {
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  margin: 0;
  padding: 14px 20px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 13.5px;
  line-height: 1.8;
  pointer-events: none;
  overflow: hidden;
  white-space: pre-wrap;
  word-wrap: break-word;
  color: var(--sql-id);
  background: transparent;
  border: none;
  z-index: 1;
}
.sql-editor {
  position: relative;
  width: 100%;
  min-height: 90px;
  background: transparent;
  border: none;
  outline: none;
  color: transparent;
  caret-color: #cfe0f5;
  font-family: 'JetBrains Mono', monospace;
  font-size: 13.5px;
  line-height: 1.8;
  padding: 14px 20px;
  resize: vertical;
  display: block;
  z-index: 2;
}
.sql-editor::placeholder { color: #3a5068; }

/* Hint block */
.question-block__hint {
  padding: 10px 18px;
  background: rgba(251,191,36,0.08);
  border-top: 1px solid rgba(251,191,36,0.2);
  font-size: 13.5px;
  color: #92400e;
  display: flex;
  align-items: flex-start;
  gap: 8px;
  line-height: 1.6;
}
[data-theme="dark"] .question-block__hint { color: #fcd34d; background: rgba(251,191,36,0.07); }
.hint__icon { flex-shrink: 0; font-size: 14px; }

/* Solution block */
.question-block__solution {
  border-top: 1px solid #1a2e45;
  background: #06111f;
}
.solution__label {
  padding: 7px 18px 0;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: #3a5068;
}
.solution__code {
  margin: 0;
  padding: 10px 18px 14px;
  font-size: 13px;
  line-height: 1.75;
  overflow-x: auto;
  color: #cfe0f5; /* base colour for operators, commas, plain chars */
}

.question-block__footer {
  padding: 10px 16px;
  background: var(--surface);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  border-top: 1px solid var(--border);
}
.question-block__actions { display: flex; gap: 8px; }
.question-block__status {
  font-size: 13px;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 6px;
}
.question-block__status--ok  { color: var(--ok); }
.question-block__status--err { color: var(--err); }

.question-block__expected {
  background: var(--err-bg);
  border-top: 1px solid rgba(220,38,38,0.2);
  padding: 12px 18px;
}
.expected__label {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--err);
  opacity: 0.8;
  margin-bottom: 8px;
  text-transform: uppercase;
}

/* ── TOC ─────────────────────────────────────────────── */
.toc {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 0 8px 8px 0;
  padding: 14px 18px;
  margin: 0 0 32px;
  max-width: 400px;
}
.toc__label {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--text-muted);
  margin-bottom: 10px;
}
.toc ul { list-style: none; padding: 0; margin: 0; }
.toc__item { margin-bottom: 5px; }
.toc__item a { font-size: 13px; color: var(--text-2); line-height: 1.5; font-weight: 500; }
.toc__item a:hover { color: var(--accent); }
.toc__item--sub { padding-left: 14px; }
.toc__item--sub a { font-size: 12.5px; color: var(--text-muted); font-weight: 400; }

/* ── Buttons ─────────────────────────────────────────── */
.btn--run {
  padding: 5px 14px;
  border-radius: 6px;
  border: none;
  background: var(--accent);
  color: #fff;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  font-family: 'Outfit', sans-serif;
  transition: background 0.15s;
}
.btn--run:hover { background: var(--accent-hover); }
.btn--run:disabled { opacity: 0.6; cursor: not-allowed; }

/* ── Hamburger ───────────────────────────────────────── */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 34px; height: 34px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: transparent;
  padding: 7px;
  margin-right: 8px;
}
.hamburger span {
  display: block;
  height: 2px;
  background: var(--text-2);
  border-radius: 2px;
}

.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.45);
  z-index: 90;
}
.sidebar-overlay.active { display: block; }

/* ── Mobile ≤ 768px ──────────────────────────────────── */
@media (max-width: 768px) {
  :root { --sidebar-w: 250px; --schema-w: 250px; }

  .hamburger { display: flex; }

  .sidebar-left {
    position: fixed;
    top: 0; left: 0;
    height: 100vh;
    z-index: 95;
    transform: translateX(-100%);
    transition: transform 0.25s ease;
    box-shadow: 4px 0 20px rgba(0,0,0,0.15);
  }
  .sidebar-left.open { transform: translateX(0); }

  .schema-panel { display: none; }

  .layout__main  { padding: 18px 16px; }
  .lesson__title { font-size: 20px; }

  .compiler-layout    { flex-direction: column; }
  .compiler-editor-wrap { min-height: 160px; }

  .topnav__db-badge   { display: none; }
  .lesson__nav        { flex-direction: column; }
  .lesson__nav-btn--next { margin-left: 0; text-align: left; }

  .toc            { max-width: 100%; }
  .chapter-grid   { grid-template-columns: 1fr 1fr; gap: 10px; }
  .question-block__footer { flex-wrap: wrap; }
  .sql-block__results,
  .question-block__results { max-height: 200px; }
}

@media (max-width: 480px) {
  .chapter-grid { grid-template-columns: 1fr; }
  .layout__main { padding: 14px 12px; }
}

/* ── Tablet 769–1024px ───────────────────────────────── */
@media (min-width: 769px) and (max-width: 1024px) {
  :root { --sidebar-w: 180px; --schema-w: 200px; }
  .layout__main  { padding: 24px 28px; }
  .topnav__db-badge { display: none; }
}