/* ============================================================
   SQL Revision Workspace — warm light + futuristic dark themes
   Fonts: Nunito (headings) · Source Sans 3 (body) · JetBrains Mono (code)
   ============================================================ */

/* Light (warm, friendly) — one coral/amber accent */
:root {
  --bg: #f6f1ea;
  --bg-2: #efe7db;
  --surface: #fffdf9;
  --surface-2: #f5eee3;
  --border: #e8ddcd;
  --border-strong: #d9cbb4;
  --text: #2c2620;
  --text-soft: #6c6153;
  --muted: #9c9081;
  --accent: #e26a45;          /* coral */
  --accent-2: #f0a35a;        /* amber */
  --accent-ink: #ffffff;
  --accent-soft: #fbe6dc;
  --ring-track: #ece1d1;
  --good: #2f9e6f;
  --good-soft: #e3f4ec;
  --bad: #d1495b;
  --bad-soft: #fbe5e9;

  --code-bg: #2b2621;
  --code-text: #f2ece2;
  --code-kw: #f0a35a;
  --code-str: #9ecf8a;
  --code-com: #9a8f80;
  --code-num: #e8b27a;

  --font-head: "Nunito", system-ui, sans-serif;
  --font-body: "Source Sans 3", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, monospace;

  --radius: 16px;
  --shadow: 0 1px 2px rgba(60, 42, 28, 0.05), 0 10px 30px rgba(60, 42, 28, 0.06);
  --sidebar-w: 288px;
}

/* Dark (futuristic, eye-friendly) — deep cool slate + violet accent */
[data-theme="dark"] {
  --bg: #0e121d;
  --bg-2: #121826;
  --surface: #161d2c;
  --surface-2: #1c2536;
  --border: #273143;
  --border-strong: #384860;
  --text: #e8ecf6;
  --text-soft: #a9b4cb;
  --muted: #76839f;
  --accent: #8b7cf6;          /* violet */
  --accent-2: #b39dff;
  --accent-ink: #ffffff;
  --accent-soft: #211e3d;
  --ring-track: #273143;
  --good: #37d39a;
  --good-soft: #10291f;
  --bad: #ff6b81;
  --bad-soft: #331722;

  --code-bg: #0a0e18;
  --code-text: #e7ecff;
  --code-kw: #9db0ff;
  --code-str: #7ee0a8;
  --code-com: #647089;
  --code-num: #f0b366;

  --shadow: 0 1px 2px rgba(0, 0, 0, 0.35), 0 14px 40px rgba(0, 0, 0, 0.4);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.58;
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3, .brand-text strong { font-family: var(--font-head); }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; }

/* ---------------- App shell ---------------- */
.app {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr);
  min-height: 100vh;
  transition: grid-template-columns 0.24s ease;
}
.app.nav-collapsed { --sidebar-w: 0px; }

/* ---------------- Sidebar ---------------- */
.sidebar {
  position: sticky; top: 0; align-self: start;
  height: 100vh; overflow-y: auto; overflow-x: hidden;
  background: var(--bg-2);
  border-right: 1px solid var(--border);
  padding: 20px 14px;
  display: flex; flex-direction: column; gap: 14px;
  min-width: 0;
}
.app.nav-collapsed .sidebar { padding-left: 0; padding-right: 0; border-right-color: transparent; }

.brand { display: flex; align-items: center; gap: 12px; padding: 0 4px; white-space: nowrap; }
.brand-mark {
  display: grid; place-items: center; width: 42px; height: 42px; flex: none;
  border-radius: 13px; color: var(--accent-ink); font-family: var(--font-head);
  font-weight: 800; font-size: 15px; letter-spacing: 0.4px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  box-shadow: 0 6px 16px -6px var(--accent);
}
.brand-text { display: flex; flex-direction: column; min-width: 0; }
.brand-text strong { font-size: 15px; font-weight: 800; }
.brand-text span { font-size: 12px; color: var(--muted); }

.search-wrap { position: relative; }
.search-icon {
  position: absolute; left: 11px; top: 50%; transform: translateY(-50%);
  color: var(--muted); font-size: 16px; pointer-events: none;
}
.topic-search {
  width: 100%; padding: 9px 12px 9px 32px; border-radius: 11px;
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
  font-family: inherit; font-size: 13px;
}
.topic-search:focus { outline: 2px solid var(--accent); outline-offset: 1px; }

.module-nav { display: flex; flex-direction: column; gap: 16px; flex: 1; }
.module-group { display: flex; flex-direction: column; gap: 3px; }
.module-label {
  font-size: 11px; font-weight: 700; letter-spacing: 0.6px; text-transform: uppercase;
  color: var(--muted); padding: 2px 8px; white-space: nowrap;
}
.topic-btn {
  display: flex; align-items: center; gap: 9px; width: 100%; text-align: left;
  border: 1px solid transparent; background: transparent; color: var(--text-soft);
  border-radius: 10px; padding: 7px 9px; cursor: pointer;
  font-family: inherit; font-size: 13px; white-space: nowrap;
  transition: background 0.12s, color 0.12s;
}
.topic-btn:hover { background: var(--surface); color: var(--text); }
.topic-btn.is-active {
  background: var(--accent-soft); color: var(--accent); font-weight: 600;
  border-color: color-mix(in srgb, var(--accent) 32%, transparent);
}
.topic-btn .num {
  flex: none; width: 22px; height: 22px; display: grid; place-items: center;
  font-size: 11px; font-weight: 700; border-radius: 7px;
  background: var(--surface-2); color: var(--muted); font-family: var(--font-head);
}
.topic-btn.is-active .num { background: var(--accent); color: var(--accent-ink); }
.topic-btn .txt { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; transition: transform 0.12s; }
.topic-btn:hover .txt { transform: translateX(2px); }
.topic-btn .done { flex: none; color: var(--good); font-size: 12px; font-weight: 700; }

.sidebar-foot {
  display: flex; align-items: center; gap: 8px; white-space: nowrap;
  font-size: 12px; color: var(--muted);
  border-top: 1px solid var(--border); padding-top: 12px;
}
.foot-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--good); flex: none; }

/* ---------------- Main / topbar ---------------- */
.main { min-width: 0; display: flex; flex-direction: column; }
.topbar {
  position: sticky; top: 0; z-index: 20;
  display: flex; align-items: center; gap: 14px;
  padding: 11px 22px;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--border);
}
.icon-btn {
  flex: none; width: 38px; height: 38px; display: grid; place-items: center;
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
  border-radius: 11px; cursor: pointer; font-size: 16px; font-family: inherit;
  transition: border-color 0.12s, color 0.12s, background 0.12s;
}
.icon-btn:hover { border-color: var(--accent); color: var(--accent); }

.breadcrumb {
  flex: 1; min-width: 0; display: flex; align-items: center; gap: 8px;
  font-size: 13.5px; color: var(--text-soft); overflow: hidden; white-space: nowrap;
}
.breadcrumb .crumb-sep { color: var(--muted); }
.breadcrumb .crumb-topic { color: var(--text); font-weight: 600; overflow: hidden; text-overflow: ellipsis; }

.topbar-right { flex: none; display: flex; align-items: center; gap: 12px; }

.ring { position: relative; width: 40px; height: 40px; display: grid; place-items: center; }
.ring svg { transform: rotate(-90deg); }
.ring-track { fill: none; stroke: var(--ring-track); stroke-width: 4; }
.ring-fill {
  fill: none; stroke: var(--accent); stroke-width: 4; stroke-linecap: round;
  transition: stroke-dashoffset 0.5s ease;
}
.ring-label {
  position: absolute; inset: 0; display: grid; place-items: center;
  font-family: var(--font-head); font-size: 10.5px; font-weight: 700; color: var(--text-soft);
}
.ring.complete .ring-fill { stroke: var(--good); }
.ring.complete .ring-label { color: var(--good); }

.topbar-progress {
  position: absolute; left: 0; bottom: -1px; height: 2px; width: 0;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  transition: width 0.1s linear;
}

/* ---------------- Content ---------------- */
.content { width: 100%; max-width: 960px; margin: 0 auto; padding: 30px 34px 90px; display: flex; flex-direction: column; gap: 20px; }

.hero { display: flex; flex-direction: column; gap: 8px; }
.eyebrow { margin: 0; font-size: 12px; font-weight: 700; letter-spacing: 0.5px; text-transform: uppercase; color: var(--accent); }
.hero h1 { margin: 0; font-size: 32px; font-weight: 800; line-height: 1.12; letter-spacing: -0.4px; }
.topic-desc { margin: 2px 0 0; color: var(--text-soft); font-size: 16px; max-width: 68ch; }

.hero-meta { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 6px; }
.hero-meta span, .hero-meta a {
  font-size: 12px; color: var(--text-soft); background: var(--surface);
  border: 1px solid var(--border); padding: 4px 11px; border-radius: 999px; text-decoration: none;
}
.hero-meta a:hover { color: var(--accent); border-color: var(--accent); }

.section-jump { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 6px; }
.section-jump a {
  font-size: 12px; color: var(--text-soft); text-decoration: none;
  padding: 4px 10px; border-radius: 8px; background: var(--surface-2); transition: all 0.12s;
}
.section-jump a:hover { color: var(--accent); }
.section-jump a.active { background: var(--accent); color: var(--accent-ink); }

/* ---------------- Cards ---------------- */
.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); box-shadow: var(--shadow);
  padding: 22px 24px; scroll-margin-top: 76px;
}
.card-head { margin-bottom: 16px; }
.card-head-row { display: flex; align-items: flex-start; justify-content: space-between; gap: 14px; }
.card-title { display: flex; align-items: center; gap: 9px; }
.card-title h2 { margin: 0; font-size: 19px; font-weight: 800; letter-spacing: -0.2px; }
.dot-accent { width: 9px; height: 9px; border-radius: 3px; background: var(--accent); flex: none; }
.card-head p { margin: 5px 0 0; font-size: 13px; color: var(--muted); }

.mini-btn {
  flex: none; border: 1px solid var(--border-strong); background: var(--surface-2);
  color: var(--text-soft); border-radius: 9px; padding: 7px 13px;
  font-family: inherit; font-size: 12px; font-weight: 600; cursor: pointer;
  transition: border-color 0.12s, color 0.12s;
}
.mini-btn:hover { border-color: var(--accent); color: var(--accent); }

/* Pointers */
.pointer-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(244px, 1fr)); gap: 11px; }
.pointer-card { border: 1px solid var(--border); border-radius: 13px; padding: 13px 15px; background: var(--surface-2); transition: transform 0.12s, border-color 0.12s; }
.pointer-card:hover { transform: translateY(-2px); border-color: var(--accent); }
.pointer-card .kw {
  display: inline-block; font-family: var(--font-mono); font-size: 12.5px; font-weight: 600;
  color: var(--accent); background: var(--accent-soft); padding: 2px 9px; border-radius: 7px; margin-bottom: 8px;
}
.pointer-card .tip { font-size: 13px; color: var(--text-soft); margin: 0; }
.tip code, .lesson-note code, .quiz-explain code {
  font-family: var(--font-mono); font-size: 12px; background: var(--surface);
  padding: 1px 5px; border-radius: 5px; border: 1px solid var(--border);
}

/* ---------------- Lesson ---------------- */
.lesson-section { border-bottom: 1px solid var(--border); scroll-margin-top: 80px; }
.lesson-section:last-child { border-bottom: none; }
.lesson-section > h3 {
  cursor: pointer; user-select: none; display: flex; align-items: center; gap: 10px;
  margin: 0; padding: 15px 2px; font-size: 15px; font-weight: 700; letter-spacing: 0.2px;
  text-transform: uppercase; transition: color 0.12s;
}
.lesson-section > h3:hover { color: var(--accent); }
.lesson-section > h3 .sec-heading { min-width: 0; }
.sec-count {
  margin-left: auto; flex: none; font-size: 11px; font-weight: 700; font-family: var(--font-head);
  background: var(--surface-2); color: var(--muted); border: 1px solid var(--border);
  border-radius: 999px; padding: 1px 9px; text-transform: none;
}
.lesson-section > h3 .chevron { flex: none; font-size: 11px; color: var(--muted); transition: transform 0.2s; margin-left: 8px; }
.lesson-section.collapsed > h3 .chevron { transform: rotate(-90deg); }

.lesson-steps { display: grid; grid-template-rows: 1fr; transition: grid-template-rows 0.25s ease, opacity 0.2s; opacity: 1; }
.lesson-steps > div { overflow: hidden; min-height: 0; }
.lesson-section.collapsed .lesson-steps { grid-template-rows: 0fr; opacity: 0; }
.lesson-steps > div { padding-bottom: 6px; }

.lesson-note {
  font-size: 14px; color: var(--text-soft); margin: 0 0 12px;
  padding: 10px 14px; background: var(--surface-2); border-radius: 10px; border-left: 3px solid var(--border-strong);
}

.section-steps-toggle {
  display: inline-flex; align-items: center; gap: 6px; border: 1px dashed var(--border-strong);
  background: transparent; color: var(--text-soft); border-radius: 9px; padding: 6px 12px;
  font-family: inherit; font-size: 12px; font-weight: 600; cursor: pointer; margin-bottom: 12px;
}
.section-steps-toggle:hover { border-color: var(--accent); color: var(--accent); }

.substep { border: 1px solid var(--border); border-radius: 12px; margin-bottom: 10px; overflow: hidden; background: var(--surface); }
.substep:last-child { margin-bottom: 4px; }
.substep-head {
  width: 100%; display: flex; align-items: center; gap: 10px; text-align: left;
  border: none; background: var(--surface-2); color: var(--text); padding: 11px 14px; cursor: pointer;
  font-family: inherit; font-size: 13.5px; font-weight: 500; line-height: 1.4; transition: background 0.12s;
}
.substep-head:hover { background: var(--accent-soft); }
.substep-head .dot { flex: none; width: 7px; height: 7px; border-radius: 50%; background: var(--accent); opacity: 0.5; transition: opacity 0.12s; }
.substep-head:hover .dot { opacity: 1; }
.substep-head .substep-title { flex: 1; min-width: 0; }
.substep-head .chevron { flex: none; font-size: 10px; color: var(--muted); transition: transform 0.2s; }
.substep.collapsed .substep-head .chevron { transform: rotate(-90deg); }
.substep-body { display: grid; grid-template-rows: 1fr; transition: grid-template-rows 0.22s ease; }
.substep-body > div { overflow: hidden; min-height: 0; }
.substep.collapsed .substep-body { grid-template-rows: 0fr; }

/* ---------------- Code ---------------- */
pre.code {
  margin: 0; background: var(--code-bg); color: var(--code-text);
  padding: 15px 17px; overflow-x: auto; font-family: var(--font-mono);
  font-size: 13px; line-height: 1.55; border-radius: 12px;
}
.substep-body pre.code { border-radius: 0; }
pre.code .kw { color: var(--code-kw); font-weight: 600; }
pre.code .str { color: var(--code-str); }
pre.code .com { color: var(--code-com); font-style: italic; }
pre.code .num { color: var(--code-num); }

.code-wrap { position: relative; }
.code-wrap .copy-btn {
  position: absolute; top: 8px; right: 8px; z-index: 2;
  border: 1px solid rgba(255,255,255,0.16); background: rgba(255,255,255,0.08); color: #dfe6ff;
  border-radius: 8px; padding: 4px 10px; font-family: var(--font-body); font-size: 11px; font-weight: 600;
  cursor: pointer; opacity: 0; transition: opacity 0.15s, background 0.15s;
}
.code-wrap:hover .copy-btn { opacity: 1; }
.code-wrap .copy-btn:hover { background: rgba(255,255,255,0.2); }
.code-wrap .copy-btn.copied { background: var(--good); border-color: var(--good); color: #fff; opacity: 1; }
@media (max-width: 860px) { .code-wrap .copy-btn { opacity: 1; } }

/* ---------------- Quiz ---------------- */
.quiz-tracker { flex: none; display: flex; flex-direction: column; align-items: flex-end; gap: 6px; font-size: 12px; color: var(--text-soft); min-width: 132px; }
.qbar { width: 132px; height: 6px; border-radius: 999px; background: var(--surface-2); overflow: hidden; border: 1px solid var(--border); }
.qbar span { display: block; height: 100%; width: 0; background: linear-gradient(90deg, var(--good), color-mix(in srgb, var(--good) 60%, #fff)); transition: width 0.3s ease; }

.quiz-item { border: 1px solid var(--border); border-radius: 13px; padding: 16px 18px; margin-bottom: 14px; background: var(--surface-2); }
.quiz-item:last-of-type { margin-bottom: 0; }
.quiz-tag { font-size: 11px; color: var(--muted); font-weight: 700; text-transform: uppercase; letter-spacing: 0.5px; }
.quiz-q { font-weight: 600; font-size: 15px; margin: 4px 0 0; }
.quiz-item pre.code { margin: 11px 0; border-radius: 10px; }
.quiz-options { display: flex; flex-direction: column; gap: 8px; margin-top: 11px; }
.quiz-option {
  display: flex; align-items: flex-start; gap: 11px; text-align: left; width: 100%;
  border: 1px solid var(--border-strong); background: var(--surface); color: var(--text);
  border-radius: 11px; padding: 11px 13px; cursor: pointer; font-family: inherit; font-size: 14px;
  transition: border-color 0.12s, background 0.12s, transform 0.08s;
}
.quiz-option:hover:not(:disabled) { border-color: var(--accent); }
.quiz-option:active:not(:disabled) { transform: translateY(1px); }
.quiz-option:disabled { cursor: default; }
.quiz-option .marker {
  flex: none; width: 23px; height: 23px; border-radius: 7px; display: grid; place-items: center;
  font-size: 12px; font-weight: 700; font-family: var(--font-head); background: var(--surface-2); color: var(--muted);
}
.quiz-option.correct { border-color: var(--good); background: var(--good-soft); animation: pop 0.28s ease; }
.quiz-option.correct .marker { background: var(--good); color: #fff; }
.quiz-option.wrong { border-color: var(--bad); background: var(--bad-soft); }
.quiz-option.wrong .marker { background: var(--bad); color: #fff; }
@keyframes pop { 0% { transform: scale(1); } 40% { transform: scale(1.015); } 100% { transform: scale(1); } }
.quiz-explain { margin-top: 12px; font-size: 13.5px; color: var(--text-soft); border-left: 3px solid var(--accent); padding: 7px 0 7px 13px; animation: fadeUp 0.25s ease both; }
.quiz-explain.correct { border-color: var(--good); }
.quiz-explain.wrong { border-color: var(--bad); }
.quiz-score { display: flex; align-items: center; justify-content: center; gap: 14px; margin-top: 14px; padding: 13px; border-radius: 12px; background: var(--accent-soft); color: var(--accent); font-weight: 700; font-family: var(--font-head); }
.quiz-reset { border: 1px solid currentColor; background: transparent; color: inherit; border-radius: 9px; padding: 6px 15px; font-family: inherit; font-size: 12px; font-weight: 700; cursor: pointer; }
.quiz-reset:hover { background: color-mix(in srgb, currentColor 10%, transparent); }

/* ---------------- Doubt ---------------- */
.doubt-search { display: flex; align-items: center; gap: 10px; position: relative; }
.doubt-search .search-icon { position: static; transform: none; font-size: 18px; }
.doubt-search input {
  flex: 1; border-radius: 11px; border: 1px solid var(--border); background: var(--surface-2);
  color: var(--text); padding: 11px 14px; font-family: inherit; font-size: 14px;
}
.doubt-search input:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
.doubt-search button {
  flex: none; border: 1px solid var(--accent); background: var(--accent); color: var(--accent-ink);
  border-radius: 11px; padding: 11px 20px; font-family: inherit; font-size: 14px; font-weight: 700; cursor: pointer;
}
.doubt-search button:disabled { opacity: 0.55; cursor: default; }
.doubt-answer { margin-top: 13px; font-size: 14px; }
.doubt-answer.muted, .muted { color: var(--muted); }
.doubt-answer p { margin: 0 0 8px; }
.doubt-answer.warning { color: var(--bad); }
.doubt-answer pre.code { margin: 8px 0; }

/* ---------------- Footer ---------------- */
.content-foot { display: flex; flex-direction: column; gap: 12px; margin-top: 4px; }
.foot-nav { display: flex; justify-content: space-between; gap: 12px; }
.foot-nav button {
  background: var(--surface); color: var(--text); border: 1px solid var(--border-strong);
  border-radius: 11px; padding: 10px 16px; font-family: inherit; font-size: 13px; font-weight: 600; cursor: pointer;
  max-width: 46%; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.foot-nav button:hover:not(:disabled) { border-color: var(--accent); color: var(--accent); }
.foot-nav button:disabled { opacity: 0.4; cursor: default; }
.kbd-hint { text-align: center; font-size: 11.5px; color: var(--muted); margin: 0; }
.kbd-hint kbd {
  font-family: var(--font-mono); font-size: 11px; background: var(--surface-2);
  border: 1px solid var(--border); border-bottom-width: 2px; border-radius: 5px; padding: 1px 6px; color: var(--text-soft);
}

/* ---------------- Toast + motion ---------------- */
.toast {
  position: fixed; bottom: 24px; left: 50%; transform: translate(-50%, 20px); z-index: 60;
  background: var(--text); color: var(--bg); padding: 10px 18px; border-radius: 999px;
  font-size: 13px; font-weight: 600; opacity: 0; pointer-events: none;
  transition: opacity 0.2s, transform 0.2s; box-shadow: var(--shadow);
}
.toast.show { opacity: 1; transform: translate(-50%, 0); }

@keyframes fadeUp { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }
.content.anim .hero { animation: fadeUp 0.3s ease both; }
.content.anim .card { animation: fadeUp 0.36s ease both; }
.content.anim .pointers-card { animation-delay: 0.03s; }
.content.anim .lesson-card { animation-delay: 0.06s; }
.content.anim .quiz-card { animation-delay: 0.09s; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .content.anim .hero, .content.anim .card, .app { animation: none; transition: none; }
}

/* ---------------- Mobile ---------------- */
@media (max-width: 860px) {
  .app { grid-template-columns: 1fr; }
  .sidebar {
    position: fixed; z-index: 30; left: 0; top: 0; width: 284px; padding: 20px 14px;
    transform: translateX(-100%); transition: transform 0.24s ease;
    border-right: 1px solid var(--border);
  }
  .app:not(.nav-collapsed) .sidebar { transform: translateX(0); box-shadow: var(--shadow); }
  .app.nav-collapsed .sidebar { padding-left: 14px; padding-right: 14px; }
  .content { padding: 22px 16px 70px; }
  .hero h1 { font-size: 25px; }
  .breadcrumb .crumb-module { display: none; }
}