:root {
  color-scheme: dark;
  --bg: #080e1e;
  --surface: #101a30;
  --panel: #101d35;
  --panel2: #142847;
  --text: #edf4ff;
  --muted: #9baec8;
  --border: #223452;
  --blue: #39c9ff;
  --teal: #37e6c0;
  --purple: #ab91f9;
  --orange: #ffcf5a;
  --accent: #3bcaff;
  --shadow: 0 20px 38px #03081666;
  font-family:
    system-ui,
    -apple-system,
    'Segoe UI',
    sans-serif;
  font-synthesis: none;
  background: var(--bg);
  color: var(--text);
}
* {
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
}
body {
  margin: 0;
  background:
    radial-gradient(ellipse at 80% 12%, #152341 0%, transparent 32%), var(--bg);
  min-height: 100vh;
}
button,
input,
select {
  font: inherit;
}
button {
  cursor: pointer;
}
button:disabled {
  opacity: 0.46;
  cursor: not-allowed;
}
button:focus-visible,
a:focus-visible,
input:focus-visible {
  outline: 3px solid var(--teal);
  outline-offset: 3px;
}
a {
  color: inherit;
}
h1,
h2,
h3,
p {
  margin-top: 0;
}
button {
  touch-action: manipulation;
}
.layout {
  display: grid;
  grid-template-columns: 232px minmax(0, 1fr);
  min-height: 100vh;
}
.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  background: #091428;
  border-right: 1px solid #203457;
  padding: 25px 16px;
  display: flex;
  flex-direction: column;
}
.brand {
  display: flex;
  align-items: center;
  gap: 11px;
  color: var(--text);
  text-decoration: none;
  font-size: 20px;
  font-weight: 850;
  letter-spacing: -0.5px;
  margin-bottom: 48px;
}
.brand small {
  display: block;
  color: #83cde4;
  font-size: 9px;
  letter-spacing: 1.5px;
  margin-top: 1px;
}
.brand-symbol {
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 13px;
  background: linear-gradient(140deg, #2076e8, #39c9ff);
  box-shadow: 0 0 17px #218cec55;
  color: #fff;
  font-size: 22px;
  font-weight: 900;
}
.nav-label,
.kicker {
  font-size: 12px;
  font-weight: 850;
  letter-spacing: 1.65px;
  color: var(--blue);
}
.nav-label {
  padding: 0 12px 17px;
  font-size: 10px;
}
.nav-link {
  display: flex;
  align-items: center;
  gap: 15px;
  width: 100%;
  padding: 13px;
  margin: 3px 0;
  background: none;
  border: 1px solid transparent;
  color: #a8bbd4;
  border-radius: 13px;
  text-align: left;
  font-size: 14px;
  font-weight: 650;
}
.nav-link.active,
.nav-link:hover {
  background: #183958;
  border-color: #285e80;
  color: #fff;
}
.nav-link .nav-icon {
  width: 25px;
  text-align: center;
  font-size: 22px;
  color: var(--blue);
}
.sidebar-footer {
  margin-top: auto;
  color: #7890ad;
  font-size: 11px;
  line-height: 1.7;
}
.main-layout {
  min-width: 0;
}
.top {
  position: sticky;
  top: 0;
  z-index: 30;
  height: 76px;
  background: #080e1ff7;
  border-bottom: 1px solid #1b2948;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 30px;
  backdrop-filter: blur(15px);
}
.mobile-brand {
  display: none;
  color: var(--text);
  text-decoration: none;
  font-size: 19px;
  align-items: center;
  gap: 10px;
}
.top-right {
  display: flex;
  align-items: center;
  gap: 18px;
  margin-left: auto;
}
.top-label {
  font-size: 11px;
  color: #a6b8d4;
  letter-spacing: 0.9px;
  font-weight: 800;
}
.top-avatar {
  border: 1px solid #286995;
  color: #54d3ff;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: #163251;
  box-shadow: 0 0 22px #2d82bb44;
  font-size: 21px;
}
.stat-strip {
  max-width: 1130px;
  margin: 16px auto 0;
  padding: 9px 15px;
  display: flex;
  gap: 9px;
  flex-wrap: wrap;
  border: 1px solid #1f3155;
  border-radius: 26px;
  background: #0e182d;
  width: calc(100% - 60px);
}
.stat-strip > span {
  padding: 8px 14px;
  color: #8ea3c2;
  border: 1px solid #1c2b4a;
  border-radius: 22px;
  background: #0b1426;
  font-size: 10px;
  letter-spacing: 0.8px;
  font-weight: 850;
  white-space: nowrap;
}
.stat-strip strong {
  font-size: 18px;
  color: var(--blue);
  margin-right: 5px;
}
.stat-strip > span:nth-child(2) strong {
  color: var(--teal);
}
.stat-strip > span:nth-child(3) strong {
  color: var(--purple);
}
.stat-strip > span:nth-child(4) strong {
  color: var(--orange);
}
.stat-device {
  align-self: center;
  margin-left: auto;
  padding: 0 6px;
  color: #8ea3c2;
  font-size: 10px;
  font-style: normal;
  font-weight: 850;
  letter-spacing: 0.8px;
  text-transform: uppercase;
}
.container {
  width: min(100%, 1090px);
  min-height: calc(100vh - 200px);
  margin: auto;
  padding: 26px 30px 90px;
}
.footer {
  color: #7891aa;
  text-align: center;
  font-size: 11px;
  padding: 25px;
}
.mobile-nav {
  display: none;
}
.hero {
  position: relative;
  overflow: hidden;
  min-height: 350px;
  border-radius: 29px;
  background:
    radial-gradient(ellipse at 76% 28%, #214d70 0%, transparent 50%),
    linear-gradient(142deg, #162847, #0e152c 85%);
  border: 1px solid #273e69;
  box-shadow: var(--shadow);
  padding: 33px 43px;
  display: flex;
  align-items: flex-end;
}
.hero:before {
  content: '';
  position: absolute;
  inset: 0;
  background-image: linear-gradient(
    120deg,
    transparent 45%,
    #306f9519 68%,
    transparent 84%
  );
  pointer-events: none;
}
.hero-content {
  position: relative;
  z-index: 2;
  width: 100%;
}
.hero h1 {
  font-size: clamp(36px, 4.3vw, 63px);
  letter-spacing: -2px;
  line-height: 1.13;
  margin: 17px 0 14px;
  font-weight: 900;
}
.hero h1 em {
  font-style: normal;
  color: var(--blue);
}
.hero-content > strong {
  font-size: 17px;
  display: block;
  margin-bottom: 10px;
}
.hero-content p {
  font-size: 15px;
  line-height: 1.7;
  color: var(--muted);
  max-width: 520px;
  margin: 0;
}
.hero-art {
  pointer-events: none;
  position: absolute;
  right: 8%;
  top: 25px;
  width: 270px;
  height: 245px;
  opacity: 0.89;
}
.orb {
  position: absolute;
  inset: 17px 42px 30px;
  border-radius: 100%;
  display: grid;
  place-items: center;
  background: radial-gradient(
    circle at 35% 25%,
    #c0f7ff,
    #38bcf6 27%,
    #1b4c91 60%,
    #091429 85%
  );
  border: 1px solid #6eeaff;
  box-shadow:
    0 0 70px #49bbfb86,
    inset 0 0 26px #b4f7ffaa;
}
.orb > span:first-child {
  position: absolute;
  top: 5%;
  left: 20%;
  font-size: 34px;
  opacity: 0.55;
}
.orb-mark {
  font-size: 95px;
  font-weight: 900;
  text-shadow: 0 0 20px #ffffffdd;
  color: #dbf8ff;
}
.orbit {
  position: absolute;
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border: 1px solid #3a9cccaa;
  background: #15456c;
  border-radius: 100%;
  font-size: 25px;
  box-shadow: 0 0 20px #2a9fd777;
}
.orbit-a {
  top: 28px;
  left: 6px;
}
.orbit-b {
  top: 62px;
  right: 3px;
}
.orbit-c {
  bottom: 17px;
  left: 12px;
}
.heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 15px;
  margin: 37px 0 18px;
}
.heading h2 {
  margin: 0;
  font-weight: 900;
  font-size: 22px;
  letter-spacing: -0.5px;
}
.heading p,
.section-intro p {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
  margin: 4px 0 0;
}
.link {
  border: 0;
  background: none;
  color: var(--blue);
  font-weight: 800;
  white-space: nowrap;
}
.quick-filter {
  border-radius: 28px;
  border: 1px solid #223a5f;
  background: #0b1429;
  display: flex;
  gap: 3px;
  padding: 5px;
  margin: 0 0 19px;
  overflow-x: auto;
  scrollbar-width: none;
}
.filter-pill {
  min-width: 0;
  flex: 1;
  background: transparent;
  border: 0;
  border-radius: 23px;
  color: #a4b3d0;
  padding: 11px 14px;
  font-weight: 700;
  white-space: nowrap;
}
.filter-pill.selected {
  background: linear-gradient(100deg, #266af4, #38c9f9);
  color: white;
  box-shadow: 0 3px 20px #278cff66;
}
.quick-cards {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 15px;
}
.quick-card {
  text-align: left;
  min-height: 260px;
  border: 1px solid #29456a;
  border-radius: 26px;
  padding: 24px;
  display: flex;
  align-items: flex-start;
  flex-direction: column;
  gap: 13px;
  color: var(--text);
  box-shadow: var(--shadow);
  transition: transform 0.15s ease;
}
.quick-card:hover {
  transform: translateY(-2px);
}
.quick-cards > .quick-card[hidden] {
  display: none;
}
.quick-cards:has(> .quick-card[hidden]) {
  grid-template-columns: 1fr;
}
.quick-cards:has(> .quick-card[hidden]) > .quick-card:not([hidden]) {
  min-height: 170px;
}
.quick-cards:has(> .quick-card[hidden]) > .quick-card:not([hidden]) p {
  max-width: 600px;
}
.quick-cards:has(> .quick-card[hidden])
  > .quick-card:not([hidden])
  .quick-icon {
  display: none;
}
.quick-cards:has(> .quick-card[hidden]) > .quick-card:not([hidden]) > div {
  margin-top: 0;
}
.quick-card strong {
  font-size: 25px;
  line-height: 1.2;
  letter-spacing: -0.8px;
}
.quick-card p {
  font-size: 13px;
  line-height: 1.7;
  color: #aabbd4;
  flex: 1;
  margin: 0;
}
.quick-card > div:last-child {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 15px;
  width: 100%;
  font-size: 12px;
  font-weight: 800;
  color: var(--blue);
  margin-top: 20px;
}
.quick-card .quick-icon {
  width: 65px;
  height: 65px;
  border-radius: 18px;
  display: grid;
  place-items: center;
  font-size: 30px;
  background: #2063a233;
  border: 1px solid #389de36b;
  color: var(--blue);
}
.quick-cards .quick-cards {
  width: 100%;
}
.quick-cards .quick-tables {
  background: linear-gradient(140deg, #123d39, #0a2331);
  border-color: #206a66;
}
.quick-cards .quick-tables .quick-icon {
  color: var(--teal);
  border-color: #238e7f;
  background: #2ab59a20;
}
.quick-cards .quick-tables > div:last-child {
  color: var(--teal);
}
.quick-cards .quick-practice {
  background: linear-gradient(140deg, #29204b, #14122f);
  border-color: #51457c;
}
.quick-cards .quick-practice .quick-icon {
  color: var(--purple);
  border-color: #755fb2;
  background: #6747b622;
}
.quick-cards .quick-practice > div:last-child {
  color: var(--purple);
}
.quick-cards .quick-cards {
  background: linear-gradient(140deg, #17385f, #0b192e);
}
.arrow-circle {
  display: grid;
  place-items: center;
  width: 37px;
  height: 37px;
  border-radius: 50%;
  border: 1px solid currentColor;
  font-size: 19px;
}
.topic-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.chip {
  border: 1px solid #294364;
  border-radius: 26px;
  padding: 10px 15px;
  background: #0f1a31;
  color: #dbe7f5;
  font-weight: 700;
  font-size: 13px;
  white-space: nowrap;
}
.chip:hover,
.chip.active {
  border-color: #2ea9e9;
  color: white;
  background: #144971;
}
.activity-list {
  border: 1px solid #172943;
  border-radius: 22px;
  overflow: hidden;
  background: #0c172c;
}
.activity-item {
  padding: 16px 20px;
  display: flex;
  align-items: center;
  gap: 13px;
  border-bottom: 1px solid #1b2944;
}
.activity-item:last-child {
  border: 0;
}
.activity-item > span {
  color: var(--blue);
  font-size: 21px;
  min-width: 24px;
}
.activity-item p {
  font-size: 13px;
  margin: 0;
  color: #d9e7f7;
  line-height: 1.6;
}
.activity-item small {
  display: block;
  color: var(--muted);
  font-size: 12px;
  margin-top: 3px;
}
.fine-print {
  margin-top: 20px;
  font-size: 12px;
  color: #8fa3bf;
  line-height: 1.65;
}
.empty {
  background: #101e32;
  color: #a3b6ce;
  padding: 25px;
  border-radius: 18px;
}
.hub-banner {
  border-radius: 28px;
  padding: 35px;
  background:
    radial-gradient(ellipse at 100% 110%, #18608755, transparent 65%),
    linear-gradient(140deg, #111c37, #11243c);
  border: 1px solid #2a4577;
}
.hub-banner.hub-tables {
  background:
    radial-gradient(ellipse at 90% 100%, #0c80634a, transparent 65%),
    linear-gradient(140deg, #131e35, #112f32);
}
.hub-banner.hub-practice {
  background:
    radial-gradient(ellipse at 95% 100%, #6e50ac66, transparent 65%),
    linear-gradient(140deg, #181b3a, #282044);
}
.hub-banner h1 {
  font-size: clamp(33px, 4.5vw, 52px);
  letter-spacing: -1.5px;
  margin: 15px 0 10px;
}
.hub-banner > p {
  max-width: 570px;
  color: #9fb0c9;
  line-height: 1.75;
  font-size: 15px;
}
.hub-progress {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 22px;
  max-width: 390px;
  border: 1px solid #2c6486;
  border-radius: 60px;
  background: #1c567333;
  padding: 13px;
  margin: 24px auto 0;
}
.hub-progress > strong {
  font-size: 25px;
  letter-spacing: -0.6px;
}
.hub-progress em {
  font-style: normal;
  color: #92abc8;
}
.hub-progress strong small {
  display: block;
  font-size: 10px;
  font-weight: 750;
  letter-spacing: 1.7px;
  color: #a4bcd3;
}
.progress-ring {
  --pct: 0%;
  width: 60px;
  height: 60px;
  display: inline-grid;
  place-items: center;
  background: conic-gradient(var(--blue) var(--pct), #2d3c57 0);
  border-radius: 50%;
  padding: 5px;
  flex-shrink: 0;
}
.progress-ring > span {
  background: #142138;
  width: 100%;
  height: 100%;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-size: 16px;
  font-weight: 850;
}
.hub-progress .progress-ring {
  width: 67px;
  height: 67px;
}
.btn-outline {
  background: #19324b;
  color: #bceaff;
  border: 1px solid #386c91;
  padding: 12px 20px;
  border-radius: 24px;
  font-weight: 800;
}
.btn-outline.reset {
  font-size: 11px;
  letter-spacing: 0.6px;
  background: #3b2c4e;
  border-color: #85578b;
  color: #f5b6d2;
}
.topic-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}
.topic-card {
  border: 1px solid #233653;
  border-radius: 22px;
  background: linear-gradient(130deg, #121c32, #0c162a);
  display: grid;
  grid-template-columns: 5px 1fr auto;
  gap: 10px;
  align-items: start;
  position: relative;
  text-align: left;
  min-height: 165px;
  color: var(--text);
  padding: 20px 18px 20px 14px;
}
.topic-card:not(:disabled):hover {
  border-color: #39caff;
}
.topic-card .topic-accent {
  width: 5px;
  min-height: 110px;
  border-radius: 7px;
  background: var(--blue);
  grid-row: 1 / span 2;
  grid-column: 1;
  box-shadow: 0 0 18px #38caff55;
}
.topic-card.not-ready {
  opacity: 0.65;
}
.topic-symbol {
  grid-column: 2;
  font-size: 26px;
}
.topic-body {
  grid-row: 2;
  grid-column: 2;
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.topic-body strong {
  font-size: 18px;
  font-weight: 900;
}
.topic-body small {
  font-size: 13px;
  color: var(--blue);
  font-weight: 750;
}
.topic-body .topic-sub {
  margin-top: 5px;
  font-size: 11px;
  line-height: 1.5;
  color: #91a4c1;
}
.topic-meter {
  grid-column: 3;
  grid-row: 1;
  display: flex;
  align-items: center;
  gap: 5px;
  flex-direction: column;
}
.topic-meter .progress-ring {
  width: 42px;
  height: 42px;
  padding: 3px;
}
.topic-meter .progress-ring > span {
  font-size: 11px;
}
.topic-meter small {
  font-size: 10px;
  color: #a8b7cc;
  font-weight: 750;
}
.topic-arrow {
  position: absolute;
  bottom: 17px;
  right: 20px;
  color: var(--blue);
  font-size: 22px;
}
.soon {
  font-size: 9px;
  letter-spacing: 1px;
  color: #d6ae73;
  background: #493b2c;
  border-radius: 13px;
  padding: 7px;
}
.section-intro {
  margin: 12px 0 25px;
}
.section-intro h1 {
  font-size: clamp(29px, 4vw, 47px);
  letter-spacing: -1.1px;
  margin: 11px 0 3px;
}
.section-title-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.crumb {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 4px 0 25px;
  color: #93b2ca;
  font-size: 12px;
}
.crumb button {
  border: 0;
  background: none;
  color: var(--blue);
  padding: 4px 0;
  font-weight: 750;
}
.deck-tools {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin: 14px 0 22px;
}
.study-card {
  border-radius: 24px;
  border: 1px solid #264366;
  background:
    radial-gradient(ellipse at 60% 45%, #194a6a57, transparent 70%),
    linear-gradient(#192545, #0f1931);
  box-shadow: var(--shadow);
  padding: 25px;
  min-height: 370px;
}
.study-card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: #92adc8;
  font-size: 12px;
  font-weight: 800;
}
.eyebrow-pill {
  letter-spacing: 1.2px;
  background: #0f435e;
  padding: 7px 13px;
  color: #60defb;
  border: 1px solid #2d7999;
  border-radius: 18px;
  font-size: 10px;
}
.flash-surface {
  border: 0;
  background: none;
  color: #eef7ff;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 18px;
  width: 100%;
  min-height: 245px;
  padding: 20px 10px;
  text-align: center;
  line-height: 1.65;
  font-weight: 700;
  font-size: clamp(18px, 3vw, 26px);
  white-space: pre-line;
}
.content-figure {
  display: block;
  width: 100%;
  max-width: 520px;
  height: auto;
  margin: 0 auto;
  padding: 12px;
  border-radius: 14px;
  background: #fff;
  color: #000;
}
.figure-zoom {
  display: block;
  width: 100%;
  max-width: 520px;
  margin: 0 auto;
  padding: 0;
  border: 0;
  background: none;
  color: inherit;
  cursor: zoom-in;
  text-align: center;
}
.figure-zoom:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 3px;
  border-radius: 14px;
}
.figure-hint {
  display: block;
  margin-top: 6px;
  color: #91a7c3;
  font-size: 11px;
  font-weight: 600;
}
.study-card > .figure-zoom {
  margin-top: 12px;
}
.practice-card > .figure-zoom {
  margin-bottom: 16px;
}
.zoom-locked,
.zoom-locked body {
  overflow: hidden;
}
.zoom-overlay {
  position: fixed;
  inset: 0;
  z-index: 60;
  display: flex;
  flex-direction: column;
  background: #03070f;
}
.zoom-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: max(12px, env(safe-area-inset-top)) 16px 12px;
  color: var(--muted);
  font-size: 13px;
}
.zoom-close {
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid #324b6e;
  border-radius: 999px;
  background: #121d35;
  color: var(--text);
  font: inherit;
  font-weight: 700;
}
.zoom-scroll {
  flex: 1;
  overflow: auto;
  display: flex;
  align-items: center;
  padding: 8px 8px max(16px, env(safe-area-inset-bottom));
  touch-action: pan-x pan-y pinch-zoom;
}
.zoom-image {
  display: block;
  width: 100%;
  max-width: 1100px;
  flex-shrink: 0;
  height: auto;
  margin: auto;
  padding: 12px;
  border-radius: 14px;
  background: #fff;
  color: #000;
  cursor: zoom-in;
}
.is-zoomed .zoom-scroll {
  align-items: flex-start;
}
.is-zoomed .zoom-image {
  width: 220%;
  max-width: none;
  cursor: zoom-out;
}
.flash-surface small {
  color: #91a7c3;
  font-size: 11px;
  font-weight: 600;
}
.flash-surface.is-answer {
  color: #e5f9fb;
}
.study-card-meta {
  display: flex;
  gap: 12px;
  justify-content: space-between;
  font-size: 11px;
  color: #a4b7d3;
  padding-top: 17px;
  border-top: 1px solid #294260;
}
.hint {
  color: #aee3d8;
  background: #18534e66;
  border-radius: 10px;
  padding: 10px 14px;
  line-height: 1.6;
  font-size: 12px;
}
.deck-actions {
  display: grid;
  grid-template-columns: 1fr 1.2fr 1fr;
  gap: 9px;
  position: sticky;
  bottom: 0;
  background: #0b1426eb;
  border: 1px solid #203b57;
  border-radius: 16px;
  padding: 8px;
  margin-top: 15px;
  z-index: 5;
  backdrop-filter: blur(8px);
}
.deck-actions button {
  color: #d6e6f9;
  background: #172942;
  border: 1px solid #294666;
  border-radius: 12px;
  font-weight: 750;
  font-size: 12px;
  padding: 12px 4px;
  min-height: 44px;
}
.deck-actions button.primary {
  background: #135574;
  color: #fff;
  border-color: #2b94b9;
}
.secondary-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin: 16px 0;
}
.secondary-actions button {
  background: #14233b;
  border: 1px solid #2b405b;
  border-radius: 22px;
  padding: 11px 16px;
  color: #c2d3e9;
  font-size: 12px;
  font-weight: 750;
}
.progress-line {
  height: 5px;
  background: #263a56;
  border-radius: 8px;
  overflow: hidden;
}
.progress-line span {
  height: 100%;
  display: block;
  background: var(--blue);
}
.accordion-list {
  display: grid;
  gap: 13px;
}
.accordion-card {
  display: flex;
  align-items: center;
  gap: 16px;
  text-align: left;
  width: 100%;
  padding: 19px;
  background: linear-gradient(135deg, #123438, #0c2530);
  border: 1px solid #1f6b72;
  border-radius: 18px;
  color: #e8faff;
}
.accordion-icon {
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border: 1px solid #34a49a;
  border-radius: 12px;
  color: var(--teal);
  font-size: 25px;
}
.accordion-card span:nth-child(2) {
  flex: 1;
}
.accordion-card strong {
  display: block;
  font-size: 15px;
  margin-bottom: 5px;
}
.accordion-card small {
  color: #a6c5c6;
  font-size: 12px;
}
.accordion-card > span:last-child {
  font-size: 22px;
  color: var(--teal);
}
.compare-stack {
  display: grid;
  gap: 16px;
}
.compare-feature {
  padding: 19px;
  border: 1px solid #285160;
  border-radius: 19px;
  background: linear-gradient(130deg, #112f34, #0b1d30);
}
.compare-feature h3 {
  font-size: 15px;
  color: #c8fcf3;
  margin-bottom: 13px;
}
.compare-item {
  padding: 12px 15px;
  border: 1px solid #284b59;
  border-radius: 12px;
  margin-top: 9px;
  background: #102833;
}
.compare-item small {
  display: block;
  color: var(--teal);
  font-size: 10px;
  font-weight: 850;
  letter-spacing: 0.8px;
  text-transform: uppercase;
}
.compare-item p {
  color: #dceaf0;
  font-size: 13px;
  line-height: 1.65;
  margin: 5px 0 0;
  white-space: pre-line;
}
.study-tip {
  border: 1px solid #6e599e;
  border-radius: 15px;
  padding: 19px;
  background: #24204a;
  color: #e5d6ff;
  margin-bottom: 18px;
}
.study-tip p {
  margin: 7px 0 0;
  font-size: 13px;
}
.set-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  margin: 7px 0 19px;
}
.set-bar .kicker {
  font-size: 11px;
}
.pill {
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.5px;
  padding: 7px 10px;
  background: #173454;
  color: #a6e6ff;
  border-radius: 18px;
  border: 1px solid #2c587c;
}
.practice-card {
  background: linear-gradient(155deg, #132944, #0e182d);
  padding: 25px;
  border: 1px solid #2c5275;
  border-radius: 24px;
}
.practice-card > h2 {
  font-size: clamp(18px, 2.9vw, 23px);
  line-height: 1.6;
  margin: 23px 0 19px;
  font-weight: 750;
  white-space: pre-line;
}
.question-choices {
  display: grid;
  gap: 11px;
}
.choice {
  text-align: left;
  border: 1px solid #315470;
  border-radius: 14px;
  background: #142b43;
  display: flex;
  align-items: flex-start;
  gap: 14px;
  color: #e4effb;
  padding: 14px 15px;
  min-height: 58px;
}
.choice > span {
  width: 29px;
  height: 29px;
  flex: 0 0 29px;
  display: grid;
  place-items: center;
  border: 1px solid #438bb8;
  background: #163858;
  color: var(--blue);
  border-radius: 8px;
  font-size: 13px;
  font-weight: 900;
}
.choice > strong {
  font-size: 13px;
  font-weight: 650;
  line-height: 1.6;
}
.choice.chosen {
  border-color: #61c4ff;
  background: #183e60;
}
.choice.correct {
  border-color: #40d8ac;
  background: #17473e;
}
.choice.wrong {
  border-color: #ee8c89;
  background: #5c293b;
}
.choice:disabled {
  opacity: 1;
}
.submit-answer {
  margin: 19px 0 0;
  padding: 13px 22px;
  background: linear-gradient(100deg, #287afa, #34c4ff);
  border: 0;
  border-radius: 12px;
  color: white;
  font-weight: 850;
  min-height: 46px;
}
.answer-box {
  margin-top: 20px;
  background: #132d3b;
  border: 1px solid #37a58a;
  border-left: 4px solid var(--teal);
  border-radius: 14px;
  padding: 20px;
}
.answer-box > strong {
  color: #6dffc9;
}
.answer-box p {
  font-size: 14px;
  line-height: 1.7;
  color: #e2f1ed;
  margin: 8px 0;
}
.answer-box .trap {
  color: #d0bb9e;
}
.answer-box small {
  color: #9badc4;
}
.metric-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}
.stat-panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  background: #102039;
  padding: 16px;
  border: 1px solid #2b4769;
  border-radius: 18px;
}
.stat-panel strong {
  font-size: 17px;
}
.stat-panel small {
  text-transform: capitalize;
  color: #a4bad4;
}
.panel {
  border: 1px solid #294465;
  background: linear-gradient(150deg, #131f37, #101a30);
  border-radius: 20px;
  padding: 24px;
}
.panel h2 {
  font-size: 21px;
}
.panel p {
  font-size: 14px;
  color: #b5c6dc;
  line-height: 1.8;
}
.setting-panel {
  margin-bottom: 17px;
}
.btn-danger {
  padding: 12px 18px;
  background: #4e2a40;
  border: 1px solid #98607e;
  border-radius: 12px;
  color: #ffe0ea;
  font-weight: 750;
}
.notice {
  border: 1px solid #497f9c;
  background: #142b43;
  color: #d5efff;
  border-radius: 12px;
  padding: 13px 17px;
  font-size: 13px;
  margin-bottom: 16px;
}
.notice[hidden],
#update-banner[hidden] {
  display: none;
}
#update-banner {
  border: 1px solid #38b993;
  border-radius: 10px;
  background: #17463c;
  color: #edfff8;
  padding: 12px;
  margin-bottom: 18px;
}
.small-button {
  border: 1px solid #64d6a6;
  color: #eafff4;
  padding: 6px 12px;
  border-radius: 8px;
  background: #255a4b;
}
.more-overlay {
  position: fixed;
  inset: 0;
  z-index: 45;
  background: #01050bac;
  display: flex;
  align-items: flex-end;
  justify-content: center;
}
.more-sheet {
  width: min(100%, 440px);
  max-height: 80vh;
  overflow-y: auto;
  background: #121d35;
  border: 1px solid #324b6e;
  border-radius: 24px 24px 0 0;
  padding: 19px 21px 35px;
  box-shadow: 0 0 40px #000b;
}
.sheet-handle {
  width: 50px;
  height: 5px;
  background: #36516e;
  border-radius: 6px;
  margin: 0 auto 20px;
}
.more-sheet .kicker {
  display: block;
  margin-bottom: 11px;
}
.more-option {
  display: flex;
  align-items: center;
  gap: 14px;
  text-align: left;
  width: 100%;
  padding: 13px;
  background: #172943;
  border: 1px solid #263d5d;
  border-radius: 12px;
  color: #e1efff;
  margin: 7px 0;
}
.more-option > span:first-child {
  font-size: 18px;
  width: 23px;
  text-align: center;
  color: var(--blue);
}
.more-option > strong {
  flex: 1;
  font-size: 14px;
}
.more-option > span:last-child {
  color: #7ecfff;
}
.close-menu {
  margin-top: 11px;
  color: var(--muted);
  background: none;
  border: 0;
  padding: 10px;
}
.mobile-tab {
  background: none;
}
.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;
}
kbd {
  background: #1f3855;
  padding: 1px 5px;
  border-radius: 5px;
  color: #e7f8ff;
}
@media (max-width: 1050px) {
  .quick-cards {
    grid-template-columns: 1fr;
  }
  .quick-card {
    min-height: 185px;
  }
  .hero-art {
    right: 3%;
    opacity: 0.53;
  }
  .topic-list {
    grid-template-columns: 1fr 1fr;
  }
}
@media (max-width: 870px) {
  .layout {
    display: block;
  }
  .sidebar {
    display: none;
  }
  .top {
    height: 72px;
    padding: 0 17px;
  }
  .mobile-brand {
    display: flex;
  }
  .top-label {
    font-size: 10px;
    letter-spacing: 0.2px;
  }
  .top-avatar {
    width: 38px;
    height: 38px;
  }
  .container {
    padding: 20px 15px 112px;
    min-height: calc(100vh - 210px);
  }
  .footer {
    padding-bottom: 115px;
  }
  .stat-strip {
    width: calc(100% - 30px);
    padding: 7px;
    gap: 5px;
    margin-top: 15px;
  }
  .stat-strip > span {
    padding: 7px 9px;
    font-size: 9px;
  }
  .stat-strip strong {
    font-size: 16px;
  }
  .hero {
    min-height: 330px;
    padding: 35px 25px;
    border-radius: 27px;
    align-items: flex-end;
  }
  .hero-content {
    padding-top: 85px;
  }
  .hero-art {
    width: 225px;
    height: 180px;
    right: 0%;
    top: -10px;
    opacity: 0.74;
  }
  .orb {
    inset: 8px 49px 6px;
  }
  .orb-mark {
    font-size: 66px;
  }
  .orbit {
    width: 32px;
    height: 32px;
    font-size: 19px;
  }
  /* Keep the lower-left orbit chip clear of the hero kicker text. */
  .orbit-c {
    left: auto;
    right: 4px;
    bottom: 4px;
  }
  .hero h1 {
    font-size: 41px;
    letter-spacing: -1.5px;
  }
  .hero-content > strong {
    font-size: 15px;
  }
  .hero p {
    font-size: 13px;
  }
  .quick-cards {
    grid-template-columns: 1fr;
  }
  .quick-card {
    padding: 26px;
    min-height: 230px;
  }
  .topic-list {
    grid-template-columns: 1fr;
  }
  .heading {
    margin: 33px 0 17px;
  }
  .heading h2 {
    font-size: 22px;
  }
  .hub-banner {
    padding: 28px 21px;
  }
  .hub-banner h1 {
    font-size: 40px;
  }
  .mobile-nav {
    position: fixed;
    z-index: 50;
    bottom: 0;
    left: 0;
    right: 0;
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    background: #070d1df5;
    border-top: 1px solid #243550;
    padding: 7px 8px calc(6px + env(safe-area-inset-bottom));
    backdrop-filter: blur(14px);
  }
  .mobile-tab {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2px;
    padding: 5px 0;
    color: #98a9c3;
    border: 1px solid transparent;
    border-radius: 13px;
    font-size: 11px;
    font-weight: 750;
    min-width: 0;
    min-height: 73px;
  }
  .mobile-tab.active {
    border-color: #29688a;
    background: #113147;
    color: #fff;
  }
  .tab-icon {
    font-size: 25px;
    height: 26px;
    line-height: 26px;
  }
  .mobile-tab.active .tab-icon {
    color: var(--blue);
  }
  .mobile-tab small {
    font-size: 10px;
    color: #aebacc;
    font-weight: 850;
  }
  .tab-progress {
    height: 5px;
    width: 65%;
    background: #2c3448;
    border-radius: 5px;
    margin-top: 4px;
    overflow: hidden;
  }
  .tab-progress i {
    display: block;
    height: 100%;
    background: var(--blue);
  }
  .more-overlay {
    bottom: 85px;
  }
  .more-sheet {
    width: 100%;
  }
  .deck-actions {
    position: sticky;
    bottom: 84px;
  }
  .topic-card {
    min-height: 147px;
  }
  .study-card {
    min-height: 300px;
    padding: 20px;
  }
  .flash-surface {
    min-height: 200px;
  }
  /* Leave room so the sticky action bar never hides the end of a card. */
  .study-card,
  .practice-card {
    margin-bottom: 12px;
    scroll-margin-bottom: 150px;
  }
  .stat-device {
    flex-basis: 100%;
    margin-left: 0;
    padding: 2px 6px 0;
    font-size: 9px;
  }
}
@media (max-width: 430px) {
  .stat-strip > span {
    font-size: 8px;
    padding: 5px 6px;
  }
  .stat-strip strong {
    font-size: 14px;
  }
  .hero h1 {
    font-size: 37px;
  }
  .hero-content p {
    font-size: 13px;
  }
  .filter-pill {
    font-size: 12px;
    padding: 11px 8px;
  }
  .quick-card strong {
    font-size: 26px;
  }
  .quick-card p {
    font-size: 13px;
  }
  .hub-progress {
    gap: 13px;
    padding: 10px;
  }
  .hub-progress > strong {
    font-size: 23px;
  }
  .hub-progress .progress-ring {
    width: 57px;
    height: 57px;
  }
  .hub-progress .btn-outline {
    padding: 9px 12px;
  }
  .deck-tools .chip {
    padding: 8px 11px;
  }
  .practice-card {
    padding: 19px;
  }
  .choice {
    padding: 12px;
  }
  .study-card {
    padding: 17px;
  }
}
@media (prefers-reduced-motion: reduce) {
  * {
    scroll-behavior: auto !important;
    transition: none !important;
    animation: none !important;
  }
}
.reduce-motion,
.reduce-motion * {
  scroll-behavior: auto !important;
  transition: none !important;
  animation: none !important;
}
/* Avoid long syllabus names extending the mobile viewport. */
.topic-chips .chip {
  max-width: 100%;
  white-space: normal;
  text-align: left;
  overflow-wrap: anywhere;
}

/* Batch 3: practice results, revision mode, continue, install, settings. */
[data-go]:focus-visible,
.choice:focus-visible,
.chip:focus-visible,
.toggle:focus-visible {
  outline: 3px solid var(--teal);
  outline-offset: 3px;
}
.score-line {
  margin: 4px 0 12px;
  color: var(--muted);
  font-size: 13px;
}
.revision-banner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 12px;
  margin: 10px 0 6px;
  padding: 12px 14px;
  border: 1px solid #6b55b8;
  border-radius: 14px;
  background: #241d46;
  color: #e5dcff;
}
.revision-banner strong {
  color: #fff;
}
.revision-banner span {
  flex: 1 1 200px;
  font-size: 13px;
  line-height: 1.5;
}
.answer-box.is-revision {
  border-color: #6b55b8;
}
.option-rationales {
  list-style: none;
  margin: 12px 0 8px;
  padding: 0;
  display: grid;
  gap: 6px;
}
.option-rationales li {
  display: flex;
  gap: 10px;
  padding: 8px 10px;
  border: 1px solid #263d5d;
  border-radius: 10px;
  font-size: 13px;
  line-height: 1.5;
}
.option-rationales li.is-correct {
  border-color: #2f9e80;
  background: #12332d;
}
.option-rationales b {
  color: var(--blue);
}
.results-panel {
  margin-top: 18px;
  padding: 22px 20px;
  border: 1px solid #3a4f86;
  border-radius: 20px;
  background: linear-gradient(160deg, #1a2550, #101d35);
  scroll-margin-top: 90px;
}
.results-panel h2 {
  margin: 6px 0 4px;
}
.results-panel h3 {
  margin: 18px 0 8px;
  font-size: 15px;
}
.results-score {
  margin: 0;
  font-size: 22px;
  font-weight: 850;
  color: #fff;
}
.results-note,
.results-perfect {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.6;
}
.results-missed {
  margin: 0 0 14px;
  padding-left: 20px;
  color: #dbe7f5;
  font-size: 13px;
  line-height: 1.6;
}
.continue-card {
  display: flex;
  align-items: center;
  gap: 14px;
  width: 100%;
  margin: 14px 0;
  padding: 16px;
  text-align: left;
  color: var(--text);
  background: linear-gradient(135deg, #123a52, #101d35);
  border: 1px solid #2b6f8f;
  border-radius: 18px;
}
.continue-icon {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: #1b5a7a;
  color: #bceaff;
  flex: none;
}
.continue-body {
  flex: 1;
  display: grid;
  gap: 3px;
  min-width: 0;
}
.continue-body small {
  color: var(--blue);
  font-size: 10px;
  font-weight: 850;
  letter-spacing: 0.9px;
}
.continue-body strong {
  overflow-wrap: anywhere;
}
.continue-body em {
  color: var(--muted);
  font-size: 12px;
  font-style: normal;
}
button.activity-item {
  width: 100%;
  text-align: left;
  color: inherit;
  font: inherit;
  cursor: pointer;
}
.activity-item small {
  display: block;
  margin-top: 2px;
  color: var(--muted);
  font-size: 11px;
}
.activity-go {
  margin-left: auto;
  color: #7ecfff;
}
.history-day {
  margin: 18px 0 8px;
  color: var(--muted);
  font-size: 12px;
  letter-spacing: 0.8px;
  text-transform: uppercase;
}
.install-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: 100%;
  margin: 16px 0 4px;
  padding: 13px;
  color: #d5efff;
  background: #122a44;
  border: 1px dashed #2b6f8f;
  border-radius: 14px;
  font-weight: 750;
}
.install-steps {
  margin: 10px 0;
  padding-left: 20px;
  line-height: 1.8;
}
.more-sheet h2 {
  margin: 0 0 8px;
}
.toggle-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}
.toggle-row small {
  display: block;
  margin-top: 3px;
  color: var(--muted);
}
.toggle {
  position: relative;
  flex: none;
  width: 52px;
  height: 30px;
  padding: 0;
  border: 1px solid #36516e;
  border-radius: 20px;
  background: #1a2a42;
}
.toggle span {
  position: absolute;
  top: 3px;
  left: 3px;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: #9baec8;
  transition: transform 0.15s ease;
}
.toggle.on {
  background: #135574;
  border-color: #2b94b9;
}
.toggle.on span {
  transform: translateX(22px);
  background: #fff;
}
.stat-panel em {
  display: block;
  margin-top: 4px;
  color: var(--muted);
  font-size: 11px;
  font-style: normal;
}

/* Batch 3.1: progress on desktop and the activity row background fix. */
button.activity-item {
  background: transparent;
  border: 0;
  border-bottom: 1px solid #1b2944;
  border-radius: 0;
}
button.activity-item:last-child {
  border-bottom: 0;
}
button.activity-item:hover {
  background: #12223d;
}
.nav-progress {
  margin-left: auto;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 4px;
  flex: none;
  width: 40px;
}
.nav-progress small {
  font-size: 11px;
  font-weight: 800;
  color: #c7d6ea;
}
.nav-bar {
  display: block;
  width: 40px;
  height: 4px;
  border-radius: 4px;
  background: #24324b;
  overflow: hidden;
}
.nav-bar i {
  display: block;
  height: 100%;
  background: var(--blue);
}
.nav-progress-tables .nav-bar i {
  background: var(--teal);
}
.nav-progress-practice .nav-bar i {
  background: var(--purple);
}
.quick-meter {
  display: flex;
  flex-direction: column;
  gap: 7px;
  width: 100%;
}
.quick-meter-label {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  font-size: 12px;
  font-weight: 700;
  color: #c7d6ea;
}
.quick-meter-bar {
  display: block;
  height: 6px;
  border-radius: 6px;
  background: #ffffff1a;
  overflow: hidden;
}
.quick-meter-bar i {
  display: block;
  height: 100%;
  border-radius: 6px;
  background: var(--blue);
}
.quick-tables .quick-meter-bar i {
  background: var(--teal);
}
.quick-practice .quick-meter-bar i {
  background: var(--purple);
}
.chip-progress {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: linear-gradient(90deg, #1d5a86 var(--pct), #0f1a31 var(--pct));
}
.chip-pct {
  font-size: 11px;
  font-weight: 800;
  color: var(--blue);
}