:root {
  --ink: #16202a;
  --ink-2: #34424f;
  --muted: #6d7881;
  --paper: #f4f0e8;
  --paper-2: #ebe5da;
  --white: #fffdf8;
  --night: #111a24;
  --night-2: #1b2733;
  --lime: #c8f169;
  --orange: #ff8b5c;
  --blue: #80a8ff;
  --line: rgba(22, 32, 42, 0.15);
  --shadow: 0 24px 80px rgba(26, 34, 42, 0.14);
  --radius: 18px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Manrope", system-ui, sans-serif;
  line-height: 1.5;
}
button, input, select { font: inherit; }
a { color: inherit; }
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}
.skip-link {
  position: fixed; left: 1rem; top: -4rem; z-index: 100;
  padding: .75rem 1rem; background: var(--lime); color: var(--night); border-radius: 8px;
}
.skip-link:focus { top: 1rem; }

.topbar {
  min-height: 76px; padding: 0 clamp(1.25rem, 4vw, 4.5rem);
  display: flex; align-items: center; justify-content: space-between; gap: 2rem;
  background: var(--night); color: #f9f5ec; border-bottom: 1px solid rgba(255,255,255,.1);
  position: sticky; top: 0; z-index: 20;
}
.brand { display: inline-flex; align-items: center; gap: .8rem; font-weight: 800; text-decoration: none; }
.brand-mark {
  font: 500 .67rem/1 "DM Mono", monospace; letter-spacing: .08em;
  padding: .55rem .58rem; color: var(--night); background: var(--lime); border-radius: 5px;
}
.topbar nav { display: flex; gap: clamp(1rem, 3vw, 2.2rem); }
.topbar nav a { color: #bfc7ce; text-decoration: none; font-size: .9rem; font-weight: 600; }
.topbar nav a:hover, .topbar nav a:focus-visible { color: var(--lime); }
.progress-button {
  display: flex; align-items: center; gap: .55rem; border: 1px solid rgba(255,255,255,.16);
  border-radius: 999px; color: #e9edf0; background: rgba(255,255,255,.05); padding: .55rem .85rem;
}
.progress-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--lime); box-shadow: 0 0 0 4px rgba(200,241,105,.12); }

.hero {
  min-height: 650px; padding: clamp(4rem, 8vw, 8rem) clamp(1.25rem, 7vw, 8rem);
  display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(360px, .85fr); gap: clamp(3rem, 8vw, 8rem); align-items: center;
  color: #f8f3e8; background-color: var(--night);
  background-image: linear-gradient(rgba(255,255,255,.025) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,.025) 1px, transparent 1px);
  background-size: 34px 34px;
}
.eyebrow { margin: 0 0 1rem; font: 500 .72rem/1.3 "DM Mono", monospace; letter-spacing: .13em; text-transform: uppercase; color: #7f8d99; }
.hero .eyebrow { color: var(--lime); }
h1, h2, h3, p { margin-top: 0; }
h1 { margin-bottom: 1.5rem; font-size: clamp(3rem, 6vw, 6.3rem); line-height: .96; letter-spacing: -.065em; }
h1 em { color: var(--lime); font-style: normal; font-weight: 500; }
.hero-intro { max-width: 650px; color: #bac4cc; font-size: clamp(1.05rem, 1.45vw, 1.28rem); }
.hero-actions { display: flex; flex-wrap: wrap; gap: .8rem; margin-top: 2rem; }
.button { display: inline-flex; align-items: center; gap: .7rem; padding: .9rem 1.15rem; border-radius: 8px; text-decoration: none; font-weight: 700; font-size: .9rem; }
.button-primary { background: var(--lime); color: var(--night); }
.button-secondary { border: 1px solid rgba(255,255,255,.22); color: #f7f2e8; }
.button:hover { transform: translateY(-2px); }

.query-card { overflow: hidden; border: 1px solid rgba(255,255,255,.14); border-radius: 15px; background: #0c131b; box-shadow: 0 32px 80px rgba(0,0,0,.32); transform: rotate(1deg); }
.query-card-header, .query-card-footer { display: flex; justify-content: space-between; gap: 1rem; padding: .85rem 1rem; font: 400 .7rem/1.2 "DM Mono", monospace; color: #8e9ba6; }
.query-card-header { border-bottom: 1px solid rgba(255,255,255,.08); }
.query-card-footer { border-top: 1px solid rgba(255,255,255,.08); }
.status-pill { color: var(--lime); }
.query-card pre { overflow-x: auto; margin: 0; padding: 1.6rem; font: 400 clamp(.76rem, 1.15vw, .94rem)/1.9 "DM Mono", monospace; color: #d8dee3; }
.code-keyword { color: #ff9b76; }.code-fn { color: #9eb9ff; }.code-muted { color: #637481; }

.stats-strip { display: grid; grid-template-columns: repeat(4, 1fr); padding: 0 clamp(1.25rem, 7vw, 8rem); border-bottom: 1px solid var(--line); background: var(--white); }
.stats-strip div { padding: 2rem clamp(.8rem, 3vw, 2.5rem); border-right: 1px solid var(--line); }
.stats-strip div:first-child { padding-left: 0; }.stats-strip div:last-child { border: 0; }
.stats-strip strong { display: block; font-size: clamp(1.8rem, 3vw, 2.8rem); line-height: 1; letter-spacing: -.05em; }
.stats-strip span { display: block; margin-top: .55rem; color: var(--muted); font-size: .78rem; }

.section, .catalog-section { padding: clamp(4.5rem, 8vw, 8rem) clamp(1.25rem, 7vw, 8rem); }
.section-heading, .catalog-heading { display: grid; grid-template-columns: 1.1fr .9fr; align-items: end; gap: 3rem; margin-bottom: 3rem; }
.section-heading h2, .catalog-heading h2 { margin: 0; font-size: clamp(2.1rem, 4vw, 4rem); line-height: 1.02; letter-spacing: -.055em; }
.section-heading > p, .catalog-heading > p { margin: 0; max-width: 620px; color: var(--muted); }
.toolkit { background: var(--white); }
.toolkit-layout { display: grid; grid-template-columns: minmax(220px, .34fr) minmax(0, 1fr); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; box-shadow: 0 18px 60px rgba(20,31,42,.06); }
.tool-index { padding: .75rem; background: #eee8dd; border-right: 1px solid var(--line); }
.tool-button { display: flex; align-items: center; justify-content: space-between; gap: .75rem; width: 100%; padding: .72rem .8rem; border: 0; border-radius: 7px; color: var(--ink-2); background: transparent; text-align: left; cursor: pointer; font-size: .82rem; font-weight: 650; }
.tool-button small { color: var(--muted); font: .58rem "DM Mono", monospace; text-transform: uppercase; }
.tool-button:hover, .tool-button.is-active { color: var(--night); background: var(--lime); }
.tool-lesson { min-height: 610px; padding: clamp(1.5rem, 4vw, 3.2rem); }
.lesson-kicker { display: flex; align-items: center; gap: .7rem; color: var(--orange); font: .7rem "DM Mono", monospace; text-transform: uppercase; }
.lesson-kicker span { padding: .25rem .45rem; border: 1px solid currentColor; border-radius: 999px; }
.tool-lesson h3, .pattern-lesson h3 { margin: .8rem 0 1rem; font-size: clamp(1.8rem, 3vw, 3rem); line-height: 1.04; letter-spacing: -.045em; }
.tool-theory { max-width: 800px; color: var(--ink-2); font-size: 1.02rem; }
.lesson-columns { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin: 1.5rem 0; }
.lesson-block { padding: 1.2rem; border: 1px solid var(--line); border-radius: 10px; background: #f8f4ec; }
.lesson-block h4 { margin: 0 0 .7rem; font-size: .77rem; text-transform: uppercase; letter-spacing: .08em; }
.lesson-block p, .lesson-block li { color: var(--muted); font-size: .84rem; }
.lesson-block p:last-child { margin-bottom: 0; }
.lesson-block ol { margin: 0; padding-left: 1.2rem; }.lesson-block li + li { margin-top: .45rem; }
.lesson-code { overflow-x: auto; margin: 1rem 0 0; padding: 1.2rem; border-radius: 10px; color: #dce3e8; background: var(--night); font: .78rem/1.7 "DM Mono", monospace; }
.pattern-grid { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line); border-left: 1px solid var(--line); }
.pattern-card { min-height: 220px; padding: 1.5rem; border: 0; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); text-align: left; background: transparent; color: var(--ink); cursor: pointer; transition: background .2s, transform .2s; }
.pattern-card:hover, .pattern-card:focus-visible { background: var(--white); transform: translateY(-3px); box-shadow: var(--shadow); z-index: 1; }
.pattern-number { display: flex; justify-content: space-between; font: 500 .7rem/1 "DM Mono", monospace; color: var(--muted); }
.pattern-symbol { font-size: 1.4rem; color: var(--orange); }
.pattern-card h3 { margin: 2.3rem 0 .6rem; font-size: 1.15rem; }
.pattern-card p { margin: 0; color: var(--muted); font-size: .83rem; }
.pattern-card.is-active { background: var(--white); box-shadow: inset 0 -4px var(--lime); }
.pattern-lesson { margin-top: 2rem; padding: clamp(1.4rem, 4vw, 3rem); border: 1px solid var(--line); border-radius: var(--radius); background: var(--white); }
.pattern-lesson-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 2rem; }
.practice-pattern { flex: 0 0 auto; padding: .75rem .9rem; border: 0; border-radius: 7px; color: var(--night); background: var(--lime); cursor: pointer; font-weight: 750; }

.catalog-section { background: var(--night); color: #f4f1ea; }
.catalog-section .eyebrow { color: var(--lime); }
.catalog-heading > p { color: #8f9ba4; }
.catalog-controls { display: grid; grid-template-columns: minmax(260px, 1fr) auto 170px 150px; gap: .75rem; margin-bottom: 2rem; }
.search-box { display: flex; align-items: center; gap: .65rem; min-height: 48px; padding: 0 .85rem; border: 1px solid rgba(255,255,255,.14); border-radius: 8px; background: rgba(255,255,255,.055); }
.search-box input { min-width: 0; flex: 1; border: 0; outline: 0; color: #fff; background: transparent; }
.search-box input::placeholder { color: #798691; }
kbd { padding: .15rem .4rem; border: 1px solid rgba(255,255,255,.16); border-radius: 4px; color: #7e8a94; font: .65rem "DM Mono", monospace; }
.filter-row { display: flex; padding: 4px; border: 1px solid rgba(255,255,255,.14); border-radius: 8px; }
.filter-chip { border: 0; border-radius: 5px; padding: .55rem .75rem; color: #8f9ba4; background: transparent; cursor: pointer; }
.filter-chip.is-active { color: var(--night); background: var(--lime); font-weight: 700; }
.select-wrap select { width: 100%; height: 100%; min-height: 48px; padding: 0 2.2rem 0 .75rem; color: #dbe1e5; background: var(--night-2); border: 1px solid rgba(255,255,255,.14); border-radius: 8px; }
.catalog-layout { display: grid; grid-template-columns: 225px minmax(0, 1fr); gap: 2rem; }
.pattern-index { border-right: 1px solid rgba(255,255,255,.1); padding-right: 1rem; }
.index-label { font: 500 .67rem "DM Mono", monospace; color: #687681; letter-spacing: .12em; text-transform: uppercase; }
.index-button { display: flex; justify-content: space-between; gap: .7rem; width: 100%; padding: .62rem .7rem; border: 0; border-radius: 6px; text-align: left; color: #99a4ad; background: transparent; cursor: pointer; font-size: .78rem; }
.index-button span:last-child { color: #596873; font: .7rem "DM Mono", monospace; }
.index-button:hover, .index-button.is-active { color: var(--lime); background: rgba(200,241,105,.08); }
.problem-table-head, .problem-row { display: grid; grid-template-columns: 70px minmax(210px, 1.35fr) minmax(160px, .75fr) 95px 86px; gap: 1rem; align-items: center; }
.problem-table-head { padding: 0 1rem .8rem; color: #667581; font: 500 .65rem "DM Mono", monospace; letter-spacing: .1em; text-transform: uppercase; }
.problem-row { width: 100%; padding: 1rem; border: 0; border-top: 1px solid rgba(255,255,255,.09); color: #dce2e7; background: transparent; text-align: left; transition: background .15s; }
.problem-row:hover, .problem-row:focus-visible { background: rgba(255,255,255,.055); outline: none; }
.status-check { display: inline-grid; place-items: center; width: 23px; height: 23px; border: 1px solid #586671; border-radius: 6px; color: var(--night); background: transparent; cursor: pointer; }
.problem-row.is-solved .status-check { border-color: var(--lime); background: var(--lime); }
.problem-name { display: flex; align-items: baseline; gap: .7rem; min-width: 0; padding: 0; border: 0; color: inherit; background: transparent; text-align: left; cursor: pointer; }
.problem-id { color: #64727d; font: .7rem "DM Mono", monospace; }
.problem-title { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-weight: 600; }
.pattern-tag { color: #9ca8b1; font-size: .76rem; }
.difficulty { width: fit-content; padding: .22rem .5rem; border-radius: 999px; font: 500 .67rem "DM Mono", monospace; }
.difficulty.easy { color: #bfe86d; background: rgba(191,232,109,.1); }
.difficulty.medium { color: #ffc26e; background: rgba(255,194,110,.1); }
.difficulty.hard { color: #ff8e7d; background: rgba(255,142,125,.11); }
.practice-link { color: var(--lime); font-size: .7rem; text-decoration: none; font-weight: 700; }
.practice-link:hover { text-decoration: underline; }
.empty-state { padding: 4rem 1rem; text-align: center; color: #8e9ba5; border-top: 1px solid rgba(255,255,255,.1); }
.load-more { width: 100%; margin-top: 1rem; padding: .9rem; border: 1px solid rgba(255,255,255,.15); border-radius: 8px; color: #c5cdd3; background: rgba(255,255,255,.04); cursor: pointer; }

.playbook { background: var(--white); }
.playbook-steps { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--line); }
.playbook-steps li { display: grid; grid-template-columns: 100px 1fr; gap: 1rem; padding: 1.5rem 0; border-bottom: 1px solid var(--line); }
.playbook-steps > li > span { color: var(--orange); font: 500 .76rem "DM Mono", monospace; }
.playbook-steps h3 { margin-bottom: .25rem; font-size: 1.05rem; }
.playbook-steps p { margin: 0; color: var(--muted); }
footer { display: flex; align-items: center; justify-content: space-between; gap: 2rem; padding: 2rem clamp(1.25rem, 7vw, 8rem); color: #a6b0b7; background: #0c131b; font-size: .78rem; }
footer p { margin: 0; } footer a { color: var(--lime); text-decoration: none; }

.problem-dialog { width: min(1220px, calc(100% - 2rem)); max-height: calc(100vh - 2rem); padding: 0; border: 0; border-radius: var(--radius); color: var(--ink); background: var(--white); box-shadow: 0 40px 100px rgba(0,0,0,.4); }
.problem-dialog::backdrop { background: rgba(5,10,16,.77); backdrop-filter: blur(5px); }
.dialog-shell { position: relative; padding: clamp(1.4rem, 4vw, 3rem); }
.dialog-close { position: absolute; top: 1rem; right: 1rem; width: 38px; height: 38px; border: 1px solid var(--line); border-radius: 50%; background: transparent; cursor: pointer; font-size: 1.4rem; }
.dialog-eyebrow { display: flex; flex-wrap: wrap; gap: .6rem; align-items: center; padding-right: 3rem; }
.dialog-eyebrow span { color: var(--muted); font: .72rem "DM Mono", monospace; }
.problem-dialog h2 { margin: 1rem 0 .7rem; font-size: clamp(1.8rem, 4vw, 3rem); line-height: 1.05; letter-spacing: -.045em; }
.dialog-summary { color: var(--muted); }
.workspace-grid { display: grid; grid-template-columns: minmax(0, .82fr) minmax(0, 1.18fr); gap: 1rem; margin-top: 1.4rem; }
.practice-pane, .solution-pane { min-width: 0; padding: 1.3rem; border: 1px solid var(--line); border-radius: 12px; }
.practice-pane { background: #f4efe5; }
.solution-pane { position: relative; min-height: 480px; background: var(--white); }
.pane-label { display: flex; align-items: center; justify-content: space-between; gap: .7rem; margin-bottom: 1rem; font: .68rem "DM Mono", monospace; text-transform: uppercase; letter-spacing: .1em; color: var(--muted); }
.pane-label strong { color: var(--ink); font: 750 .8rem "Manrope", sans-serif; letter-spacing: 0; }
.practice-cta { display: flex; justify-content: center; align-items: center; width: 100%; min-height: 54px; margin: 1rem 0; border-radius: 8px; color: var(--night); background: var(--lime); text-decoration: none; font-weight: 800; }
.attempt-list { margin: 1rem 0; padding-left: 1.2rem; color: var(--ink-2); font-size: .82rem; }
.attempt-list li + li { margin-top: .45rem; }
.notes-label { display: block; margin-top: 1.2rem; font-size: .78rem; font-weight: 750; }
.practice-notes { width: 100%; min-height: 128px; margin-top: .45rem; padding: .75rem; resize: vertical; border: 1px solid var(--line); border-radius: 8px; color: var(--ink); background: var(--white); }
.practice-actions { display: flex; gap: .6rem; margin-top: .8rem; }
.practice-actions button { padding: .65rem .75rem; border: 1px solid var(--line); border-radius: 7px; background: transparent; cursor: pointer; font-weight: 700; }
.solution-locked { display: grid; place-items: center; min-height: 400px; padding: 2rem; text-align: center; border: 1px dashed var(--line); border-radius: 9px; background: repeating-linear-gradient(-45deg, #faf7f0, #faf7f0 10px, #f4efe7 10px, #f4efe7 20px); }
.solution-locked-inner { max-width: 410px; }.solution-locked h3 { margin-bottom: .5rem; font-size: 1.35rem; }.solution-locked p { color: var(--muted); font-size: .86rem; }
.reveal-solution { padding: .8rem 1rem; border: 0; border-radius: 7px; color: var(--white); background: var(--night); cursor: pointer; font-weight: 800; }
.tool-chips { display: flex; flex-wrap: wrap; gap: .4rem; margin: .8rem 0; }
.tool-chip { padding: .3rem .48rem; border: 1px solid var(--line); border-radius: 999px; color: var(--ink-2); background: #f7f3eb; font: .65rem "DM Mono", monospace; cursor: pointer; }
.tool-chip:hover { border-color: var(--ink); color: var(--ink); }
.solution-reasoning { margin: 1rem 0; padding: 1rem; border-left: 3px solid var(--lime); background: #f7f4ed; }
.solution-reasoning h3 { font-size: .85rem; }.solution-reasoning ol { margin-bottom: 0; padding-left: 1.2rem; color: var(--muted); font-size: .8rem; }
.solution-tabs { display: flex; gap: .4rem; margin: 1.6rem 0 .7rem; }
.solution-tab { padding: .5rem .75rem; border: 1px solid var(--line); border-radius: 6px; background: transparent; cursor: pointer; }
.solution-tab.is-active { color: var(--white); background: var(--night); }
.solution-code { position: relative; overflow-x: auto; margin: 0; padding: 1.4rem; border-radius: 10px; color: #dce3e8; background: #111a24; font: .8rem/1.7 "DM Mono", monospace; }
.dialog-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-top: 1.25rem; }
.note-card { padding: 1rem; border: 1px solid var(--line); border-radius: 10px; background: #f7f3eb; }
.note-card h3 { font-size: .85rem; }.note-card p { margin: 0; color: var(--muted); font-size: .8rem; }
.dialog-actions { display: flex; flex-wrap: wrap; gap: .7rem; margin-top: 1.3rem; }
.dialog-actions a, .dialog-actions button { padding: .7rem .9rem; border: 1px solid var(--line); border-radius: 7px; color: var(--ink); background: transparent; text-decoration: none; cursor: pointer; font-weight: 700; }
.dialog-actions .mark-solved { border-color: var(--night); color: var(--white); background: var(--night); }

@media (max-width: 1040px) {
  .hero { grid-template-columns: 1fr; }.query-card { max-width: 680px; transform: none; }
  .catalog-controls { grid-template-columns: 1fr 1fr; }.search-box { grid-column: 1 / -1; }
  .pattern-grid { grid-template-columns: repeat(2, 1fr); }
  .toolkit-layout { grid-template-columns: 1fr; }.tool-index { display: flex; overflow-x: auto; border-right: 0; border-bottom: 1px solid var(--line); }.tool-button { min-width: 180px; }
  .workspace-grid { grid-template-columns: 1fr; }
}
@media (max-width: 760px) {
  .topbar nav { display: none; }.progress-button { font-size: .75rem; }
  .hero { min-height: auto; padding-top: 5rem; }.query-card { width: 100%; }
  .stats-strip { grid-template-columns: repeat(2, 1fr); }.stats-strip div:nth-child(2) { border-right: 0; }
  .section-heading, .catalog-heading { grid-template-columns: 1fr; gap: 1rem; }
  .pattern-grid { grid-template-columns: 1fr; }
  .lesson-columns { grid-template-columns: 1fr; }.pattern-lesson-head { flex-direction: column; }.practice-pattern { width: 100%; }
  .catalog-controls { grid-template-columns: 1fr; }.search-box { grid-column: auto; }.filter-row { overflow-x: auto; }
  .pattern-index { display: none; }.catalog-layout { grid-template-columns: 1fr; }
  .problem-table-head { display: none; }.problem-row { grid-template-columns: 34px 1fr auto; gap: .7rem; }
  .problem-row .pattern-tag { grid-column: 2; }.problem-row .difficulty { grid-column: 3; grid-row: 1; }.practice-link { grid-column: 2; }
  .dialog-grid { grid-template-columns: 1fr; } footer { align-items: flex-start; flex-direction: column; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } * { transition: none !important; } }