@charset "UTF-8";
:root {
    color-scheme: light;
    --paper: #f7f8fa;
    --surface: #ffffff;
    --ink: #202b3b;
    --muted: #647080;
    --line: #dfe4eb;
    --brand: #3c62ca;
    --brand-deep: #3154b2;
    --brand-content: #ffffff;
    --soft: #edf0f5;
    --radius: 10px;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    font-synthesis: none;
    background: var(--paper);
    color: var(--ink);
}
:root[data-theme="flashcard-dark"] {
    color-scheme: dark;
    --paper: #25282d;
    --surface: #2e3239;
    --ink: #eef1f7;
    --muted: #b0b9c8;
    --line: #434b58;
    --brand: #a7bbff;
    --brand-deep: #b9c9ff;
    --brand-content: #1c2c50;
    --soft: #373e48;
}
@media (prefers-color-scheme: dark) {
    :root:not([data-theme]) {
        color-scheme: dark;
        --paper: #25282d;
        --surface: #2e3239;
        --ink: #eef1f7;
        --muted: #b0b9c8;
        --line: #434b58;
        --brand: #a7bbff;
        --brand-deep: #b9c9ff;
        --brand-content: #1c2c50;
        --soft: #373e48;
    }
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-height: 100dvh; display: flex; flex-direction: column; }
body > main { flex: 1; }
button, input, select { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
a { color: inherit; text-decoration: none; }
button { cursor: pointer; }
a:focus-visible, button:focus-visible, summary:focus-visible { outline: 2px solid var(--brand); outline-offset: 5px; }
.wrap { width: min(1040px, calc(100% - 96px)); margin-inline: auto; }
.site-header { min-height: 90px; display: flex; align-items: center; justify-content: space-between; gap: 24px; border-bottom: 1px solid var(--line); }
.brand { display: inline-flex; align-items: center; gap: 10px; font-size: 18px; font-weight: 650; letter-spacing: -.65px; white-space: nowrap; }
.brand-light { font-weight: 400; }
.brand-mark { display: block; width: 36px; height: 36px; border-radius: 9px; flex-shrink: 0; }
.site-navigation { display: flex; align-items: center; gap: 28px; font-size: 13px; color: var(--muted); }
.site-navigation a { padding-block: 12px; }
.site-navigation a:hover, .quiet-link:hover { color: var(--ink); }
.quiet-link { font-size: 13px; color: var(--muted); }
.eyebrow { font-size: 11px; letter-spacing: 1.7px; font-weight: 600; color: var(--muted); }
.little-dot { display: inline-block; width: 5px; height: 5px; border-radius: 50%; background: var(--brand); margin-right: 7px; vertical-align: middle; }
.home-page { position: relative; isolation: isolate; overflow-x: clip; }
.home-page > header, .home-page > main, .home-page > footer { position: relative; z-index: 1; }
.hero { display: grid; gap: 38px; text-align: center; padding-block: 46px 40px; }
.hero h1 { font-size: clamp(42px, 5.2vw, 58px); line-height: 1.06; letter-spacing: -2.5px; font-weight: 650; margin: 20px 0; }
.hero h1 span { color: var(--brand); }
.hero-description { max-width: 510px; margin: auto; font-size: 15px; line-height: 1.85; color: var(--muted); }
.hero-actions { display: flex; justify-content: center; align-items: center; flex-wrap: wrap; gap: 20px; margin-top: 25px; }
.button { display: inline-flex; align-items: center; justify-content: center; gap: 16px; min-height: 44px; border-radius: 8px; padding: 12px 18px; font-size: 13px; font-weight: 550; border: 1px solid transparent; }
.button-dark { background: var(--brand); color: var(--brand-content); }
.button-dark:hover { background: var(--brand-deep); }
.button-light { border-color: var(--line); background: var(--surface); color: var(--ink); }
.button-light:hover { background: var(--soft); }
.platform-note { font-size: 11px; color: var(--muted); margin-top: 18px; }
.practice-preview { width: min(100%, 570px); margin: auto; padding: 24px 28px; display: grid; grid-template-columns: 1fr 1fr; column-gap: 32px; align-items: center; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); text-align: left; box-shadow: 0 20px 45px -35px color-mix(in srgb, var(--ink) 30%, transparent); scroll-margin-top: 24px; }
.practice-preview-header, .practice-preview-footer { display: flex; justify-content: space-between; gap: 12px; font-size: 12px; color: var(--muted); grid-column: 1/-1; }
.practice-preview-progress { grid-column: 1/-1; display: flex; gap: 5px; margin-block: 20px 24px; }
.practice-preview-progress span { height: 3px; flex: 1; background: var(--soft); border-radius: 3px; }
.practice-preview-progress span:nth-child(-n+2) { background: var(--brand); }
.practice-preview-word h2 { font-size: 40px; font-weight: 550; letter-spacing: -1.8px; line-height: 1.2; margin: 13px 0 10px; }
.practice-preview-word .eyebrow { font-size: 10px; }
.practice-preview-word .muted { font-size: 13px; }
.practice-preview-answer { display: flex; flex-direction: column; font-size: 14px; line-height: 1.7; }
.practice-preview-answer summary { display: block; cursor: pointer; background: var(--soft); padding: 12px; border-radius: 7px; text-align: center; font-size: 13px; font-weight: 550; list-style: none; }
.practice-preview-answer summary::-webkit-details-marker { display: none; }
.practice-preview-answer p { margin-bottom: 0; color: var(--muted); }
.practice-preview-answer .hide-label { display: none; }
.practice-preview-answer[open] .hide-label { display: inline; }
.practice-preview-answer[open] .reveal-label { display: none; }
.practice-preview-footer { font-size: 11px; margin-top: 25px; }
.header-atmosphere { position: absolute; inset: 0 0 auto; height: 660px; pointer-events: none; z-index: 0; overflow: clip; }
.floating-tile { position: absolute; display: block; width: var(--width); height: var(--height); left: var(--left, auto); right: var(--right, auto); top: var(--top); opacity: var(--opacity, .7); background: color-mix(in srgb, var(--brand) 5%, transparent); border: 1px solid color-mix(in srgb, var(--brand) 12%, transparent); border-radius: 16px; filter: blur(var(--blur)); transform: perspective(700px) rotateX(var(--tilt-x)) rotateY(var(--tilt-y)) rotate(var(--angle)) skewX(var(--skew)); animation: tile-drift var(--duration) ease-in-out infinite; animation-delay: var(--delay); }
.floating-tile::after { content: ""; position: absolute; left: 20%; right: 20%; top: 34%; height: 2px; border-radius: 2px; background: color-mix(in srgb, var(--brand) 10%, transparent); box-shadow: 0 9px 0 color-mix(in srgb, var(--brand) 7%, transparent); }
.floating-tile:nth-child(1) { --width:150px; --height:105px; --left:2%; --top:140px; --angle:-13deg; --duration:26s; --delay:-7s; --blur:.3px; --tilt-x:8deg; --tilt-y:-15deg; --skew:-4.5deg; }
.floating-tile:nth-child(2) { --width:112px; --height:150px; --right:6%; --top:112px; --angle:11deg; --duration:29s; --delay:-15s; --blur:1.6px; --tilt-x:-9deg; --tilt-y:18deg; --skew:4.5deg; --opacity:.57; }
.floating-tile:nth-child(3) { --width:132px; --height:88px; --left:-36px; --top:400px; --angle:8deg; --duration:23s; --delay:-3s; --blur:3.2px; --tilt-x:12deg; --tilt-y:-10deg; --skew:4.5deg; --opacity:.45; }
.floating-tile:nth-child(4) { --width:150px; --height:103px; --right:-40px; --top:375px; --angle:-8deg; --duration:31s; --delay:-20s; --blur:.8px; --tilt-x:-6deg; --tilt-y:14deg; --skew:-4.5deg; --opacity:.63; }
.floating-tile:nth-child(5) { --width:54px; --height:39px; --left:24%; --top:490px; --angle:-18deg; --duration:22s; --delay:-11s; --blur:2.1px; --tilt-x:9deg; --tilt-y:-12deg; --skew:4.5deg; --opacity:.52; }
@keyframes tile-drift {
    0%,100% { transform: perspective(700px) translate3d(0,0,0) rotateX(var(--tilt-x)) rotateY(var(--tilt-y)) rotate(var(--angle)) skewX(var(--skew)); }
    50% { transform: perspective(700px) translate3d(9px,-17px,0) rotateX(var(--tilt-x)) rotateY(var(--tilt-y)) rotate(calc(var(--angle) + 4deg)) skewX(var(--skew)); }
}
.how { display: grid; grid-template-columns: repeat(3, 1fr); gap: 42px; padding-block: 32px; border-block: 1px solid var(--line); scroll-margin-top: 24px; }
.feature-number { color: var(--muted); font: 11px ui-monospace, monospace; }
.how h2 { font-size: 14px; font-weight: 600; margin: 12px 0 8px; }
.how p { font-size: 12px; line-height: 1.85; color: var(--muted); margin: 0; }
.ai-feature { display: grid; grid-template-columns: 1fr 1fr; gap: 65px; padding-block: 56px; border-bottom: 1px solid var(--line); scroll-margin-top: 24px; }
.ai-feature h2 { font-size: clamp(28px, 3vw, 36px); line-height: 1.2; letter-spacing: -1px; font-weight: 550; margin: 20px 0; }
.ai-feature p:not(.eyebrow) { font-size: 14px; line-height: 1.85; color: var(--muted); }
.ai-feature-details article + article { border-top: 1px solid var(--line); padding-top: 18px; margin-top: 18px; }
.ai-feature h3 { font-size: 14px; font-weight: 600; margin-bottom: 8px; }
.site-footer { display: flex; align-items: center; flex-wrap: wrap; gap: 24px; padding-block: 25px; font-size: 11px; color: var(--muted); }
.site-footer-legal { display: flex; align-items: center; gap: 16px; margin-left: auto; white-space: nowrap; }
.site-footer a:hover { color: var(--ink); }
.muted { color: var(--muted); }
.privacy-page { max-width: 780px; padding-block: 44px 72px; }
.privacy-page h1 { font-size: clamp(44px, 7vw, 64px); font-weight: 550; letter-spacing: -2px; margin: 22px 0; }
.privacy-intro { font-size: 19px; line-height: 1.7; color: var(--muted); }
.privacy-date { font-size: 12px; color: var(--muted); margin-bottom: 38px; }
.privacy-page section { padding-block: 22px; border-top: 1px solid var(--line); }
.privacy-page h2 { font-size: 20px; font-weight: 550; letter-spacing: -.3px; margin: 0 0 15px; }
.privacy-page section p, .privacy-page li { font-size: 15px; line-height: 1.85; color: var(--muted); }
.privacy-page a { color: var(--brand-deep); text-decoration: underline; text-underline-offset: 3px; overflow-wrap: anywhere; }
.privacy-page li+li { margin-top: 8px; }
.announcement-bar { position: relative; z-index: 2; background: var(--soft); border-bottom: 1px solid var(--line); color: var(--ink); }
.announcement-content { display: flex; align-items: flex-start; justify-content: space-between; gap: 1rem; padding-block: .85rem; }
.announcement-content>div { min-width: 0; }
.announcement-content strong { display: block; font-size: .9rem; font-weight: 600; }
.announcement-content span { display: block; white-space: pre-wrap; overflow-wrap: anywhere; font-size: .85rem; margin-top: .2rem; }
.announcement-content form { flex-shrink: 0; }
.announcement-content button { border: 0; background: transparent; color: inherit; font-size: 1.5rem; min-width: 44px; min-height: 44px; border-radius: 8px; }
.announcement-content button:hover { background: var(--surface); }
.announcement-link { display: block; flex: 1; min-width: 0; color: inherit; }
.announcement-link:hover strong { text-decoration: underline; }
@media(max-width: 740px) {
    .wrap { width: calc(100% - 48px); }
    .ai-feature { gap: 32px; }
    .how { gap: 24px; }
}
@media(max-width: 520px) {
    .wrap { width: calc(100% - 40px); }
    .site-header { min-height: 80px; gap: 12px; flex-wrap: wrap; padding-block: 18px; }
    .brand { font-size: 16px; gap: 8px; }
    .site-navigation { gap: 16px; font-size: 12px; }
    .hero { text-align: left; padding-block: 35px; gap: 30px; }
    .hero h1 { font-size: 43px; letter-spacing: -2px; }
    .hero-description { font-size: 14px; }
    .hero-actions { justify-content: flex-start; gap: 13px; }
    .practice-preview { display: block; padding: 23px; }
    .practice-preview-word { margin-block: 24px; }
    .practice-preview-word h2 { font-size: 38px; }
    .practice-preview-answer p { min-height: 48px; }
    .how, .ai-feature { grid-template-columns: 1fr; gap: 25px; padding-block: 30px; }
    .how article { display: grid; grid-template-columns: 24px 1fr; gap: 0 12px; }
    .feature-number { grid-row: 1/3; padding-top: 3px; }
    .how h2 { margin: 0 0 6px; }
    .how p { grid-column: 2; }
    .site-footer { gap: 15px; }
    .floating-tile:nth-child(n+3) { display: none; }
    .floating-tile:first-child { left: -70px; top: 145px; }
    .floating-tile:nth-child(2) { right: -60px; top: 360px; }
}
@media(prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    .floating-tile { animation: none; }
}
@media(pointer: coarse) {
    .site-navigation a, .quiet-link { display: inline-flex; align-items: center; min-height: 44px; }
}

/* Quiet-stack emblem: the same paper layers used by the native splash screen. */
.quiet-stack {
    position: relative;
    isolation: isolate;
    width: min(280px, 100%);
    height: 260px;
    margin: auto;
    pointer-events: none;
}
.quiet-stack::before {
    content: "";
    position: absolute;
    inset: -20px;
    z-index: -1;
    background: radial-gradient(ellipse, rgb(17 129 107 / 14%), transparent 70%);
    filter: blur(20px);
}
.quiet-stack-card {
    position: absolute;
    left: calc(50% - 80px);
    top: 30px;
    width: 160px;
    height: 200px;
    border: 1px solid var(--line);
    border-radius: 24px;
    background: var(--surface);
    box-shadow: 0 14px 30px -12px color-mix(in srgb, var(--ink) 18%, transparent);
}
.quiet-stack-card-back { transform: translate(-14px, -4px) rotate(-14deg); }
.quiet-stack-card-front { transform: translate(14px, 4px) rotate(10deg); }
.quiet-stack-logo {
    position: absolute;
    left: calc(50% - 70px);
    top: 56px;
    width: 140px;
    height: 140px;
    border-radius: 32px;
    transform: rotate(-3deg);
    box-shadow: 0 16px 28px -10px color-mix(in srgb, var(--ink) 20%, transparent);
}
@media (min-width: 800px) {
    .hero--quiet-stack { grid-template-columns: minmax(0, 1fr) minmax(260px, .75fr); }
    .hero--quiet-stack > .quiet-stack { grid-column: 2; grid-row: 1; }
    .hero--quiet-stack > .hero-copy { grid-column: 1; grid-row: 1; text-align: left; }
    .hero--quiet-stack .hero-description { margin-inline: 0; }
    .hero--quiet-stack .hero-actions { justify-content: flex-start; }
    .hero--quiet-stack > .practice-preview { grid-column: 1 / -1; }
}