@import url("https://fonts.googleapis.com/css2?family=Manrope:wght@400;500;600;700;800&family=Unbounded:wght@600;700;800&display=swap");

:root {
  --ink: #101114;
  --paper: #f5f1e8;
  --paper-2: #fffdf7;
  --muted: #6e6c68;
  --line: #191a1e;
  --bio: #bafc4e;
  --chem: #ff5ac8;
  --phys: #57d8ff;
  --warning: #ffdc5e;
  --danger: #ff6b55;
  --accent: var(--bio);
  --shadow: 6px 6px 0 var(--ink);
  --radius: 18px;
  color-scheme: light;
  font-family: "Manrope", "Trebuchet MS", sans-serif;
  font-synthesis: none;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  min-width: 320px;
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 8%, color-mix(in srgb, var(--accent) 22%, transparent) 0 3px, transparent 4px),
    linear-gradient(90deg, rgba(16, 17, 20, 0.035) 1px, transparent 1px),
    linear-gradient(rgba(16, 17, 20, 0.035) 1px, transparent 1px),
    var(--paper);
  background-size: 31px 31px;
  min-height: 100vh;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  opacity: 0.22;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 160 160' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.75' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.12'/%3E%3C/svg%3E");
}

button,
input,
a {
  font: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button {
  color: inherit;
}

a {
  color: inherit;
}

img,
svg {
  display: block;
  max-width: 100%;
}

.skip-link {
  position: fixed;
  left: 14px;
  top: -80px;
  z-index: 1000;
  border: 2px solid var(--ink);
  padding: 10px 14px;
  background: var(--warning);
  font-weight: 800;
}

.skip-link:focus {
  top: 14px;
}

:focus-visible {
  outline: 4px solid var(--phys);
  outline-offset: 3px;
}

.boot-screen {
  min-height: 100vh;
  display: grid;
  place-content: center;
  justify-items: center;
  gap: 14px;
  font-weight: 800;
}

.boot-mark,
.brand-mark {
  display: grid;
  place-items: center;
  width: 46px;
  aspect-ratio: 1;
  border: 3px solid var(--ink);
  border-radius: 10px 18px 10px 18px;
  background: var(--accent);
  box-shadow: 4px 4px 0 var(--ink);
  font-family: "Unbounded", sans-serif;
  font-weight: 800;
  transform: rotate(-3deg);
}

.shell {
  width: min(1480px, 100%);
  margin: 0 auto;
  padding: 0 24px 72px;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 30;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  margin: 0 -24px;
  padding: 16px 24px;
  border-bottom: 2px solid var(--ink);
  background: rgba(245, 241, 232, 0.94);
  backdrop-filter: blur(12px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 13px;
  min-width: max-content;
  text-decoration: none;
}

.brand-copy {
  display: grid;
  line-height: 1;
}

.brand-name {
  font-family: "Unbounded", sans-serif;
  font-size: clamp(0.9rem, 1.7vw, 1.08rem);
  font-weight: 800;
  letter-spacing: -0.04em;
}

.brand-tag {
  margin-top: 5px;
  color: var(--muted);
  font-size: 0.67rem;
  font-weight: 800;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.top-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.search-trigger,
.icon-button,
.profile-button,
.solid-button,
.outline-button,
.tiny-button {
  border: 2px solid var(--ink);
  border-radius: 12px;
  background: var(--paper-2);
  cursor: pointer;
  font-weight: 800;
  transition: transform 150ms ease, box-shadow 150ms ease, background 150ms ease;
}

.search-trigger:hover,
.icon-button:hover,
.profile-button:hover,
.outline-button:hover,
.tiny-button:hover {
  transform: translate(-2px, -2px);
  box-shadow: 3px 3px 0 var(--ink);
}

.search-trigger {
  min-width: min(31vw, 350px);
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 10px 12px;
  color: var(--muted);
  text-align: left;
}

kbd {
  border: 1px solid #bbb5aa;
  border-bottom-width: 2px;
  border-radius: 5px;
  padding: 1px 6px;
  background: #efebe2;
  color: var(--ink);
  font-size: 0.72rem;
}

.profile-button {
  display: flex;
  align-items: center;
  gap: 8px;
  min-height: 42px;
  padding: 6px 11px 6px 7px;
  text-decoration: none;
}

.profile-dot {
  display: grid;
  place-items: center;
  width: 28px;
  aspect-ratio: 1;
  border: 2px solid var(--ink);
  border-radius: 50%;
  background: var(--warning);
  font-size: 0.72rem;
}

.hero {
  position: relative;
  overflow: hidden;
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(280px, 0.7fr);
  align-items: end;
  gap: 38px;
  margin: 34px 0 24px;
  padding: clamp(28px, 5vw, 62px);
  border: 3px solid var(--ink);
  border-radius: 28px;
  background: var(--ink);
  color: #fffdf7;
  box-shadow: 9px 9px 0 var(--accent);
}

.hero::after {
  content: "";
  position: absolute;
  right: -80px;
  top: -130px;
  width: 390px;
  aspect-ratio: 1;
  border: 52px solid var(--accent);
  border-radius: 50%;
  opacity: 0.94;
}

.eyebrow,
.section-kicker,
.micro-label {
  margin: 0;
  color: inherit;
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border: 1px solid rgba(255, 255, 255, 0.4);
  border-radius: 999px;
  padding: 6px 10px;
}

.eyebrow::before {
  content: "";
  width: 7px;
  aspect-ratio: 1;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 16px var(--accent);
}

.hero h1 {
  max-width: 900px;
  margin: 24px 0 18px;
  font-family: "Unbounded", sans-serif;
  font-size: clamp(2.15rem, 6vw, 5.45rem);
  line-height: 0.96;
  letter-spacing: -0.075em;
}

.hero h1 span {
  position: relative;
  z-index: 1;
  color: var(--ink);
  white-space: nowrap;
}

.hero h1 span::before {
  content: "";
  position: absolute;
  z-index: -1;
  inset: 5% -2% -7% -3%;
  background: var(--accent);
  transform: rotate(-1deg) skewX(-7deg);
}

.hero-copy > p:not(.eyebrow) {
  max-width: 650px;
  margin: 0;
  color: #cccac4;
  font-size: clamp(0.98rem, 1.8vw, 1.17rem);
  line-height: 1.7;
}

.hero-stats {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 11px;
}

.hero-stat {
  min-height: 112px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  border: 2px solid #fffdf7;
  border-radius: 15px;
  padding: 15px;
  background: var(--ink);
}

.hero-stat strong {
  font-family: "Unbounded", sans-serif;
  font-size: clamp(1.25rem, 2vw, 1.75rem);
}

.hero-stat span {
  color: #bbb9b3;
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.subject-switcher {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin: 24px 0 18px;
}

.subject-button {
  position: relative;
  overflow: hidden;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 13px;
  min-height: 86px;
  border: 3px solid var(--ink);
  border-radius: 20px;
  padding: 15px 18px;
  background: var(--paper-2);
  cursor: pointer;
  text-align: left;
  transition: transform 160ms ease, box-shadow 160ms ease, background 160ms ease;
}

.subject-button::before {
  content: "";
  position: absolute;
  inset: auto 0 0;
  height: 7px;
  background: var(--subject-color);
  transform: scaleX(0.25);
  transform-origin: left;
  transition: transform 180ms ease;
}

.subject-button:hover,
.subject-button[aria-pressed="true"] {
  transform: translate(-3px, -3px);
  box-shadow: 6px 6px 0 var(--ink);
}

.subject-button[aria-pressed="true"] {
  background: var(--subject-color);
}

.subject-button:hover::before,
.subject-button[aria-pressed="true"]::before {
  transform: scaleX(1);
}

.subject-symbol {
  display: grid;
  place-items: center;
  width: 44px;
  aspect-ratio: 1;
  border: 2px solid var(--ink);
  border-radius: 50%;
  background: var(--subject-color);
  font-family: "Unbounded", sans-serif;
  font-size: 0.78rem;
}

.subject-title {
  display: grid;
  gap: 3px;
}

.subject-title strong {
  font-family: "Unbounded", sans-serif;
  font-size: clamp(0.88rem, 1.5vw, 1.02rem);
}

.subject-title small {
  color: var(--muted);
  font-size: 0.7rem;
  font-weight: 700;
}

.subject-progress {
  display: grid;
  justify-items: end;
  gap: 5px;
  font-size: 0.74rem;
  font-weight: 800;
}

.mini-meter {
  width: 56px;
  height: 6px;
  overflow: hidden;
  border: 1px solid var(--ink);
  border-radius: 999px;
  background: var(--paper);
}

.mini-meter span {
  display: block;
  width: var(--value);
  height: 100%;
  background: var(--ink);
}

.study-grid {
  display: grid;
  grid-template-columns: 270px minmax(0, 1fr) 300px;
  align-items: start;
  gap: 18px;
}

.topic-rail,
.side-stack {
  position: sticky;
  top: 88px;
}

.panel {
  border: 2px solid var(--ink);
  border-radius: var(--radius);
  background: var(--paper-2);
  box-shadow: 4px 4px 0 var(--ink);
}

.topic-rail {
  max-height: calc(100vh - 108px);
  overflow: auto;
  padding: 17px;
}

.rail-heading,
.side-heading,
.lesson-section-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.rail-heading h2,
.side-heading h3,
.lesson-section-heading h2 {
  margin: 0;
  font-family: "Unbounded", sans-serif;
  font-size: 0.92rem;
  letter-spacing: -0.04em;
}

.count-chip,
.spec-chip,
.tier-chip,
.source-chip {
  display: inline-flex;
  align-items: center;
  border: 1.5px solid var(--ink);
  border-radius: 999px;
  padding: 4px 8px;
  background: var(--paper);
  font-size: 0.65rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.topic-list,
.lesson-mini-list,
.knowledge-list,
.leader-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.topic-list {
  display: grid;
  gap: 9px;
  margin-top: 14px;
}

.topic-button {
  width: 100%;
  display: grid;
  grid-template-columns: 36px 1fr auto;
  align-items: center;
  gap: 9px;
  border: 0;
  border-radius: 12px;
  padding: 9px;
  background: transparent;
  cursor: pointer;
  text-align: left;
}

.topic-button:hover {
  background: color-mix(in srgb, var(--accent) 30%, transparent);
}

.topic-button[aria-current="true"] {
  background: var(--accent);
}

.topic-code {
  display: grid;
  place-items: center;
  width: 34px;
  aspect-ratio: 1;
  border: 1.5px solid var(--ink);
  border-radius: 9px;
  background: var(--paper-2);
  font-size: 0.68rem;
  font-weight: 800;
}

.topic-button strong {
  font-size: 0.78rem;
  line-height: 1.25;
}

.topic-button small {
  color: var(--muted);
  font-size: 0.65rem;
  font-weight: 800;
}

.lesson-mini-list {
  display: grid;
  gap: 5px;
  margin: 8px 0 5px 45px;
}

.lesson-mini-button {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 8px;
  border: 0;
  border-left: 2px solid #ded8cd;
  padding: 5px 7px 5px 10px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 0.69rem;
  font-weight: 700;
  text-align: left;
}

.lesson-mini-button:hover,
.lesson-mini-button[aria-current="true"] {
  border-left-color: var(--ink);
  color: var(--ink);
}

.mini-check {
  flex: 0 0 auto;
  width: 9px;
  aspect-ratio: 1;
  border: 1px solid currentColor;
  border-radius: 50%;
}

.lesson-mini-button.is-done .mini-check {
  background: var(--accent);
  box-shadow: inset 0 0 0 2px var(--paper-2);
}

.lesson-console {
  overflow: hidden;
}

.lesson-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(22px, 4vw, 42px);
  border-bottom: 2px solid var(--ink);
  background: var(--accent);
}

.lesson-hero::after {
  content: attr(data-index);
  position: absolute;
  right: -0.04em;
  bottom: -0.27em;
  color: rgba(16, 17, 20, 0.08);
  font-family: "Unbounded", sans-serif;
  font-size: clamp(8rem, 18vw, 16rem);
  font-weight: 800;
  line-height: 1;
}

.lesson-meta {
  position: relative;
  z-index: 1;
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
}

.tier-chip {
  background: var(--ink);
  color: #fff;
}

.lesson-hero h1 {
  position: relative;
  z-index: 1;
  max-width: 800px;
  margin: 17px 0 10px;
  font-family: "Unbounded", sans-serif;
  font-size: clamp(1.9rem, 5vw, 4rem);
  line-height: 1;
  letter-spacing: -0.065em;
}

.lesson-hero > p {
  position: relative;
  z-index: 1;
  max-width: 680px;
  margin: 0;
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.55;
}

.lesson-tabs {
  display: flex;
  gap: 3px;
  overflow-x: auto;
  padding: 12px 18px 0;
  background: #ece7dc;
}

.tab-button {
  min-width: max-content;
  border: 2px solid transparent;
  border-bottom: 0;
  border-radius: 11px 11px 0 0;
  padding: 10px 15px;
  background: transparent;
  cursor: pointer;
  font-size: 0.78rem;
  font-weight: 800;
}

.tab-button[aria-selected="true"] {
  border-color: var(--ink);
  background: var(--paper-2);
}

.lesson-body {
  padding: clamp(18px, 3vw, 32px);
}

.lesson-section-heading {
  margin-bottom: 14px;
}

.lesson-section-heading p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 0.76rem;
  font-weight: 700;
}

.knowledge-list {
  counter-reset: knowledge;
  display: grid;
  gap: 10px;
}

.knowledge-item {
  counter-increment: knowledge;
}

.knowledge-button {
  width: 100%;
  display: grid;
  grid-template-columns: 38px 1fr;
  align-items: start;
  gap: 12px;
  border: 2px solid #ddd7cb;
  border-radius: 14px;
  padding: 14px;
  background: #fffef9;
  cursor: pointer;
  text-align: left;
  transition: border-color 150ms ease, transform 150ms ease, background 150ms ease;
}

.knowledge-button:hover {
  border-color: var(--ink);
  transform: translateX(3px);
}

.knowledge-button::before {
  content: counter(knowledge, decimal-leading-zero);
  display: grid;
  place-items: center;
  width: 36px;
  aspect-ratio: 1;
  border: 1.5px solid var(--ink);
  border-radius: 10px;
  background: var(--paper);
  font-family: "Unbounded", sans-serif;
  font-size: 0.62rem;
}

.knowledge-button.is-mastered {
  border-color: var(--ink);
  background: color-mix(in srgb, var(--accent) 24%, #fffef9);
}

.knowledge-button.is-mastered::before {
  content: "✓";
  background: var(--accent);
  font-size: 0.9rem;
}

.knowledge-button span {
  font-size: 0.89rem;
  font-weight: 650;
  line-height: 1.55;
}

.spec-note {
  position: relative;
  margin-top: 18px;
  border: 2px dashed var(--ink);
  border-radius: 13px;
  padding: 17px 18px 17px 48px;
  background: var(--warning);
  transform: rotate(-0.35deg);
}

.spec-note::before {
  content: "“";
  position: absolute;
  left: 14px;
  top: 4px;
  font-family: Georgia, serif;
  font-size: 3rem;
  line-height: 1;
}

.spec-note p {
  margin: 4px 0 0;
  font-size: 0.86rem;
  font-weight: 800;
}

.source-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 18px;
}

.source-link {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  border-bottom: 2px solid var(--ink);
  padding: 3px 0;
  font-size: 0.72rem;
  font-weight: 800;
  text-decoration: none;
}

.source-link:hover {
  background: var(--accent);
}

.video-card {
  display: grid;
  grid-template-columns: minmax(230px, 0.95fr) minmax(220px, 1.05fr);
  overflow: hidden;
  border: 2px solid var(--ink);
  border-radius: 18px;
  background: var(--ink);
  color: #fff;
}

.video-thumb {
  position: relative;
  min-height: 260px;
  overflow: hidden;
  background: #23252a;
}

.video-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.72;
  transition: transform 260ms ease, opacity 260ms ease;
}

.video-card:hover .video-thumb img {
  transform: scale(1.035);
  opacity: 0.9;
}

.play-badge {
  position: absolute;
  inset: 50% auto auto 50%;
  display: grid;
  place-items: center;
  width: 68px;
  aspect-ratio: 1;
  border: 3px solid var(--ink);
  border-radius: 50%;
  background: var(--accent);
  color: var(--ink);
  font-size: 1.4rem;
  transform: translate(-50%, -50%);
  box-shadow: 5px 5px 0 #fff;
}

.video-copy {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  padding: clamp(22px, 4vw, 42px);
}

.video-copy h2 {
  margin: 10px 0 9px;
  font-family: "Unbounded", sans-serif;
  font-size: clamp(1.2rem, 2.4vw, 1.9rem);
  line-height: 1.16;
  letter-spacing: -0.045em;
}

.video-copy p {
  margin: 0 0 20px;
  color: #bbb;
  font-size: 0.83rem;
  font-weight: 700;
}

.solid-button,
.outline-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 9px 15px;
  text-decoration: none;
}

.solid-button {
  background: var(--accent);
  box-shadow: 4px 4px 0 #fff;
}

.solid-button:hover {
  transform: translate(2px, 2px);
  box-shadow: 1px 1px 0 #fff;
}

.outline-button {
  background: var(--paper-2);
}

.exam-stack {
  display: grid;
  gap: 16px;
}

.exam-card {
  overflow: hidden;
  border: 2px solid var(--ink);
  border-radius: 16px;
  background: #fffef9;
}

.exam-card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 14px;
  border-bottom: 2px solid var(--ink);
  background: var(--accent);
}

.exam-card-head strong {
  font-family: "Unbounded", sans-serif;
  font-size: 0.74rem;
}

.marks-badge {
  border: 1.5px solid var(--ink);
  border-radius: 999px;
  padding: 3px 8px;
  background: var(--paper-2);
  font-size: 0.68rem;
  font-weight: 800;
}

.exam-card-body {
  padding: 17px;
}

.exam-card-body > p {
  margin: 0;
  font-weight: 700;
  line-height: 1.55;
}

.question-diagram {
  width: min(100%, 500px);
  margin: 17px auto;
  border: 1.5px solid var(--ink);
  border-radius: 12px;
  padding: 12px;
  background: var(--paper);
}

.answer-panel {
  margin-top: 14px;
  border-top: 2px dashed #c9c2b6;
  padding-top: 14px;
}

.answer-panel[hidden] {
  display: none;
}

.answer-panel ol {
  margin: 8px 0 0;
  padding-left: 21px;
}

.answer-panel li {
  margin: 5px 0;
  font-size: 0.82rem;
  font-weight: 700;
}

.question-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 15px;
}

.tiny-button {
  padding: 7px 10px;
  font-size: 0.7rem;
}

.side-stack {
  display: grid;
  gap: 18px;
}

.focus-card {
  overflow: hidden;
  border: 2px solid var(--ink);
  border-radius: 18px;
  background: var(--ink);
  color: #fff;
  box-shadow: 4px 4px 0 var(--accent);
}

.focus-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 15px;
  border-bottom: 1px solid #3a3c41;
}

.live-dot {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 0.67rem;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.live-dot::before {
  content: "";
  width: 7px;
  aspect-ratio: 1;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 12px var(--accent);
}

.focus-body {
  padding: 22px;
  text-align: center;
}

.timer-ring {
  --timer: 100%;
  position: relative;
  display: grid;
  place-items: center;
  width: min(190px, 80%);
  aspect-ratio: 1;
  margin: 0 auto 18px;
  border-radius: 50%;
  background: conic-gradient(var(--accent) var(--timer), #34363b 0);
}

.timer-ring::before {
  content: "";
  position: absolute;
  inset: 9px;
  border-radius: 50%;
  background: var(--ink);
}

.timer-value {
  position: relative;
  font-family: "Unbounded", sans-serif;
  font-size: clamp(1.65rem, 3vw, 2.35rem);
  letter-spacing: -0.06em;
}

.focus-body p {
  margin: 0 0 15px;
  color: #aaa;
  font-size: 0.76rem;
  font-weight: 700;
}

.focus-actions {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 8px;
}

.focus-actions .solid-button {
  width: 100%;
}

.icon-button {
  display: grid;
  place-items: center;
  width: 44px;
  aspect-ratio: 1;
}

.progress-card,
.leader-card,
.nudge-card {
  padding: 17px;
}

.progress-overview {
  display: grid;
  grid-template-columns: 84px 1fr;
  align-items: center;
  gap: 13px;
  margin-top: 14px;
}

.progress-ring {
  --progress: 0%;
  position: relative;
  display: grid;
  place-items: center;
  width: 84px;
  aspect-ratio: 1;
  border-radius: 50%;
  background: conic-gradient(var(--accent) var(--progress), #ded9ce 0);
}

.progress-ring::before {
  content: "";
  position: absolute;
  inset: 8px;
  border: 1.5px solid var(--ink);
  border-radius: 50%;
  background: var(--paper-2);
}

.progress-ring strong {
  position: relative;
  font-family: "Unbounded", sans-serif;
  font-size: 0.88rem;
}

.progress-copy strong {
  display: block;
  font-family: "Unbounded", sans-serif;
  font-size: 0.83rem;
}

.progress-copy p {
  margin: 5px 0 0;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 700;
  line-height: 1.45;
}

.leader-list {
  display: grid;
  gap: 8px;
  margin-top: 13px;
}

.leader-row {
  display: grid;
  grid-template-columns: 24px 28px 1fr auto;
  align-items: center;
  gap: 8px;
  font-size: 0.72rem;
  font-weight: 800;
}

.leader-rank {
  color: var(--muted);
}

.leader-avatar {
  display: grid;
  place-items: center;
  width: 27px;
  aspect-ratio: 1;
  border: 1px solid var(--ink);
  border-radius: 8px;
  background: var(--warning);
  font-size: 0.62rem;
}

.leader-xp {
  color: var(--muted);
  font-size: 0.64rem;
}

.nudge-card {
  position: relative;
  overflow: hidden;
  background: var(--accent);
}

.nudge-card::after {
  content: "↗";
  position: absolute;
  right: -4px;
  bottom: -22px;
  font-family: "Unbounded", sans-serif;
  font-size: 7rem;
  opacity: 0.1;
}

.nudge-card p {
  position: relative;
  z-index: 1;
  margin: 8px 0 13px;
  font-size: 0.78rem;
  font-weight: 750;
  line-height: 1.45;
}

.command-overlay {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: grid;
  place-items: start center;
  padding: min(15vh, 130px) 18px 18px;
  background: rgba(16, 17, 20, 0.72);
  backdrop-filter: blur(8px);
}

.command-overlay[hidden] {
  display: none;
}

.command-panel {
  width: min(680px, 100%);
  overflow: hidden;
  border: 3px solid var(--ink);
  border-radius: 20px;
  background: var(--paper-2);
  box-shadow: 8px 8px 0 var(--accent);
}

.command-input-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px;
  border-bottom: 2px solid var(--ink);
}

.command-input {
  min-width: 0;
  flex: 1;
  border: 0;
  background: transparent;
  font-size: 1.05rem;
  font-weight: 750;
  outline: 0;
}

.command-results {
  max-height: 430px;
  overflow: auto;
  padding: 9px;
}

.search-result {
  width: 100%;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 11px;
  border: 0;
  border-radius: 11px;
  padding: 11px;
  background: transparent;
  cursor: pointer;
  text-align: left;
}

.search-result:hover {
  background: var(--accent);
}

.search-result strong {
  display: block;
  font-size: 0.82rem;
}

.search-result small {
  color: var(--muted);
  font-size: 0.68rem;
  font-weight: 700;
}

.empty-state {
  padding: 32px;
  color: var(--muted);
  font-weight: 700;
  text-align: center;
}

.toast-stack {
  position: fixed;
  right: 20px;
  bottom: 20px;
  z-index: 120;
  display: grid;
  gap: 8px;
  pointer-events: none;
}

.toast {
  max-width: 340px;
  border: 2px solid var(--ink);
  border-radius: 12px;
  padding: 11px 14px;
  background: var(--accent);
  box-shadow: 4px 4px 0 var(--ink);
  font-size: 0.78rem;
  font-weight: 800;
  animation: toast-in 220ms ease both;
}

.confetti {
  position: fixed;
  z-index: 150;
  width: 10px;
  height: 16px;
  background: var(--confetti);
  pointer-events: none;
  animation: confetti-pop 900ms cubic-bezier(.16,.84,.31,1) both;
}

.site-footer {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 24px;
  margin-top: 42px;
  border-top: 2px solid var(--ink);
  padding: 26px 0;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 700;
  line-height: 1.55;
}

.site-footer strong {
  color: var(--ink);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 13px;
}

.footer-links a {
  font-weight: 800;
}

/* Login */
.login-shell {
  min-height: 100vh;
  display: grid;
  grid-template-columns: minmax(320px, 1fr) minmax(380px, 0.8fr);
}

.login-art {
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: clamp(28px, 6vw, 76px);
  background: var(--ink);
  color: #fff;
}

.login-art::before,
.login-art::after {
  content: "";
  position: absolute;
  border: 4px solid var(--ink);
  border-radius: 50%;
  background: var(--phys);
}

.login-art::before {
  right: -130px;
  top: 10%;
  width: 390px;
  aspect-ratio: 1;
  box-shadow: -28px 34px 0 var(--chem);
}

.login-art::after {
  left: 12%;
  bottom: -140px;
  width: 280px;
  aspect-ratio: 1;
  background: var(--bio);
}

.login-brand {
  position: relative;
  z-index: 2;
  color: #fff;
}

.login-claim {
  position: relative;
  z-index: 2;
  max-width: 790px;
  margin: 60px 0;
}

.login-claim h1 {
  margin: 0;
  font-family: "Unbounded", sans-serif;
  font-size: clamp(2.5rem, 6vw, 6.4rem);
  line-height: 0.9;
  letter-spacing: -0.08em;
}

.login-claim h1 span {
  display: block;
  color: var(--bio);
}

.login-claim p {
  max-width: 550px;
  margin: 24px 0 0;
  color: #bdbdbd;
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.65;
}

.login-proof {
  position: relative;
  z-index: 2;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.proof-chip {
  border: 1px solid #777;
  border-radius: 999px;
  padding: 6px 10px;
  color: #ddd;
  font-size: 0.68rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.login-form-side {
  display: grid;
  place-items: center;
  padding: clamp(24px, 5vw, 72px);
  background: var(--paper);
}

.login-card {
  width: min(500px, 100%);
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  margin-bottom: 28px;
  font-size: 0.74rem;
  font-weight: 800;
  text-decoration: none;
}

.login-card h2 {
  margin: 0;
  font-family: "Unbounded", sans-serif;
  font-size: clamp(2rem, 5vw, 3.3rem);
  line-height: 1;
  letter-spacing: -0.065em;
}

.login-card > p {
  margin: 13px 0 23px;
  color: var(--muted);
  font-weight: 650;
  line-height: 1.55;
}

.auth-tabs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin-bottom: 19px;
}

.auth-tab {
  border: 2px solid var(--ink);
  border-radius: 11px;
  padding: 10px;
  background: var(--paper-2);
  cursor: pointer;
  font-weight: 800;
}

.auth-tab[aria-selected="true"] {
  background: var(--bio);
  box-shadow: 3px 3px 0 var(--ink);
}

.auth-form {
  display: grid;
  gap: 14px;
}

.field {
  display: grid;
  gap: 6px;
}

.field label {
  font-size: 0.74rem;
  font-weight: 800;
}

.field input {
  width: 100%;
  border: 2px solid var(--ink);
  border-radius: 12px;
  padding: 13px 14px;
  background: var(--paper-2);
  font-size: 1rem;
  font-weight: 700;
}

.field small {
  color: var(--muted);
  font-size: 0.65rem;
  font-weight: 650;
}

.password-wrap {
  position: relative;
}

.password-wrap input {
  padding-right: 70px;
}

.show-password {
  position: absolute;
  right: 8px;
  top: 50%;
  border: 0;
  padding: 6px;
  background: transparent;
  cursor: pointer;
  font-size: 0.68rem;
  font-weight: 800;
  transform: translateY(-50%);
}

.auth-submit {
  width: 100%;
  min-height: 52px;
  margin-top: 4px;
  border: 2px solid var(--ink);
  border-radius: 12px;
  background: var(--ink);
  color: #fff;
  cursor: pointer;
  font-family: "Unbounded", sans-serif;
  font-size: 0.78rem;
  font-weight: 800;
  box-shadow: 5px 5px 0 var(--bio);
}

.auth-submit:hover {
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0 var(--bio);
}

.auth-submit:disabled {
  cursor: wait;
  opacity: 0.65;
}

.auth-message {
  min-height: 22px;
  margin: 2px 0 0;
  color: var(--danger);
  font-size: 0.73rem;
  font-weight: 800;
}

.prototype-note {
  margin-top: 24px;
  border: 2px dashed var(--ink);
  border-radius: 12px;
  padding: 12px;
  background: var(--warning);
  font-size: 0.69rem;
  font-weight: 750;
  line-height: 1.45;
}

@keyframes toast-in {
  from { opacity: 0; transform: translateY(10px) rotate(1deg); }
  to { opacity: 1; transform: translateY(0) rotate(0); }
}

@keyframes confetti-pop {
  0% { opacity: 1; transform: translate(0, 0) rotate(0); }
  100% { opacity: 0; transform: translate(var(--x), var(--y)) rotate(var(--r)); }
}

@media (max-width: 1180px) {
  .study-grid {
    grid-template-columns: 240px minmax(0, 1fr);
  }

  .side-stack {
    position: static;
    grid-column: 1 / -1;
    grid-template-columns: repeat(3, 1fr);
  }

  .focus-card,
  .progress-card,
  .leader-card,
  .nudge-card {
    min-width: 0;
  }

  .nudge-card {
    display: none;
  }
}

@media (max-width: 860px) {
  .shell {
    padding-inline: 14px;
  }

  .topbar {
    margin-inline: -14px;
    padding-inline: 14px;
  }

  .brand-tag,
  .search-trigger span,
  .search-trigger kbd,
  .profile-button > span:last-child {
    display: none;
  }

  .search-trigger {
    min-width: 44px;
    width: 44px;
    justify-content: center;
    padding: 10px;
  }

  .search-trigger::before {
    content: "⌕";
    color: var(--ink);
    font-size: 1.2rem;
  }

  .hero {
    grid-template-columns: 1fr;
    padding: 28px;
  }

  .hero::after {
    right: -150px;
    top: auto;
    bottom: -180px;
  }

  .hero-stats {
    max-width: 480px;
  }

  .subject-switcher {
    grid-template-columns: 1fr;
  }

  .subject-button {
    min-height: 72px;
  }

  .study-grid {
    grid-template-columns: 1fr;
  }

  .topic-rail {
    position: static;
    max-height: none;
  }

  .topic-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .lesson-mini-list {
    display: none;
  }

  .side-stack {
    grid-template-columns: 1fr 1fr;
  }

  .leader-card {
    grid-column: 1 / -1;
  }

  .video-card {
    grid-template-columns: 1fr;
  }

  .video-thumb {
    min-height: 230px;
  }

  .login-shell {
    grid-template-columns: 1fr;
  }

  .login-art {
    min-height: 390px;
  }
}

@media (max-width: 560px) {
  .topbar {
    gap: 8px;
  }

  .brand-mark {
    width: 39px;
  }

  .hero {
    margin-top: 18px;
    padding: 23px;
    border-radius: 22px;
  }

  .hero h1 span {
    white-space: normal;
  }

  .hero-stats {
    grid-template-columns: 1fr 1fr;
  }

  .hero-stat {
    min-height: 92px;
  }

  .topic-list {
    grid-template-columns: 1fr;
  }

  .lesson-tabs {
    padding-inline: 8px;
  }

  .lesson-body {
    padding: 17px;
  }

  .knowledge-button {
    grid-template-columns: 32px 1fr;
    padding: 11px;
  }

  .knowledge-button::before {
    width: 31px;
  }

  .side-stack {
    grid-template-columns: 1fr;
  }

  .leader-card {
    grid-column: auto;
  }

  .site-footer {
    grid-template-columns: 1fr;
  }

  .login-art {
    min-height: 330px;
    padding: 24px;
  }

  .login-claim {
    margin: 42px 0 20px;
  }

  .login-claim p {
    display: none;
  }

  .login-form-side {
    padding: 30px 20px 50px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}