:root {
  --bg: #090b0a; --surface: #111411; --surface-2: #181c18; --ink: #f2f5ed;
  --muted: #9ca3b4; --line: #303646; --accent: #8fa6ff; --accent-ink: #0b1020;
  --danger: #ff6b62; --success: #8ce6b0; --warning: #f2c14e;
  --font-sans: "Segoe UI Variable", "Segoe UI", system-ui, sans-serif;
  --font-mono: "Cascadia Mono", "SFMono-Regular", Consolas, monospace;
  --text-xs: .72rem; --text-sm: .86rem; --text-md: 1rem; --text-lg: clamp(1.2rem, 2vw, 1.5rem);
  --text-xl: clamp(2.7rem, 10vw, 7.5rem); --radius-sm: 10px; --radius-lg: 28px;
  --dur-1: 140ms; --dur-2: 240ms; --dur-3: 420ms; --ease-out: cubic-bezier(.2,.9,.2,1);
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { min-height: 100%; overflow-x: clip; background: var(--bg); }
body {
  min-height: 100vh; min-height: 100dvh; margin: 0; overflow-x: clip; color: var(--ink); font-family: var(--font-sans);
  background: linear-gradient(rgba(143,166,255,.022) 1px,transparent 1px), linear-gradient(90deg,rgba(143,166,255,.022) 1px,transparent 1px), radial-gradient(circle at 50% 18%,rgba(143,166,255,.065),transparent 34rem), var(--bg);
  background-size: 28px 28px,28px 28px,auto,auto;
}
body.has-open-panel { overflow: hidden; }
button, select, input { font: inherit; }
button, select { color: inherit; }
button { -webkit-tap-highlight-color: transparent; }
.skip-nav { position: fixed; z-index: 100; left: 1rem; top: 1rem; padding: .7rem 1rem; color: var(--accent-ink); background: var(--accent); border-radius: var(--radius-sm); transform: translateY(-180%); }
.skip-nav:focus { transform: translateY(0); }
.app-shell { min-height: 100vh; display: grid; grid-template-rows: auto 1fr; }
.topbar { width: min(1180px,calc(100% - 32px)); margin: 0 auto; min-height: 76px; display: flex; align-items: center; justify-content: space-between; border-bottom: 1px solid var(--line); }
.brand { display: inline-flex; align-items: center; gap: .8rem; color: inherit; text-decoration: none; }
.brand-mark { display: grid; place-items: center; width: 34px; height: 34px; color: var(--accent-ink); background: var(--accent); border-radius: 50% 50% 50% 14%; font: 700 var(--text-xs)/1 var(--font-mono); letter-spacing: -.05em; }
.brand-name { font-weight: 720; letter-spacing: -.025em; }
.topbar-actions { display: flex; align-items: center; gap: .7rem; }
.app-nav { display: flex; gap: 4px; padding: 4px; border: 1px solid var(--line); border-radius: 999px; background: var(--surface); }
.nav-button { min-height: 34px; padding: 0 .75rem; border: 0; border-radius: 999px; color: var(--muted); background: transparent; font-size: var(--text-xs); cursor: pointer; }
.nav-button:hover,.nav-button.is-active { color: var(--accent-ink); background: var(--accent); }
.status-chip { display: inline-flex; align-items: center; gap: .55rem; min-height: 36px; padding: 0 .8rem; color: var(--muted); border: 1px solid var(--line); border-radius: 999px; font-size: var(--text-xs); }
.status-dot { width: 7px; height: 7px; flex: none; border-radius: 50%; background: var(--success); box-shadow: 0 0 0 4px rgba(140,230,176,.1); }
.is-offline .status-dot { background: var(--warning); box-shadow: 0 0 0 4px rgba(242,193,78,.1); }
.icon-button { min-width: 44px; min-height: 44px; border: 1px solid var(--line); border-radius: 50%; color: var(--ink); background: var(--surface); cursor: pointer; transition: border-color var(--dur-1),transform var(--dur-1); }
.icon-button:hover { border-color: var(--accent); transform: rotate(-4deg); }
.review-layout { width: min(980px,calc(100% - 32px)); margin: auto; padding: clamp(28px,6vh,72px) 0 32px; }
.session-rail { display: grid; grid-template-columns: auto minmax(100px,1fr) auto; align-items: end; gap: 1rem; margin-bottom: 16px; }
.session-rail strong { display: block; margin-top: .25rem; font: 650 var(--text-md)/1 var(--font-mono); }
.eyebrow { color: var(--muted); font: 600 var(--text-xs)/1.2 var(--font-mono); letter-spacing: .12em; text-transform: uppercase; }
.session-note { color: var(--muted); font-size: var(--text-sm); }
.progress-track { height: 2px; margin-bottom: .42rem; overflow: hidden; background: var(--line); }
.progress-track span { display: block; width: 25%; height: 100%; background: var(--accent); transition: width var(--dur-3) var(--ease-out); }
.study-card { position: relative; min-height: clamp(390px,55vh,590px); display: grid; grid-template-columns: auto 1fr; gap: clamp(24px,5vw,72px); overflow: hidden; padding: clamp(24px,5vw,56px); border: 1px solid var(--line); border-radius: var(--radius-lg); background: linear-gradient(145deg,rgba(255,255,255,.025),transparent 42%),var(--surface); box-shadow: 0 28px 80px rgba(0,0,0,.34); outline: none; }
.study-card.is-awaiting-tap { cursor: pointer; }
.study-card:focus-visible { box-shadow: 0 0 0 3px var(--bg),0 0 0 5px var(--accent),0 28px 80px rgba(0,0,0,.34); }
.card-index { color: var(--muted); font: 500 var(--text-xs)/1 var(--font-mono); }
.card-main { align-self: center; min-width: 0; }
.card-meta { display: flex; flex-wrap: wrap; gap: .5rem 1.2rem; color: var(--muted); font: 600 var(--text-xs)/1.2 var(--font-mono); letter-spacing: .08em; text-transform: uppercase; }
.card-main h1 { max-width: 12ch; margin: clamp(24px,6vh,64px) 0 20px; font-size: clamp(2.5rem,8vw,6.6rem); line-height: .96; letter-spacing: -.055em; overflow-wrap: anywhere; }
.has-long-prompt .card-main h1 { max-width: 19ch; font-size: clamp(2rem,5.5vw,4.6rem); line-height: 1; letter-spacing: -.045em; }
.has-very-long-prompt .card-main h1 { max-width: 30ch; font-size: clamp(1.55rem,3.8vw,3rem); line-height: 1.08; letter-spacing: -.03em; }
.prompt-hint { max-width: 48ch; margin: 0; color: var(--muted); font-size: var(--text-md); line-height: 1.55; }
.rule-summary { max-width: 66ch; margin: 0 0 1rem; color: #d7dceb; font-size: clamp(1rem,1.6vw,1.18rem); line-height: 1.65; }
mark { display: inline-block; padding: .02em .28em .08em; border-radius: .34em; color: #e5eaff; background: rgba(143,166,255,.16); font-weight: 750; }
.card-pulse { position: absolute; inset: 0 0 0 auto; width: 5px; background: var(--accent); opacity: .2; transform: scaleY(.18); transform-origin: bottom; transition: transform var(--dur-3) var(--ease-out),opacity var(--dur-2); }
.study-card.is-revealed .card-pulse { opacity: 1; transform: scaleY(1); }
.study-card.is-correct .card-pulse { background: var(--success); }
.study-card.is-wrong .card-pulse { background: var(--danger); }
.reveal-panel { margin-top: 2rem; animation: reveal-in var(--dur-3) var(--ease-out) both; }
.reveal-label { margin: 0 0 .8rem; color: var(--muted); font: 600 var(--text-xs)/1 var(--font-mono); letter-spacing: .08em; text-transform: uppercase; }
.options { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 10px; }
.option-button { min-height: 58px; padding: .9rem 1rem; border: 1px solid var(--line); border-radius: var(--radius-sm); text-align: left; color: var(--ink); background: var(--surface-2); cursor: pointer; transition: background var(--dur-1),border-color var(--dur-1),transform var(--dur-1); }
.option-button:hover { border-color: var(--accent); transform: translateY(-1px); }
.option-button[disabled] { cursor: default; transform: none; }
.option-button.is-correct { color: #dffbea; border-color: var(--success); background: rgba(140,230,176,.1); }
.option-button.is-wrong { color: #ffd8d5; border-color: var(--danger); background: rgba(255,107,98,.1); }
.rule-examples { display: grid; gap: 10px; }
.rule-formula { padding: 1rem 1.1rem; border: 1px solid rgba(143,166,255,.38); border-radius: var(--radius-sm); color: #e5eaff; background: linear-gradient(120deg,rgba(143,166,255,.14),rgba(143,166,255,.035)); font: 650 var(--text-md)/1.55 var(--font-mono); }
.rule-example { display: grid; gap: .35rem; margin: 0; padding: 1rem; border-left: 2px solid var(--accent); color: var(--ink); background: var(--surface-2); line-height: 1.5; }
.rule-example strong { font-size: var(--text-md); }
.rule-example span { color: var(--muted); font-size: var(--text-sm); }
.feedback { margin: 1rem 0 0; color: var(--muted); font-size: var(--text-sm); }
.feedback strong { color: var(--ink); }
.review-actions { grid-column: 1 / -1; display: flex; justify-content: flex-end; align-items: center; gap: 10px; align-self: end; padding-top: 8px; }
.button { min-height: 50px; padding: 0 1.15rem; border-radius: var(--radius-sm); border: 1px solid transparent; font-weight: 700; cursor: pointer; transition: transform var(--dur-1),filter var(--dur-1),border-color var(--dur-1); }
.button:hover { transform: translateY(-1px); filter: brightness(1.05); }
.button span { margin-left: .8rem; font: 500 var(--text-xs)/1 var(--font-mono); opacity: .62; }
.button-primary { margin-left: auto; color: var(--accent-ink); background: var(--accent); }
.button-secondary { min-height: 44px; color: var(--muted); border-color: var(--line); background: transparent; font-weight: 600; }
.review-actions .button-secondary { min-height: 40px; padding-inline: .65rem; border-color: transparent; font-weight: 550; }
.button:focus-visible,select:focus-visible,input:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
.session-footer { display: flex; flex-wrap: wrap; justify-content: center; gap: 1.2rem; margin-top: 22px; color: var(--muted); font-size: var(--text-xs); }
.session-footer strong { color: var(--ink); font-family: var(--font-mono); }
.scrim { position: fixed; z-index: 20; inset: 0; background: rgba(0,0,0,.66); backdrop-filter: blur(4px); }
.settings-panel { position: fixed; z-index: 30; inset: 0 0 0 auto; width: min(440px,100%); padding: 24px; overflow-y: auto; overscroll-behavior: contain; scrollbar-width: none; border-left: 1px solid var(--line); background: var(--surface); box-shadow: -24px 0 80px rgba(0,0,0,.42); transform: translateX(105%); transition: transform var(--dur-3) var(--ease-out); }
.settings-panel::-webkit-scrollbar,.study-card::-webkit-scrollbar { display: none; }
.settings-panel.is-open { transform: translateX(0); }
.settings-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 1rem; margin-bottom: 2rem; }
.settings-head h2 { margin: .45rem 0 0; font-size: var(--text-lg); }
.setting-row { display: flex; align-items: center; justify-content: space-between; gap: 1.2rem; padding: 1.1rem 0; border-top: 1px solid var(--line); }
.setting-row span { display: grid; gap: .35rem; }
.setting-row strong { font-size: var(--text-sm); }
.setting-row small { color: var(--muted); line-height: 1.4; }
.setting-row select { min-width: 76px; min-height: 44px; padding: 0 .7rem; border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--surface-2); }
.switch-row input { width: 48px; height: 26px; accent-color: var(--accent); }
.storage-note { display: flex; gap: .7rem; align-items: flex-start; margin: 1.5rem 0; padding: 1rem; color: var(--muted); border: 1px dashed var(--line); border-radius: var(--radius-sm); font-size: var(--text-xs); line-height: 1.45; }
.storage-note .status-dot { margin-top: .25rem; }
.settings-save { width: 100%; }
.sync-settings { display: grid; gap: .85rem; margin: 1.5rem 0; padding: 1rem 0; border-block: 1px solid var(--line); }
.sync-settings > div:first-child { display: flex; justify-content: space-between; gap: 1rem; }
.sync-settings small { color: var(--muted); line-height: 1.35; }
.sync-settings label { display: grid; gap: .4rem; color: var(--muted); font-size: var(--text-xs); font-weight: 700; }
.sync-settings input { min-height: 44px; padding: .7rem .8rem; border: 1px solid var(--line); border-radius: var(--radius-sm); color: var(--ink); background: var(--surface-2); }
.sync-actions { display: flex; flex-wrap: wrap; gap: .5rem; }
.sync-actions .button { flex: 1 1 8rem; margin: 0; }
.workspace-layout { width: min(1180px,calc(100% - 32px)); margin: 0 auto; padding: clamp(36px,7vh,80px) 0 96px; }
.workspace-head { display: flex; align-items: end; justify-content: space-between; gap: 2rem; padding-bottom: 2rem; border-bottom: 1px solid var(--line); }
.workspace-head h1 { margin: .4rem 0 .6rem; font-size: clamp(2.5rem,7vw,5.8rem); line-height: .9; letter-spacing: -.06em; }
.workspace-head p { max-width: 56ch; margin: 0; color: var(--muted); line-height: 1.5; }
.workspace-head > strong { color: var(--accent); font: 650 clamp(2rem,5vw,4rem)/1 var(--font-mono); }
.workspace-grid { display: grid; grid-template-columns: minmax(280px,.72fr) minmax(360px,1.28fr); gap: 18px; margin-top: 18px; align-items: start; }
.workspace-grid.is-rule-library { grid-template-columns: 1fr; }
.editor-card,.library-card { padding: clamp(20px,3vw,32px); border: 1px solid var(--line); border-radius: var(--radius-lg); background: var(--surface); }
.editor-card h2,.library-card h2 { margin: 0 0 .55rem; font-size: var(--text-lg); }
.editor-card > p { margin: 0 0 1.4rem; color: var(--muted); line-height: 1.5; }
.editor-card label,.search-field { display: grid; gap: .45rem; margin-bottom: 1rem; color: var(--muted); font-size: var(--text-xs); font-weight: 700; letter-spacing: .06em; text-transform: uppercase; }
.editor-card input,.editor-card textarea,.search-field input { width: 100%; min-height: 48px; padding: .8rem .9rem; border: 1px solid var(--line); border-radius: var(--radius-sm); color: var(--ink); background: var(--surface-2); resize: vertical; text-transform: none; letter-spacing: normal; font-weight: 500; }
.editor-card .button { width: 100%; margin: .4rem 0 0; }
.form-status { min-height: 1.4em; margin: .8rem 0 0 !important; font-size: var(--text-xs); }
.library-list { display: grid; max-height: min(64vh,660px); overflow: auto; }
.library-tabs { display: flex; gap: 5px; margin-bottom: 1rem; padding: 4px; border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--surface-2); }
.library-tab { flex: 1; min-height: 40px; border: 0; border-radius: 7px; color: var(--muted); background: transparent; cursor: pointer; font-weight: 700; }
.library-tab.is-active { color: var(--accent-ink); background: var(--accent); }
.library-hidden-toggle { width: 100%; min-height: 40px; margin: 0 0 1rem; border: 1px dashed var(--line); border-radius: var(--radius-sm); color: var(--muted); background: transparent; cursor: pointer; font-weight: 700; }
.library-hidden-toggle span { margin-left: .4rem; color: var(--ink); font-family: var(--font-mono); }
.library-hidden-toggle.is-active { color: var(--ink); border-style: solid; border-color: var(--accent); background: rgba(143,166,255,.08); }
.library-row { display: grid; grid-template-columns: minmax(0,.8fr) minmax(0,1fr) auto; align-items: center; gap: 1rem; padding: .9rem 0; border-top: 1px solid var(--line); font-size: var(--text-sm); line-height: 1.35; }
.library-row.is-hidden-content { opacity: .72; }
.library-primary { display: grid; gap: .3rem; min-width: 0; }
.library-primary > small { color: var(--muted); font-size: var(--text-xs); }
.library-row strong { overflow-wrap: anywhere; }
.library-row span { color: var(--muted); overflow-wrap: anywhere; }
.learning-stat { display: grid; justify-items: end; gap: .25rem; min-width: 92px; }
.learning-stat strong { color: var(--accent); font: 650 var(--text-xs)/1.2 var(--font-mono); text-transform: uppercase; }
.learning-stat small { color: var(--muted); white-space: nowrap; }
.library-tools { display: grid; justify-items: end; gap: .55rem; }
.visibility-button { min-height: 32px; padding: 0 .65rem; border: 1px solid var(--line); border-radius: 999px; color: var(--muted); background: transparent; cursor: pointer; font-size: var(--text-xs); font-weight: 650; }
.visibility-button:hover,.visibility-button:focus-visible { color: var(--ink); border-color: var(--accent); }
.rule-library-row { grid-template-columns: minmax(180px,.8fr) minmax(260px,1.2fr) auto; align-items: start; }
.rule-library-row code { color: var(--muted); font: 550 var(--text-xs)/1.5 var(--font-mono); }
.rule-library-row code mark { padding-inline: .16em; }
.rule-library-row p { margin: 0; color: var(--muted); line-height: 1.5; }
.inbox-row { grid-template-columns: 1fr auto; }
.inbox-row small { color: var(--muted); font-family: var(--font-mono); }
.empty-row { padding: 1.4rem 0; color: var(--muted); }
.sr-only { position: absolute !important; width: 1px !important; height: 1px !important; padding: 0 !important; margin: -1px !important; overflow: hidden !important; clip: rect(0,0,0,0) !important; white-space: nowrap !important; border: 0 !important; }
@keyframes reveal-in { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }
@media (max-width: 680px) {
  body[data-active-view="review"] { overflow: hidden; }
  body[data-active-view="review"] .app-shell { height: 100dvh; min-height: 0; }
  .topbar,.review-layout { width: min(100% - 20px,980px); }
  .app-nav { position: fixed; z-index: 18; inset: auto 10px max(8px,env(safe-area-inset-bottom)); justify-content: stretch; border-radius: 14px; box-shadow: 0 14px 40px rgba(0,0,0,.5); }
  .nav-button { flex: 1; min-height: 46px; }
  .topbar { min-height: 64px; } .status-chip { display: none; }
  .review-layout { height: calc(100dvh - 64px); min-height: 0; display: grid; grid-template-rows: auto minmax(0,1fr) auto; padding: 12px 0 calc(74px + env(safe-area-inset-bottom)); overflow: hidden; }
  .session-rail { grid-template-columns: auto 1fr; } .session-note { display: none; }
  .study-card { min-height: 0; height: 100%; grid-template-columns: 1fr; grid-template-rows: auto 1fr; gap: 10px; overflow-y: auto; overscroll-behavior: contain; scrollbar-width: none; padding: clamp(18px,5vw,22px); border-radius: 22px; }
  .card-pulse { inset: 0 0 auto; width: auto; height: 3px; transform: scaleX(.18); transform-origin: left; }
  .study-card.is-revealed .card-pulse { transform: scaleX(1); }
  .card-main h1 { max-width: 14ch; margin: clamp(20px,5vh,36px) 0 14px; font-size: clamp(2.15rem,11vw,4rem); line-height: 1; letter-spacing: -.045em; }
  .has-long-prompt .card-main h1 { max-width: 22ch; font-size: clamp(1.75rem,8vw,3rem); line-height: 1.04; }
  .has-very-long-prompt .card-main h1 { max-width: 30ch; font-size: clamp(1.35rem,6vw,2.2rem); line-height: 1.12; letter-spacing: -.025em; }
  .prompt-hint { font-size: .94rem; line-height: 1.45; }
  .rule-summary { margin-bottom: .8rem; font-size: .96rem; line-height: 1.55; }
  .reveal-panel { margin-top: 1.3rem; }
  .options { grid-template-columns: 1fr; }
  .review-actions { position: static; padding: 10px 0 0; background: transparent; }
  .button { min-height: 54px; } .button span { display: none; }
  .session-footer { justify-content: flex-start; gap: .8rem; margin-top: 10px; padding-inline: 4px; white-space: nowrap; overflow: hidden; }
  .workspace-layout { width: min(100% - 20px,980px); padding-top: 28px; }
  .workspace-head { align-items: flex-start; }
  .workspace-head > strong { font-size: 2rem; }
  .workspace-grid { grid-template-columns: 1fr; }
  .library-list { max-height: none; }
  .library-row { grid-template-columns: minmax(0,1fr) auto; gap: .45rem 1rem; }
  .library-row > span,.rule-library-row > p { grid-column: 1 / -1; }
  .library-tools { grid-column: 2; grid-row: 1; }
  .rule-library-row { grid-template-columns: minmax(0,1fr) auto; }
  .inbox-row { grid-template-columns: 1fr auto; }
}
@media (prefers-reduced-motion: reduce) { *,*::before,*::after { animation-duration: .001ms !important; animation-iteration-count: 1 !important; transition-duration: .001ms !important; scroll-behavior: auto !important; } }