:root {
  --canvas: #080d13;
  --canvas-top: #0d1625;
  --panel: #161e27;
  --panel-soft: #19212b;
  --panel-deep: #0c1421;
  --stroke: #2b3541;
  --stroke-strong: #3b4756;
  --text: #f4f7f9;
  --text-soft: #c3cad2;
  --text-muted: #9ca8b6;
  --lime: #91d438;
  --lime-soft: #b3ed67;
  --plan: #ff7898;
  --details: #fff1a8;
  --spec: #91d75d;
  --layout: #63b7ff;
  --general: #c294ff;
  color-scheme: dark;
}

* { scrollbar-color: #5c6672 var(--panel-deep); }
body {
  background:
    radial-gradient(ellipse 54rem 38rem at -7% -3%, rgba(47, 104, 84, .38) 0%, rgba(25, 71, 69, .2) 44%, transparent 72%),
    radial-gradient(ellipse 70rem 46rem at 68% -14%, rgba(24, 43, 82, .45) 0%, transparent 70%),
    linear-gradient(180deg, #0d1729 0%, #0a111a 36rem, var(--canvas) 100%);
  background-attachment: fixed;
  color: var(--text);
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
}
button, input, a { font-family: inherit; }

.topbar {
  height: 64px;
  padding: 0 18px;
  background: rgba(10, 16, 25, .94);
  border-top: 5px solid #05070a;
  border-bottom: 1px solid rgba(255,255,255,.06);
  backdrop-filter: blur(18px);
}
.brand {
  width: 326px;
  height: 59px;
  padding: 0 8px;
  border: 0;
  gap: 10px;
}
.brand > span { width: 34px; height: 34px; border: 0; }
.brand > span img { width: 34px !important; height: 34px !important; }
.brand b { font-size: 13px; letter-spacing: -.01em; }
.brand small { color: var(--text-muted); font-size: 9px; letter-spacing: .12em; }
.search {
  width: min(560px, 43vw);
  height: 39px;
  margin-left: 14px;
  border: 1px solid var(--stroke);
  border-radius: 9px;
  background: var(--panel-deep);
}
.search:focus-within { border-color: var(--lime); box-shadow: 0 0 0 3px rgba(145,212,56,.12); }
.search span { color: var(--text-muted); }
.search input { color: var(--text); font-size: 14px; }
.search input::placeholder { color: #64707e; }
.search { position: relative; }
.search-results {
  position: absolute;
  z-index: 100;
  top: calc(100% + 10px);
  left: 0;
  width: min(680px, 82vw);
  max-height: min(70vh, 620px);
  padding: 8px;
  overflow-y: auto;
  border: 1px solid var(--stroke-strong);
  border-radius: 10px;
  background: rgba(10, 16, 24, .99);
  box-shadow: 0 22px 60px rgba(0,0,0,.55);
}
.search-results[hidden] { display: none; }
.search-results button {
  display: block;
  width: 100%;
  padding: 12px 14px;
  color: var(--text);
  text-align: left;
  border: 0;
  border-bottom: 1px solid var(--stroke);
  background: transparent;
  cursor: pointer;
}
.search-results button:last-child { border-bottom: 0; }
.search-results button:hover,
.search-results button:focus { background: var(--panel-soft); outline: 1px solid var(--lime); }
.search-results strong { display: block; font-size: 14px; }
.search-results small { display: block; margin-top: 4px; color: var(--text-muted); font-size: 12px; line-height: 1.4; }
.search-results p { margin: 0; padding: 16px; color: var(--text-muted); }
.status { color: var(--text-muted); }

.rail {
  top: 64px;
  width: 326px;
  padding: 10px;
  background: rgba(10, 16, 24, .98);
  border-right: 1px solid var(--stroke);
}
.rail-title {
  height: 48px;
  padding: 0 10px;
  border: 0;
  color: var(--text-muted);
  font-size: 10px;
}
.rail-title b { color: var(--lime-soft); }
.rail nav { height: calc(100% - 48px); padding: 0 0 60px; }
.rail button {
  width: 100%;
  margin: 0 0 7px;
  padding: 11px 12px;
  grid-template-columns: 34px 1fr;
  gap: 7px;
  color: var(--text) !important;
  background: linear-gradient(90deg, rgba(var(--category-rgb),.11), var(--panel-deep) 34%) !important;
  border: 1px solid var(--stroke);
  border-left: 3px solid var(--category, var(--stroke-strong));
  border-radius: 10px;
}
[data-category="pro-plan"] { --category: var(--plan); --category-rgb: 255,120,152; }
[data-category="details-plan"] { --category: var(--details); --category-rgb: 255,241,168; }
[data-category="spec-plan"] { --category: var(--spec); --category-rgb: 145,215,93; }
[data-category="layout"] { --category: var(--layout); --category-rgb: 99,183,255; }
[data-category="general"] { --category: var(--general); --category-rgb: 194,148,255; }
.rail button:hover { border-color: #4b5868; transform: translateX(2px); }
.rail button.active { filter: none; background: var(--panel-soft) !important; border-color: var(--category); box-shadow: 0 0 0 2px color-mix(in srgb, var(--category) 15%, transparent); }
.rail button > span { color: var(--category, var(--text-muted)) !important; font-size: 10px; font-weight: 800; }
.rail strong { color: var(--text) !important; font-size: 12px; letter-spacing: .01em; text-transform: none; }
.rail small { color: #b4bdc8 !important; font-size: 10px; }

.workspace { margin-left: 326px; padding-top: 64px; }
.workspace-head {
  min-height: 214px;
  padding: 52px clamp(24px, 5vw, 74px) 30px;
  align-items: end;
}
.workspace-head small, .chapter-kicker { color: var(--lime); font-weight: 800; letter-spacing: .16em; }
.workspace-head h1 { margin: 11px 0 10px; color: var(--text); font-size: clamp(42px, 6vw, 78px); letter-spacing: -.055em; }
.workspace-head p { color: var(--text-soft); font-size: 15px; }
.change-log-link {
  color: var(--lime-soft);
  font-weight: 750;
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
}
.change-log-link:hover { color: var(--text); }
.toggle {
  padding: 3px;
  border: 1px solid var(--stroke);
  border-radius: 10px;
  background: var(--panel-deep);
}
.toggle button { color: var(--text-soft); border-radius: 7px; text-transform: none; letter-spacing: 0; font-size: 12px; font-weight: 700; }
.toggle .active { background: var(--lime); color: #17230b; }

.reader { margin: 0 clamp(18px, 5vw, 74px) 44px; }
.chapter {
  padding: clamp(28px, 4.2vw, 58px);
  color: var(--text);
  background: linear-gradient(145deg, rgba(var(--category-rgb),.07), var(--panel) 38%);
  border: 1px solid var(--stroke);
  border-top: 3px solid var(--category);
  border-radius: 16px;
  box-shadow: 0 24px 65px rgba(0,0,0,.26);
}
.chapter.index {
  background: linear-gradient(145deg, rgba(194,148,255,.075), #1a232d 38%);
}
.chapter-kicker { color: var(--category); }
.chapter h1 { color: var(--text); text-transform: none; font-size: clamp(38px, 5vw, 68px); }
.deck { color: var(--text-soft); font-size: 17px; line-height: 1.55; }
.prose h2 { color: var(--text); border-top-color: var(--stroke); font-size: 18px; letter-spacing: .01em; text-transform: none; }
.prose h3 { color: var(--text); }
.prose > p, .step p { color: var(--text-soft); font-family: inherit; font-size: 16px; line-height: 1.72; }
.step {
  margin: 10px 0;
  padding: 14px 16px;
  background: var(--panel-soft);
  border: 1px solid var(--stroke);
  border-left: 3px solid var(--category);
  border-radius: 9px;
}
.step b { color: var(--category); }
.prose .step {
  display: list-item;
  list-style: disc outside;
  margin: 8px 0 8px 1.7rem;
  padding: 0 0 0 .15rem;
  background: transparent;
  border: 0;
  border-radius: 0;
}
.prose .step::marker { color: var(--category); font-size: 1.05em; }
.prose .step p { margin: 0; color: var(--text-soft) !important; font: 16px/1.65 inherit; }
.prose .step b { display: none; }
.chapter-link {
  border: 1px solid var(--stroke);
  border-radius: 999px;
  background: var(--lime);
  color: #162208;
  text-transform: none;
  letter-spacing: 0;
}
.chapter-link:hover { background: var(--lime-soft); }
.visual { top: 80px; }

/* Shared media system: every chapter uses the same in-reading-flow rules. */
.lesson,
.lesson:has(.full-media) {
  display: block;
}

.prose {
  width: 100%;
  max-width: none;
}

.prose .media {
  width: max-content;
  max-width: 100%;
  margin: 20px 0 30px;
  overflow: visible;
  background: transparent;
}

.prose .media button,
.media.toolbar-highlight button {
  display: block;
  width: auto;
  max-width: 100%;
  height: auto;
  padding: 0;
  position: static;
  overflow: visible;
  background: transparent;
}

.prose .media img,
.media.toolbar-highlight img {
  display: block;
  position: static;
  left: auto;
  top: auto;
  width: auto;
  max-width: min(100%, 920px);
  height: auto;
  max-height: none;
  object-fit: contain;
}

.prose .inline-screen-media,
.prose .video-media {
  width: min(100%, 920px);
}

.prose .inline-screen-media button {
  width: 100%;
}

.prose .inline-screen-media img {
  margin: 0 auto;
}

.prose .inline-toolbar-media {
  width: max-content;
  max-width: min(100%, 520px);
}

.prose .inline-toolbar-media img {
  max-width: min(100%, 520px);
}

.prose .inline-icon-media,
.media.toolbar-scale {
  width: max-content;
  max-width: 120px;
  border: 0;
}

.prose .inline-icon-media button,
.media.toolbar-scale button {
  padding: 8px;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.prose .inline-icon-media img,
.media.toolbar-scale img {
  width: auto;
  max-width: 64px;
  max-height: 64px;
  margin: auto;
  object-fit: contain;
  image-rendering: auto;
}

.prose .media figcaption {
  max-width: 920px;
  padding: 10px 2px 0;
  text-transform: none;
}

.prose .media figcaption span {
  color: var(--category, var(--pink));
  white-space: nowrap;
}

.inline-tool-icon {
  display: inline-grid;
  place-items: center;
  width: 42px;
  height: 42px;
  margin: -10px 6px -12px 10px;
  padding: 3px;
  vertical-align: middle;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: #fff;
  cursor: zoom-in;
}

.inline-tool-icon img {
  display: block;
  width: 32px;
  height: 32px;
  object-fit: contain;
}

.video-media iframe {
  display: block;
  width: min(100%, 920px);
  aspect-ratio: 16/9;
  border: 0;
}

/* Toolbar catalog: compact icon field with one persistent description panel. */
.chapter.toolbar-icons .tool-catalog {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 340px);
  gap: 24px;
  align-items: start;
  margin-top: 24px;
}

.chapter.toolbar-icons .tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(72px, 1fr));
  gap: 8px;
}

.chapter.toolbar-icons .tool-tile {
  min-width: 0;
  min-height: 78px;
  padding: 8px 5px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255,255,255,.64);
  color: inherit;
  cursor: pointer;
}

.chapter.toolbar-icons .tool-tile:hover,
.chapter.toolbar-icons .tool-tile.active {
  border-color: var(--category, var(--pink));
  box-shadow: 0 0 0 2px color-mix(in srgb, var(--category, var(--pink)) 28%, transparent);
}

.chapter.toolbar-icons .tool-tile img {
  display: block;
  width: 38px;
  height: 38px;
  margin: 0 auto 5px;
  object-fit: contain;
}

.chapter.toolbar-icons .tool-tile span {
  display: block;
  overflow: hidden;
  color: inherit;
  font-size: 10px;
  font-weight: 700;
  line-height: 1.15;
  text-overflow: ellipsis;
}

.chapter.toolbar-icons .tool-detail {
  position: sticky;
  top: 90px;
  padding: 22px;
  border: 1px solid var(--line);
  border-left: 4px solid var(--category, var(--pink));
  border-radius: 10px;
  background: rgba(255,255,255,.82);
}

.chapter.toolbar-icons .tool-detail > img {
  display: block;
  width: 72px;
  height: 72px;
  margin-bottom: 14px;
  object-fit: contain;
}

.chapter.toolbar-icons .tool-detail h2 {
  margin: 4px 0 10px;
  padding: 0;
  border: 0;
  text-transform: none;
}

.chapter.toolbar-icons .tool-source {
  margin: 0;
  color: var(--muted);
  font: 11px/1.35 Arial, sans-serif;
  letter-spacing: .08em;
  text-transform: uppercase;
}

.chapter.toolbar-icons .tool-detail > p:not(.tool-source) {
  margin: 0 0 16px;
  font: 16px/1.55 Georgia, serif;
}

.chapter.toolbar-icons .tool-detail dl,
.chapter.toolbar-icons .tool-detail dl div {
  margin: 0;
}

.chapter.toolbar-icons .tool-detail dl div {
  padding: 10px 0;
  border-top: 1px solid var(--line);
}

.chapter.toolbar-icons .tool-detail dt {
  color: var(--muted);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
}

.chapter.toolbar-icons .tool-detail dd {
  margin: 3px 0 0;
  font-size: 14px;
}

@media (max-width: 850px) {
  .chapter.toolbar-icons .tool-catalog { grid-template-columns: 1fr; }
  .chapter.toolbar-icons .tool-detail { position: static; grid-row: 1; }
}
.media, .placeholder, .icon {
  color: var(--text);
  border-color: var(--stroke);
  border-radius: 12px;
  background: var(--panel-deep);
}
.media button { background: var(--panel-deep); }
.media figcaption { color: var(--text-muted); text-transform: none; }
.placeholder { background: var(--panel-deep); }
.placeholder span { background: var(--category); color: #0c1117; }
.placeholder strong, .placeholder p { background: transparent; color: var(--text-soft); }
.icon { background: var(--panel-deep); }
.icon p { color: var(--text-muted); }
.index .prose > h2 {
  color: var(--text) !important;
  background: var(--panel-deep) !important;
  border: 1px solid var(--stroke) !important;
  border-left: 4px solid var(--category) !important;
  border-radius: 8px;
}
.index .chapter-link, .index .chapter-link[data-category] {
  color: var(--text) !important;
  background: var(--panel-deep) !important;
  border-color: var(--stroke);
  border-radius: 9px;
  text-transform: none;
  letter-spacing: 0;
}
.index .chapter-link:hover { border-color: var(--lime); background: var(--panel-soft) !important; }
dialog { background: rgba(3,6,10,.94); }
dialog button { border-radius: 999px; background: var(--panel); border-color: var(--stroke); }

@media (max-width: 1000px) {
  .topbar { height: 60px; padding: 0 8px; }
  .brand { height: 55px; min-width: 185px; }
  .rail { top: 60px; }
  .workspace { margin-left: 0; padding-top: 60px; }
}
@media (max-width: 650px) {
  .brand { min-width: 52px; }
  .brand b { display: none; }
  .search { margin-right: 4px; }
  .workspace-head { min-height: 0; padding: 34px 18px 22px; }
  .workspace-head h1 { font-size: 43px; }
  .reader { margin: 0 10px 28px; }
  .chapter { padding: 26px 18px 34px; border: 1px solid var(--stroke); border-top: 3px solid var(--category); border-radius: 13px; }
  .rail { width: min(326px, 90vw); }
}

/* Permanent media invariant: chapter screenshots must never be cropped. */
.chapter .media,
.chapter .media button {
  height: auto !important;
  max-height: none !important;
  overflow: visible !important;
  clip: auto !important;
  clip-path: none !important;
}
.chapter .media img {
  position: static !important;
  inset: auto !important;
  width: auto !important;
  max-width: 100% !important;
  height: auto !important;
  max-height: none !important;
  object-fit: contain !important;
  object-position: center !important;
  transform: none !important;
  clip: auto !important;
  clip-path: none !important;
}