:root {
  color-scheme: light;
  --ink: #20233c;
  --muted: #656a7e;
  --purple: #4f46e5;
  --purple-dark: #3f35c7;
  --lavender: #efedff;
  --green: #12775d;
  --line: #e4e7f0;
  --page: #fafbfe;
  font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 16px;
  scroll-behavior: smooth;
  scroll-padding-top: 105px;
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
body { margin: 0; color: var(--ink); background: var(--page); line-height: 1.6; -webkit-font-smoothing: antialiased; }
h1, h2, h3, p { margin: 0; }
h1, h2, h3 { text-wrap: balance; }
a { color: inherit; text-decoration: none; }
button, input { font: inherit; }
button, summary { cursor: pointer; }
button { color: inherit; }
button:disabled { cursor: default; }
button, a, summary, input { -webkit-tap-highlight-color: transparent; }
:focus-visible { outline: 3px solid #827aff; outline-offset: 5px; }
::selection { background: #ddd9ff; color: #2d246c; }
.container { width: min(1180px, calc(100% - 80px)); margin-inline: auto; }
.icon { width: 22px; height: 22px; display: inline-block; flex: none; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.skip-link { position: fixed; left: 12px; top: 10px; padding: 12px 18px; background: var(--ink); color: white; z-index: 100; transform: translateY(-170%); }
.skip-link:focus { transform: translateY(0); }
.site-header { position: sticky; top: 0; z-index: 20; background: #fafbfef2; border-bottom: 1px solid var(--line); backdrop-filter: blur(16px); }
.header-inner { min-height: 88px; display: flex; align-items: center; gap: 38px; }
.brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 720; font-size: 17px; letter-spacing: -.45px; white-space: nowrap; }
.brand-mark { display: grid; place-items: center; width: 36px; height: 38px; flex: none; border-radius: 12px 12px 12px 2px; background: var(--purple); color: white; font-size: 23px; font-weight: 700; }
.header-nav { display: flex; gap: 30px; margin-left: auto; font-size: 14px; color: var(--muted); }
.header-nav a:hover, .footer-links a:hover { color: var(--purple); }
.button { display: inline-flex; align-items: center; justify-content: center; gap: 20px; min-height: 52px; border: 1px solid transparent; border-radius: 10px; padding: 12px 22px; font-size: 15px; font-weight: 600; line-height: 1.4; transition: background .15s, border-color .15s, box-shadow .15s; }
.button > span { font-size: 20px; line-height: 1; }
.button-primary { color: white; background: var(--purple); box-shadow: 0 4px 8px #4f46e518; }
.button-primary:hover { background: var(--purple-dark); box-shadow: 0 6px 16px #4f46e525; }
.button-outline { background: white; border-color: var(--line); }
.button-outline:hover { border-color: #bbb5f6; background: #f4f3ff; }
.button-small { min-height: 44px; padding: 10px 18px; font-size: 14px; }
.button-text { background: transparent; padding-inline: 8px; color: var(--muted); }
.button-text:hover { color: var(--purple); }
.eyebrow { font-size: 11px; line-height: 1.7; letter-spacing: 1.65px; font-weight: 700; text-transform: uppercase; color: var(--purple); }
.eyebrow-line { display: inline-block; width: 20px; height: 2px; background: currentColor; vertical-align: middle; margin-right: 8px; }
.hero { display: grid; grid-template-columns: 1.06fr 1fr; gap: 54px; align-items: center; padding-block: 76px 52px; }
.hero-copy, .demo-wrap { min-width: 0; }
.hero h1 { font-size: clamp(37px, 4.1vw, 58px); font-weight: 730; letter-spacing: -2.6px; line-height: 1.1; margin-top: 23px; text-wrap: initial; }
.hero h1 > span { color: var(--purple); }
.hero-lead { margin-top: 25px; font-size: 18px; line-height: 1.65; color: var(--muted); max-width: 445px; }
.hero-actions { display: flex; align-items: center; flex-wrap: wrap; gap: 13px; margin-top: 29px; }
.hero-note { margin-top: 20px; font-size: 12px; color: var(--muted); }
.demo-wrap { position: relative; scroll-margin-top: 118px; }
.demo-caption { display: flex; gap: 7px; align-items: center; font-size: 11px; color: var(--muted); margin: 0 0 12px 5px; }
.status-dot { display: inline-block; flex: none; width: 6px; height: 6px; border-radius: 100%; background: #1c9674; }
.demo-window { background: white; border: 1px solid var(--line); border-radius: 18px; box-shadow: 0 20px 55px #332e7210, 0 3px 8px #332e7203; overflow: hidden; }
.demo-titlebar { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 18px 21px; border-bottom: 1px solid var(--line); font-size: 12px; }
.demo-subject { display: inline-flex; align-items: center; gap: 8px; font-weight: 600; }
.demo-subject .icon { width: 17px; height: 17px; color: var(--purple); }
.quiet-label { color: var(--muted); font-size: 11px; }
.demo-tabs { display: flex; gap: 5px; padding: 13px 15px 0; }
.demo-tab { flex: 1; border: 0; padding: 10px 3px; border-radius: 7px; background: transparent; color: var(--muted); font-size: 12px; line-height: 1.5; }
.demo-tab span { margin-right: 4px; font-size: 10px; }
.demo-tab[aria-selected="true"] { color: var(--purple); background: var(--lavender); font-weight: 600; }
.demo-panel { padding: 22px 20px 0; }
.panel-heading { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 14px; }
.panel-heading h2 { font-size: 14px; font-weight: 650; line-height: 1.4; text-wrap: initial; }
.small-badge { font-size: 10px; color: var(--muted); background: #f4f5f9; padding: 4px 7px; border-radius: 5px; white-space: nowrap; }
.example-board { position: relative; min-height: 225px; padding: 22px 12px 16px 42px; border: 1px solid #e8eaf2; border-radius: 9px; background: linear-gradient(#eaedf575 1px, transparent 1px), linear-gradient(90deg, #eaedf575 1px, transparent 1px); background-size: 21px 21px; text-align: center; }
.board-tools { position: absolute; top: 19px; left: 10px; display: flex; flex-direction: column; gap: 15px; font-size: 12px; color: #72778e; }
.board-tools .icon { width: 15px; height: 15px; color: var(--purple); }
.board-topic { font-size: 11px; color: var(--muted); }
.equation { font-family: Georgia, "Times New Roman", serif; font-size: 29px; color: var(--ink); margin-top: 17px; line-height: 1.3; white-space: nowrap; }
.board-solution { margin-top: 13px; color: var(--purple); font: 23px/1.5 Georgia, "Times New Roman", serif; }
.answer-circle { display: inline-block; font-size: 17px; border-bottom: 2px solid #aea7f5; padding: 2px 12px; }
.board-prompt { display: flex; align-items: center; justify-content: center; gap: 7px; margin-top: 35px; color: var(--purple); font-size: 12px; }
.pencil-line { width: 25px; height: 1px; background: #aba2f0; transform: rotate(-20deg); }
.demo-panel-footer { display: flex; align-items: center; justify-content: space-between; gap: 10px; min-height: 61px; font-size: 10px; color: var(--muted); }
.inline-action { display: inline-flex; align-items: center; gap: 9px; padding: 5px 0; border: 0; background: transparent; color: var(--purple); font-size: 13px; font-weight: 600; text-align: left; }
.inline-action:hover { text-decoration: underline; text-underline-offset: 4px; }
.demo-panel-footer .inline-action { font-size: 11px; min-height: 36px; }
.demo-status { display: flex; align-items: center; justify-content: space-between; gap: 10px; padding: 12px 16px; background: #fcfcfe; border-top: 1px solid var(--line); color: var(--muted); font-size: 10px; }
.demo-status > span:first-child { display: inline-flex; align-items: center; gap: 5px; }
.demo-under-caption { display: flex; align-items: center; justify-content: center; gap: 6px; color: var(--muted); font-size: 11px; margin-top: 16px; }
.demo-under-caption .icon { width: 13px; height: 13px; }
.practice-example { min-height: 225px; background: #f8f7ff; border-radius: 9px; padding: 24px 15px 18px; text-align: center; }
.practice-example > p:first-child { color: var(--muted); font-size: 12px; }
.answer-options { display: flex; gap: 8px; justify-content: center; margin-top: 23px; }
.answer-options button { flex: 1; min-height: 40px; border: 1px solid #dcd8f0; border-radius: 7px; background: white; font-size: 13px; padding: 8px 4px; }
.answer-options button:hover { border-color: var(--purple); }
.answer-options button.is-correct { border-color: #69af99; color: #096047; background: #e9f6f0; }
.answer-options button.is-incorrect { border-color: #cd796d; color: #a6372d; background: #fff1ee; }
.practice-feedback { min-height: 35px; margin-top: 15px; font-size: 11px; color: var(--muted); }
.practice-feedback.is-success { color: var(--green); }
.result-example { min-height: 225px; padding: 8px 4px; }
.result-item { display: flex; gap: 12px; align-items: flex-start; padding: 12px 0; }
.result-icon { flex: none; display: grid; place-items: center; width: 32px; height: 32px; border-radius: 9px; background: #eaf5ef; color: var(--green); font-size: 17px; }
.result-icon-purple { color: var(--purple); background: var(--lavender); }
.result-item strong { display: block; font-size: 12px; font-weight: 600; }
.result-item div > span { display: block; color: var(--muted); font-size: 11px; margin-top: 3px; }
.benefit-strip { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 12px; padding: 18px 0; border-block: 1px solid var(--line); }
.benefit-strip p { display: flex; align-items: center; justify-content: center; gap: 9px; min-width: 0; font-size: 12px; font-weight: 600; line-height: 1.35; }
.benefit-strip .icon { color: var(--purple); width: 19px; height: 19px; }
.section { padding-block: 105px; }
.section-intro { display: flex; justify-content: space-between; gap: 50px; align-items: flex-end; margin-bottom: 38px; }
.session-banner { display: grid; grid-template-columns: 1.05fr .95fr; align-items: stretch; margin-top: 28px; overflow: hidden; border-radius: 17px; background: #f0effb; }
.session-banner > img { display: block; width: 100%; height: 340px; object-fit: cover; object-position: center 52%; }
.session-banner-copy { display: flex; flex-direction: column; align-items: flex-start; justify-content: center; padding: 35px clamp(24px, 4vw, 55px); }
.session-banner-copy h2 { margin-top: 14px; font-size: clamp(23px, 2.8vw, 34px); line-height: 1.2; font-weight: 650; letter-spacing: -.8px; }
.session-banner-copy > p:last-child { margin-top: 13px; color: var(--muted); font-size: 14px; line-height: 1.75; }
.features-section { padding-top: 72px; }
.section h2, .method-section h2, .start-section h2 { font-size: clamp(29px, 3.1vw, 41px); line-height: 1.18; font-weight: 700; letter-spacing: -1.3px; margin-top: 15px; }
.section-intro > p { color: var(--muted); font-size: 14px; max-width: 320px; line-height: 1.8; padding-bottom: 3px; }
.feature-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; }
.feature-card { background: white; border: 1px solid var(--line); border-radius: 17px; overflow: hidden; padding: 28px; grid-column: auto; }
.feature-board, .feature-bank { padding: 33px 33px 0; }
.feature-board { background: #f0effc; border-color: #e7e3f8; }
.feature-bank { background: #edf6f2; border-color: #dcece4; }
.feature-number { color: var(--muted); letter-spacing: 1.2px; font-size: 10px; font-weight: 650; }
.feature-card h3 { font-size: 21px; line-height: 1.3; font-weight: 650; letter-spacing: -.45px; margin-top: 15px; }
.feature-board h3, .feature-bank h3 { font-size: 27px; letter-spacing: -.75px; }
.feature-card p { font-size: 14px; color: var(--muted); margin-top: 14px; line-height: 1.8; }
.feature-copy { max-width: 420px; }
.exam-illustration { display: flex; flex-direction: column; gap: 9px; min-height: 255px; margin-top: 30px; padding: 18px 20px 20px; background: white; border: 1px solid #dcece4; border-bottom: 0; border-radius: 12px 12px 0 0; }
.exam-toolbar { display: flex; align-items: center; justify-content: space-between; gap: 8px; color: var(--muted); font-size: 11px; }
.exam-toolbar > span:first-child { display: inline-flex; align-items: center; gap: 7px; color: var(--green); font-weight: 600; }
.exam-filter { padding: 4px 7px; border-radius: 5px; background: #f3f6f4; color: #64756b; font-size: 9px; }
.exam-task-list { display: flex; flex-direction: column; gap: 8px; margin-top: auto; }
.exam-task { display: flex; align-items: center; gap: 10px; min-width: 0; border: 1px solid var(--line); border-radius: 8px; padding: 9px 10px; }
.exam-task-number { display: grid; place-items: center; width: 30px; height: 30px; flex: none; border-radius: 7px; background: #f0effb; color: var(--purple); font-size: 11px; font-weight: 650; }
.exam-task > span:nth-child(2) { min-width: 0; flex: 1; }
.exam-task strong { display: block; overflow: hidden; color: var(--ink); font-size: 11px; font-weight: 600; text-overflow: ellipsis; white-space: nowrap; }
.exam-task small { display: block; margin-top: 3px; color: var(--muted); font-size: 9px; }
.exam-task-arrow { flex: none; color: #8ca091; font-size: 13px; }
.board-illustration { margin-top: 30px; padding: 22px 20px 24px; background: white; border: 1px solid #e4e1f3; border-bottom: 0; border-radius: 12px 12px 0 0; min-height: 255px; position: relative; }
.paper-label { display: flex; align-items: center; gap: 7px; font-size: 11px; color: var(--muted); }
.illustration-equation { font: 24px/1.4 Georgia, serif; margin: 22px 0 17px; }
.area-model { display: grid; grid-template-columns: 73px 39px; grid-template-rows: 60px 31px; gap: 2px; width: fit-content; text-align: center; font: 18px/1 Georgia, serif; }
.area-model span { display: grid; place-items: center; background: #ddd8ff; color: #504696; }
.area-model span:nth-child(2), .area-model span:nth-child(3) { background: #edeaff; }
.area-model span:last-child { background: #f3f1ff; }
.annotation { position: absolute; right: 20px; bottom: 43px; font-size: 12px; color: #6c608f; transform: rotate(-3deg); max-width: 52%; }
.feature-icon { display: grid; place-items: center; width: 40px; height: 40px; color: var(--purple); background: #f2f0ff; border-radius: 10px; }
.feature-card > .feature-number { display: block; margin-top: 13px; }
.topic-tags { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 23px; }
.topic-tags span { background: #f6f6fa; border-radius: 5px; color: var(--muted); font-size: 10px; padding: 5px 7px; }
.method-section { background: #efedf9; padding-block: 75px; }
.method-grid { display: grid; grid-template-columns: 1.1fr 1fr; align-items: center; gap: 100px; }
.method-section h2 { font-size: clamp(34px, 3.7vw, 47px); line-height: 1.17; }
.method-section h2 span { color: var(--purple); }
.section-text { margin: 22px 0 18px; max-width: 430px; color: var(--muted); line-height: 1.8; font-size: 15px; }
.learning-route { list-style: none; margin: 0; padding: 0; }
.learning-route li { position: relative; display: flex; align-items: flex-start; gap: 19px; padding-bottom: 32px; }
.learning-route li:not(:last-child)::after { content: ""; position: absolute; top: 39px; left: 19px; bottom: 0; width: 1px; background: #d6d0e9; }
.learning-route li:last-child { padding-bottom: 0; }
.route-marker { position: relative; z-index: 1; display: grid; place-items: center; width: 40px; height: 40px; background: #fbfaff; border: 1px solid #dfdaed; color: var(--purple); font-size: 11px; border-radius: 50%; flex: none; }
.route-marker-final { background: var(--purple); color: white; border: 0; }
.route-marker-final .icon { width: 19px; height: 19px; }
.learning-route h3 { font-size: 16px; font-weight: 600; margin-top: 2px; }
.learning-route p { color: var(--muted); font-size: 13px; margin-top: 4px; }
.people-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 42px; }
.people-grid article { border-top: 1px solid var(--line); padding-top: 25px; }
.person-label { font-size: 12px; color: var(--purple); }
.people-grid h3 { font-size: 20px; font-weight: 650; letter-spacing: -.4px; line-height: 1.4; margin: 13px 0 12px; }
.people-grid p { color: var(--muted); font-size: 14px; line-height: 1.8; }
.start-section { background: #23243e; border-radius: 22px; padding: 58px; display: grid; grid-template-columns: 1.1fr 1fr; gap: 65px; color: white; }
.start-heading .eyebrow { color: #b8b2ff; }
.start-heading > p:not(.eyebrow) { color: #c2c3d4; font-size: 14px; margin-top: 20px; }
.start-heading .button { margin-top: 25px; }
.start-steps { list-style: none; margin: 5px 0 0; padding: 0; }
.start-steps li { display: flex; gap: 19px; margin-top: 30px; }
.start-steps li:first-child { margin-top: 0; }
.start-steps li > span { display: grid; place-items: center; width: 30px; height: 30px; flex: none; border: 1px solid #565671; border-radius: 50%; font-size: 12px; color: #c0baff; }
.start-steps h3 { font-size: 16px; font-weight: 550; }
.start-steps p { margin-top: 7px; font-size: 13px; color: #c2c3d4; }
.faq-section { display: grid; grid-template-columns: .8fr 1.4fr; gap: 70px; }
.faq-list { border-top: 1px solid var(--line); }
.faq-list details { border-bottom: 1px solid var(--line); }
.faq-list summary { display: flex; align-items: center; justify-content: space-between; gap: 20px; padding-block: 21px; list-style: none; font-size: 15px; font-weight: 550; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary > span { font-size: 22px; color: var(--purple); font-weight: 400; }
.faq-list details[open] summary > span { transform: rotate(45deg); }
.faq-list details > p { color: var(--muted); font-size: 14px; margin: 0 26px 22px 0; }
.faq-list a { text-decoration: underline; color: var(--purple); }
.closing-section { border-top: 1px solid var(--line); text-align: center; padding-block: 55px 75px; }
.closing-section > p { color: var(--muted); font-size: 14px; }
.closing-section h2 { font-size: clamp(27px, 3.2vw, 41px); letter-spacing: -1.1px; font-weight: 680; line-height: 1.2; margin: 12px 0 25px; }
.closing-login { display: block; color: var(--muted); font-size: 12px; width: fit-content; margin: 18px auto 0; }
.closing-login:hover { color: var(--purple); }
.site-footer { border-top: 1px solid var(--line); background: white; }
.footer-inner { display: flex; align-items: center; gap: 40px; padding-block: 29px; }
.site-footer .brand { font-size: 14px; }
.site-footer .brand-mark { width: 28px; height: 30px; border-radius: 9px 9px 9px 2px; font-size: 18px; }
.footer-inner > p { color: var(--muted); font-size: 11px; }
.footer-links { display: flex; gap: 22px; margin-left: auto; color: var(--muted); font-size: 12px; }
.copyright { font-size: 11px; color: var(--muted); }
/* Authentication shares the public identity and keeps native password-manager fields. */
.auth-layout { width: min(940px, calc(100% - 80px)); min-height: calc(100dvh - 200px); margin: 0 auto; display: grid; grid-template-columns: 1fr 1fr; gap: 90px; align-items: center; padding-block: 60px; }
.auth-intro h1 { font-size: 43px; line-height: 1.14; letter-spacing: -1.6px; margin: 18px 0; }
.auth-intro h1 span { color: var(--purple); }
.auth-intro > p:not(.eyebrow) { color: var(--muted); font-size: 16px; line-height: 1.8; }
.auth-intro .inline-action { margin-top: 25px; }
.auth-card { background: white; border: 1px solid var(--line); border-radius: 18px; padding: 32px; box-shadow: 0 14px 40px #25205e07; }
.auth-card h2 { font-size: 25px; letter-spacing: -.5px; line-height: 1.2; }
.auth-caption { color: var(--muted); font-size: 13px; margin: 9px 0 23px; }
.auth-field { margin-top: 18px; }
.auth-field label { display: block; font-size: 13px; font-weight: 500; margin-bottom: 7px; }
.auth-field input { width: 100%; min-width: 0; min-height: 48px; border: 1px solid #daddE8; border-radius: 8px; padding: 11px 13px; background: #fcfcfe; color: var(--ink); font-size: 16px; }
.auth-field input:focus { border-color: var(--purple); }
.password-wrap { position: relative; }
.password-wrap input { padding-right: 53px; }
.password-toggle { position: absolute; inset: 1px 1px 1px auto; width: 45px; border: 0; border-radius: 0 7px 7px 0; background: transparent; display: grid; place-items: center; color: var(--muted); }
.password-toggle svg { width: 20px; height: 20px; }
.remember-row { display: flex; gap: 8px; align-items: flex-start; margin: 19px 0; color: var(--muted); font-size: 11px; }
.remember-row input { margin-top: 3px; accent-color: var(--purple); }
.auth-submit { width: 100%; }
.auth-register { border-top: 1px solid var(--line); margin-top: 24px; padding-top: 20px; font-size: 12px; text-align: center; color: var(--muted); }
.auth-register a { color: var(--purple); font-weight: 600; display: inline-block; padding: 5px 0; }
.auth-error { margin: 0 0 17px; border-radius: 8px; background: #fff0ef; color: #a5362c; padding: 12px; font-size: 13px; }
@media (min-width: 1450px) { .hero { padding-block: 95px 70px; } }
@media (max-width: 1080px) {
  .container { width: calc(100% - 56px); }
  .header-inner { gap: 24px; }
  .header-nav { gap: 20px; }
  .hero { gap: 32px; padding-block: 60px 44px; }
  .hero h1 { font-size: 44px; letter-spacing: -2px; }
  .hero-lead { font-size: 16px; }
  .hero-actions { gap: 7px; }
  .hero-actions .button { padding-inline: 15px; font-size: 13px; }
  .demo-panel { padding-inline: 14px; }
  .demo-status { flex-wrap: wrap; }
  .section-intro { gap: 28px; }
  .feature-card { padding: 23px; }
  .feature-board, .feature-bank { padding-bottom: 0; }
  .annotation { font-size: 11px; right: 14px; }
  .method-grid { gap: 60px; }
  .start-section { padding: 43px; gap: 43px; }
  .footer-inner { flex-wrap: wrap; gap: 20px 30px; }
  .auth-layout { gap: 55px; }
}
@media (max-width: 800px) {
  .header-inner { min-height: 78px; gap: 18px; }
  .header-nav { gap: 16px; font-size: 12px; }
  .brand { font-size: 15px; }
  .hero { grid-template-columns: 1fr; gap: 40px; padding-top: 50px; }
  .hero-copy { max-width: 610px; }
  .hero h1 { font-size: 54px; }
  .hero-lead { max-width: 540px; font-size: 17px; }
  .hero-actions .button { font-size: 15px; padding-inline: 22px; }
  .demo-wrap { width: min(100%, 560px); margin: 0 auto; }
  .section { padding-block: 70px; }
  .section-intro { flex-direction: column; align-items: flex-start; gap: 18px; }
  .section-intro > p { max-width: 500px; }
  .session-banner > img { height: 300px; }
  .session-banner-copy { padding-inline: 26px; }
  .features-section { padding-top: 62px; }
  .feature-repeat, .feature-ai { display: grid; grid-template-columns: 40px 1fr; column-gap: 20px; }
  .feature-icon { grid-row: span 4; }
  .feature-bank h3, .feature-repeat h3, .feature-ai h3 { margin-top: 4px; }
  .feature-bank p, .feature-repeat p, .feature-ai p { margin-top: 8px; }
  .topic-tags { grid-column: 2; margin-top: 15px; }
  .board-illustration { padding-inline: 14px; }
  .illustration-equation { font-size: 20px; }
  .annotation { position: static; max-width: none; margin-top: 12px; transform: none; }
  .exam-illustration { padding-inline: 14px; }
  .method-grid { gap: 35px; }
  .method-section { padding-block: 55px; }
  .method-section h2 { font-size: 34px; }
  .people-grid { gap: 25px; }
  .people-grid h3 { font-size: 18px; }
  .people-grid p { font-size: 13px; }
  .start-section { padding: 35px; gap: 30px; }
  .start-section h2 { font-size: 31px; }
  .faq-section { grid-template-columns: 1fr; gap: 30px; }
  .auth-layout { width: min(470px, calc(100% - 40px)); grid-template-columns: 1fr; gap: 28px; padding-block: 35px 50px; }
  .auth-intro h1 { font-size: 33px; }
  .auth-intro > p:not(.eyebrow), .auth-intro .inline-action { display: none; }
}
@media (max-width: 620px) {
  :root { scroll-padding-top: 130px; }
  .container { width: calc(100% - 36px); }
  .header-inner { flex-wrap: wrap; gap: 10px; padding-block: 13px 10px; min-height: 0; }
  .brand { font-size: 14px; gap: 8px; }
  .brand-mark { width: 29px; height: 32px; font-size: 19px; border-radius: 10px 10px 10px 2px; }
  .header-inner > .button { margin-left: auto; min-height: 38px; padding: 8px 12px; gap: 10px; font-size: 12px; }
  .header-nav { order: 3; width: 100%; margin-left: 0; justify-content: space-between; gap: 8px; }
  .header-nav a { padding: 5px 3px; }
  .hero { padding-block: 38px 32px; gap: 31px; }
  .eyebrow { font-size: 10px; letter-spacing: 1.3px; }
  .eyebrow-line { width: 13px; margin-right: 4px; }
  .hero h1 { font-size: clamp(35px, 8.9vw, 47px); letter-spacing: -1.55px; line-height: 1.13; margin-top: 18px; }
  .desktop-break { display: none; }
  .hero-lead { margin-top: 19px; font-size: 16px; }
  .hero-actions { margin-top: 23px; gap: 9px; }
  .hero-actions .button { font-size: 13px; padding-inline: 15px; gap: 12px; min-height: 48px; }
  .hero-actions .button-text { padding-left: 2px; }
  .hero-note { margin-top: 16px; font-size: 11px; }
  .demo-wrap { scroll-margin-top: 125px; }
  .demo-caption { font-size: 10px; }
  .demo-titlebar { padding: 15px; }
  .demo-tabs { padding-inline: 9px; }
  .demo-tab { font-size: 11px; min-height: 42px; }
  .demo-tab span { font-size: 9px; }
  .demo-panel { padding: 18px 12px 0; }
  .panel-heading { gap: 8px; }
  .panel-heading h2 { font-size: 13px; }
  .small-badge { font-size: 9px; }
  .equation { font-size: 25px; }
  .example-board { padding-left: 34px; min-height: 216px; }
  .board-solution { font-size: 21px; }
  .board-prompt { font-size: 11px; }
  .practice-example, .result-example { min-height: 216px; }
  .practice-example { padding: 22px 12px 12px; }
  .demo-panel-footer { min-height: 60px; gap: 6px; }
  .demo-panel-footer > span { max-width: 44%; }
  .demo-panel-footer .inline-action { font-size: 10px; min-height: 44px; }
  .demo-status { font-size: 9px; padding: 10px 12px; gap: 4px 10px; }
  .demo-under-caption { font-size: 10px; margin-top: 11px; }
  .benefit-strip { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px 14px; padding-block: 17px; }
  .benefit-strip p { justify-content: flex-start; gap: 8px; font-size: 11px; }
  .benefit-strip p:last-child { grid-column: 1 / -1; }
  .benefit-strip .icon { width: 18px; height: 18px; }
  .section { padding-block: 58px; }
  .section h2, .start-section h2 { font-size: 29px; letter-spacing: -.9px; }
  .section-intro { margin-bottom: 27px; gap: 15px; }
  .section-intro > p { font-size: 13px; }
  .session-banner { grid-template-columns: 1fr; border-radius: 13px; margin-top: 18px; }
  .session-banner > img { height: auto; width: 100%; aspect-ratio: 16 / 9; object-position: center 49%; }
  .session-banner-copy { padding: 20px 22px 23px; }
  .session-banner-copy h2 { font-size: 23px; margin-top: 9px; }
  .session-banner-copy > p:last-child { font-size: 13px; margin-top: 8px; }
  .features-section { padding-top: 48px; }
  .feature-grid { grid-template-columns: 1fr; gap: 15px; }
  .feature-card { grid-column: auto; padding: 23px; }
  .feature-board, .feature-bank { padding-bottom: 0; }
  .feature-card p { font-size: 13px; }
  .feature-repeat, .feature-ai { display: block; }
  .feature-bank h3, .feature-repeat h3, .feature-ai h3 { margin-top: 12px; }
  .feature-card h3 { font-size: 20px; }
  .feature-board h3, .feature-bank h3 { font-size: 25px; }
  .exam-illustration { min-height: 225px; margin-top: 25px; padding-inline: 13px; }
  .board-illustration { min-height: 253px; padding: 19px; }
  .annotation { position: absolute; font-size: 10px; bottom: 37px; right: 10px; max-width: 48%; }
  .illustration-equation { font-size: 21px; }
  .method-section { padding-block: 49px; }
  .method-grid { grid-template-columns: 1fr; gap: 35px; }
  .method-section h2 { font-size: 35px; }
  .section-text { font-size: 14px; }
  .learning-route li { padding-bottom: 27px; }
  .learning-route h3 { font-size: 15px; }
  .learning-route p { font-size: 12px; }
  .people-grid { grid-template-columns: 1fr; gap: 25px; }
  .people-grid article { padding-top: 20px; }
  .people-grid h3 { margin-top: 9px; }
  .start-section { grid-template-columns: 1fr; padding: 29px 24px; gap: 35px; border-radius: 16px; }
  .start-heading > p:not(.eyebrow) { font-size: 13px; }
  .start-steps li { gap: 15px; margin-top: 24px; }
  .start-steps h3 { font-size: 15px; }
  .start-steps p { font-size: 12px; }
  .faq-section { gap: 27px; }
  .faq-list summary { font-size: 14px; padding-block: 19px; gap: 17px; }
  .faq-list details > p { font-size: 13px; margin-right: 9px; }
  .closing-section { padding-block: 39px 45px; }
  .closing-section > p { font-size: 12px; }
  .closing-section h2 { font-size: 28px; letter-spacing: -.9px; }
  .footer-inner { gap: 20px; padding-block: 25px; justify-content: space-between; }
  .footer-inner > p { width: 100%; order: 2; }
  .footer-links { margin-left: 0; width: 100%; order: 3; }
  .copyright { margin-left: auto; }
  .auth-layout { width: calc(100% - 36px); gap: 23px; }
  .auth-intro h1 { font-size: 31px; margin-bottom: 0; }
  .auth-card { padding: 25px 22px; border-radius: 14px; }
  .auth-card h2 { font-size: 23px; }
}
@media (max-width: 360px) {
  .hero h1 { font-size: 33px; }
  .hero-actions { align-items: stretch; flex-direction: column; }
  .hero-actions .button-text { justify-content: flex-start; }
  .demo-panel { padding-inline: 9px; }
  .small-badge { padding-inline: 4px; font-size: 8px; }
  .equation { font-size: 23px; }
  .board-solution { font-size: 18px; }
  .board-prompt { font-size: 10px; }
  .annotation { position: static; max-width: none; }
  .illustration-equation { font-size: 18px; }
  .demo-under-caption { font-size: 9px; }
}
@media (prefers-reduced-motion: reduce) {
  :root { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}