:root {
  color-scheme: dark;
  --bg: #07100d;
  --surface: #0d1714;
  --surface-2: #111f1b;
  --surface-3: #162823;
  --text: #f1f7f4;
  --muted: #9fb1a9;
  --green: #37e88b;
  --green-2: #15bd69;
  --cyan: #48d5d0;
  --line: rgba(202, 240, 220, .13);
  --line-strong: rgba(55, 232, 139, .35);
  --danger: #ffca78;
  --shadow: 0 24px 70px rgba(0, 0, 0, .38);
  --radius: 18px;
  --container: 1240px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 96px; }
body {
  margin: 0;
  background:
    radial-gradient(circle at 12% 8%, rgba(27, 145, 90, .13), transparent 29rem),
    radial-gradient(circle at 88% 25%, rgba(24, 127, 126, .1), transparent 32rem),
    var(--bg);
  color: var(--text);
  font-family: Inter, "Noto Sans SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image: linear-gradient(rgba(255,255,255,.018) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,.018) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: linear-gradient(to bottom, black, transparent 72%);
}
a { color: inherit; }
button, input { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
img { max-width: 100%; display: block; }
:focus-visible { outline: 3px solid rgba(72, 213, 208, .9); outline-offset: 3px; }
.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; }
.skip-link { position: fixed; z-index: 999; left: 16px; top: 12px; padding: 10px 14px; border-radius: 10px; background: var(--green); color: #03110a; font-weight: 800; transform: translateY(-150%); transition: transform .2s; }
.skip-link:focus { transform: none; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  border-bottom: 1px solid transparent;
  background: rgba(7, 16, 13, .76);
  backdrop-filter: blur(18px) saturate(130%);
  transition: border-color .2s, box-shadow .2s;
}
.site-header.is-scrolled { border-color: var(--line); box-shadow: 0 12px 32px rgba(0,0,0,.22); }
.nav-shell { max-width: var(--container); min-height: 74px; margin: 0 auto; padding: 0 24px; display: flex; align-items: center; gap: 28px; }
.brand { display: inline-flex; align-items: center; gap: 11px; text-decoration: none; flex: 0 0 auto; }
.brand img { width: 42px; height: 42px; object-fit: contain; border-radius: 11px; }
.brand span { display: grid; line-height: 1.2; }
.brand b { font-size: 15px; letter-spacing: .03em; }
.brand small { color: var(--muted); font-size: 10px; margin-top: 4px; }
.site-nav { display: flex; align-items: center; gap: 4px; margin-left: auto; }
.site-nav a { position: relative; padding: 10px 12px; color: #b9c8c1; text-decoration: none; font-size: 13px; border-radius: 9px; transition: color .2s, background .2s; }
.site-nav a:hover { color: var(--text); background: rgba(255,255,255,.04); }
.site-nav a[aria-current="page"] { color: var(--green); background: rgba(55,232,139,.08); }
.nav-cta { padding: 10px 14px; color: #05120b; background: var(--green); border-radius: 10px; text-decoration: none; font-size: 13px; font-weight: 800; box-shadow: 0 8px 24px rgba(55,232,139,.16); }
.menu-button { display: none; width: 44px; height: 44px; margin-left: auto; padding: 10px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); color: var(--text); cursor: pointer; }
.menu-button i { display: block; height: 2px; margin: 4px 0; background: currentColor; border-radius: 3px; }

main { overflow: hidden; }
.hero { position: relative; max-width: var(--container); min-height: 650px; margin: 0 auto; padding: 92px 24px 72px; display: grid; grid-template-columns: 1.05fr .85fr; gap: clamp(36px, 7vw, 90px); align-items: center; }
.hero-glow { position: absolute; width: 380px; height: 380px; left: -160px; top: 40px; border-radius: 50%; background: rgba(55,232,139,.09); filter: blur(90px); pointer-events: none; }
.hero-copy { position: relative; z-index: 1; }
.eyebrow { margin: 0 0 18px; color: #87a59a; font-size: 11px; font-weight: 800; letter-spacing: .17em; }
.eyebrow span { display: inline-block; width: 25px; height: 1px; margin: 0 10px 3px 0; background: var(--green); box-shadow: 0 0 12px var(--green); }
h1, h2, h3, p { text-wrap: pretty; }
h1 { margin: 0; font-size: clamp(43px, 5.8vw, 78px); line-height: 1.08; letter-spacing: -.055em; }
h1 em { color: var(--green); font-style: normal; text-shadow: 0 0 35px rgba(55,232,139,.15); }
.hero-lead { max-width: 640px; margin: 26px 0 0; color: #b1c2ba; font-size: clamp(15px, 1.5vw, 18px); line-height: 1.85; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 32px; }
.button { min-height: 46px; padding: 11px 18px; display: inline-flex; align-items: center; justify-content: center; gap: 10px; border: 1px solid transparent; border-radius: 11px; text-decoration: none; font-size: 14px; font-weight: 800; cursor: pointer; transition: transform .2s, border-color .2s, background .2s; }
.button:hover { transform: translateY(-2px); }
.button-primary { color: #04120b; background: linear-gradient(135deg, #55f19d, #26cd77); box-shadow: 0 14px 32px rgba(27, 196, 110, .17); }
.button-secondary { color: var(--text); background: rgba(255,255,255,.035); border-color: var(--line); }
.button-secondary:hover { border-color: var(--line-strong); background: rgba(55,232,139,.06); }
.trust-points { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; max-width: 560px; margin: 42px 0 0; padding: 24px 0 0; border-top: 1px solid var(--line); list-style: none; }
.trust-points li { display: grid; gap: 1px; }
.trust-points b { font-size: 22px; color: var(--text); }
.trust-points span { font-size: 11px; color: var(--muted); }
.hero-visual { position: relative; margin: 0; padding: 13px; border: 1px solid var(--line); border-radius: 26px; background: linear-gradient(145deg, rgba(255,255,255,.045), rgba(255,255,255,.01)); box-shadow: var(--shadow); transform: rotate(1deg); }
.hero-visual::before { content: ""; position: absolute; inset: 11%; z-index: -1; background: rgba(35, 225, 133, .23); filter: blur(70px); }
.hero-visual img { width: 100%; aspect-ratio: 1; border-radius: 17px; object-fit: cover; }
.hero-visual figcaption { position: absolute; left: 30px; bottom: 28px; display: inline-flex; align-items: center; gap: 8px; padding: 8px 11px; border: 1px solid rgba(255,255,255,.14); border-radius: 999px; background: rgba(5,12,10,.84); color: #b7c8c0; font-size: 10px; backdrop-filter: blur(10px); }
.live-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--green); box-shadow: 0 0 0 4px rgba(55,232,139,.12); }

.safety-strip { max-width: var(--container); margin: 0 auto 34px; padding: 18px 24px; display: grid; grid-template-columns: auto 1fr auto; gap: 14px; align-items: center; border: 1px solid rgba(255,202,120,.22); border-radius: 14px; background: rgba(255,183,77,.045); }
.safety-strip p { margin: 0; color: #cbbda6; font-size: 13px; }
.safety-strip b { color: #ffe0a6; }
.safety-strip a { color: #ffe0a6; font-size: 12px; white-space: nowrap; text-underline-offset: 4px; }
.safety-icon { width: 25px; height: 25px; display: grid; place-items: center; border-radius: 50%; color: #1c1404; background: var(--danger); font-weight: 900; }

.library { max-width: var(--container); margin: 0 auto; padding: 96px 24px 80px; }
.section-heading { display: flex; justify-content: space-between; gap: 30px; align-items: end; }
.section-heading h2, .learning-path h2, .source-note h2 { margin: 0; font-size: clamp(32px, 4.3vw, 52px); line-height: 1.1; letter-spacing: -.045em; }
.section-heading > div > p:last-child { max-width: 670px; margin: 16px 0 0; color: var(--muted); font-size: 14px; }
.result-count { display: grid; text-align: right; line-height: 1; }
.result-count strong { color: var(--green); font-size: 38px; }
.result-count span { margin-top: 7px; color: var(--muted); font-size: 11px; }
.library-tools { display: grid; grid-template-columns: 1fr auto; gap: 12px; margin-top: 38px; }
.search-box { min-height: 52px; display: flex; align-items: center; gap: 12px; padding: 0 15px; border: 1px solid var(--line); border-radius: 13px; background: rgba(12,23,19,.8); transition: border-color .2s, box-shadow .2s; }
.search-box:focus-within { border-color: var(--line-strong); box-shadow: 0 0 0 4px rgba(55,232,139,.06); }
.search-box svg, .bookmark-filter svg { width: 20px; fill: none; stroke: currentColor; stroke-width: 1.8; }
.search-box svg { color: #6e887d; }
.search-box input { width: 100%; border: 0; outline: 0; background: transparent; color: var(--text); font-size: 14px; }
.search-box input::placeholder { color: #6f847b; }
kbd { padding: 4px 7px; border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 6px; color: #789086; background: rgba(0,0,0,.23); font-size: 10px; white-space: nowrap; }
.bookmark-filter { min-height: 52px; padding: 0 16px; display: inline-flex; align-items: center; gap: 9px; border: 1px solid var(--line); border-radius: 13px; color: #c2d0ca; background: rgba(12,23,19,.8); cursor: pointer; }
.bookmark-filter span { min-width: 22px; padding: 2px 6px; border-radius: 99px; color: var(--green); background: rgba(55,232,139,.1); font-size: 11px; }
.bookmark-filter[aria-pressed="true"] { color: var(--green); border-color: var(--line-strong); background: rgba(55,232,139,.07); }
.bookmark-filter[aria-pressed="true"] svg { fill: currentColor; }
.filter-row { display: flex; flex-wrap: wrap; gap: 8px; margin: 16px 0 30px; }
.filter-chip { min-height: 38px; padding: 8px 12px; border: 1px solid var(--line); border-radius: 999px; color: #9eb0a8; background: rgba(255,255,255,.018); cursor: pointer; font-size: 12px; transition: .2s; }
.filter-chip span { margin-left: 5px; opacity: .65; }
.filter-chip:hover { color: var(--text); border-color: rgba(255,255,255,.22); }
.filter-chip.is-active { color: #05120b; border-color: var(--green); background: var(--green); font-weight: 800; }

.course-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; }
.course-card { position: relative; min-width: 0; overflow: hidden; border: 1px solid var(--line); border-radius: var(--radius); background: linear-gradient(145deg, rgba(17,31,27,.95), rgba(9,18,15,.95)); box-shadow: 0 10px 32px rgba(0,0,0,.14); transition: transform .25s, border-color .25s, box-shadow .25s; }
.course-card:hover { transform: translateY(-5px); border-color: var(--line-strong); box-shadow: 0 22px 46px rgba(0,0,0,.28); }
.course-open { width: 100%; padding: 0; border: 0; color: inherit; background: transparent; text-align: left; cursor: pointer; }
.course-media { position: relative; aspect-ratio: 16 / 9; overflow: hidden; background: #0a1512; }
.course-media img { width: 100%; height: 100%; object-fit: cover; transition: transform .5s ease; }
.course-card:hover .course-media img { transform: scale(1.035); }
.course-media::after { content: ""; position: absolute; inset: 0; background: linear-gradient(to top, rgba(4,10,8,.62), transparent 58%); }
.play-button { position: absolute; z-index: 2; left: 17px; bottom: 15px; width: 42px; height: 42px; display: grid; place-items: center; border-radius: 50%; color: #04100a; background: var(--green); box-shadow: 0 8px 24px rgba(0,0,0,.3); }
.play-button svg { width: 17px; fill: currentColor; transform: translateX(1px); }
.duration { position: absolute; z-index: 2; right: 13px; bottom: 15px; padding: 5px 8px; border: 1px solid rgba(255,255,255,.12); border-radius: 7px; color: #eef7f2; background: rgba(3,9,7,.76); font-size: 10px; backdrop-filter: blur(8px); }
.course-body { min-height: 185px; padding: 17px 18px 19px; display: flex; flex-direction: column; }
.course-meta { display: flex; justify-content: space-between; gap: 12px; color: var(--green); font-size: 10px; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; }
.course-meta time { color: #6f887d; font-weight: 600; letter-spacing: 0; }
.course-body h3 { margin: 11px 0 0; color: var(--text); font-size: 17px; line-height: 1.45; letter-spacing: -.015em; }
.course-title-en { display: block; margin-top: 3px; color: #769086; font-size: 11px; font-weight: 500; }
.course-body p { margin: 9px 0 0; color: #91a49b; font-size: 12px; line-height: 1.7; }
.bookmark-button { position: absolute; z-index: 3; right: 12px; top: 12px; width: 38px; height: 38px; display: grid; place-items: center; border: 1px solid rgba(255,255,255,.13); border-radius: 10px; color: #d7e4de; background: rgba(5,13,10,.75); backdrop-filter: blur(8px); cursor: pointer; }
.bookmark-button svg { width: 18px; fill: none; stroke: currentColor; stroke-width: 1.8; }
.bookmark-button[aria-pressed="true"] { color: var(--green); border-color: var(--line-strong); }
.bookmark-button[aria-pressed="true"] svg { fill: currentColor; }
.reading-card .course-media { display: grid; place-items: center; background: radial-gradient(circle at 30% 20%, rgba(55,232,139,.12), transparent 56%), #0b1713; }
.reading-symbol { position: relative; z-index: 2; width: 64px; height: 64px; display: grid; place-items: center; border: 1px solid var(--line-strong); border-radius: 18px; color: var(--green); background: rgba(55,232,139,.07); font-size: 26px; font-weight: 800; }
.reading-card .course-body { min-height: 155px; }
.empty-state { padding: 80px 24px; border: 1px dashed var(--line); border-radius: var(--radius); text-align: center; color: var(--muted); }
.empty-state > span { display: block; color: var(--green); font-size: 50px; }
.empty-state h3 { margin: 10px 0 0; color: var(--text); }
.empty-state p { margin: 6px 0 20px; }

.learning-path { max-width: var(--container); margin: 34px auto 0; padding: 70px 24px; display: grid; grid-template-columns: .8fr 1.2fr; gap: clamp(44px, 8vw, 110px); border-top: 1px solid var(--line); }
.path-intro > p:nth-of-type(2) { margin: 18px 0 22px; color: var(--muted); font-size: 14px; line-height: 1.8; }
.path-intro > a { color: var(--green); font-size: 13px; font-weight: 800; text-decoration: none; }
.path-steps { margin: 0; padding: 0; list-style: none; }
.path-steps li { display: grid; grid-template-columns: 54px 1fr; gap: 18px; padding: 22px 0; border-bottom: 1px solid var(--line); }
.path-steps li:first-child { padding-top: 0; }
.path-steps > li > span { color: var(--green); font-family: ui-monospace, SFMono-Regular, Consolas, monospace; font-size: 12px; }
.path-steps b { font-size: 16px; }
.path-steps p { margin: 5px 0 0; color: var(--muted); font-size: 12px; }
.source-note { max-width: var(--container); margin: 0 auto 90px; padding: 46px 24px; display: grid; grid-template-columns: .75fr 1.25fr; gap: clamp(38px, 7vw, 90px); border: 1px solid var(--line); border-radius: 22px; background: linear-gradient(135deg, rgba(55,232,139,.055), rgba(72,213,208,.025)); }
.source-copy p { margin: 0; color: #a9bbb2; font-size: 14px; line-height: 1.9; }
.source-links { display: flex; flex-wrap: wrap; gap: 18px; margin-top: 20px; }
.source-links a { color: var(--green); font-size: 12px; text-underline-offset: 4px; }

.site-footer { border-top: 1px solid var(--line); background: rgba(4,10,8,.45); }
.footer-main { max-width: var(--container); margin: 0 auto; padding: 58px 24px 42px; display: grid; grid-template-columns: 1.6fr repeat(3, .65fr); gap: 55px; }
.footer-brand > p { max-width: 460px; margin: 18px 0 0; color: var(--muted); font-size: 12px; line-height: 1.75; }
.footer-links { display: grid; align-content: start; gap: 10px; }
.footer-links b { margin-bottom: 5px; font-size: 12px; }
.footer-links a { color: var(--muted); text-decoration: none; font-size: 12px; }
.footer-links a:hover { color: var(--green); }
.footer-bottom { max-width: var(--container); margin: 0 auto; padding: 20px 24px 28px; display: flex; justify-content: space-between; gap: 20px; border-top: 1px solid var(--line); color: #6d8279; font-size: 10px; }

.video-dialog { width: min(980px, calc(100vw - 28px)); max-height: calc(100vh - 28px); padding: 0; overflow: auto; border: 1px solid rgba(137,228,183,.23); border-radius: 20px; color: var(--text); background: #0b1512; box-shadow: 0 36px 100px rgba(0,0,0,.72); }
.video-dialog::backdrop { background: rgba(1,6,4,.78); backdrop-filter: blur(8px); }
.dialog-shell { position: relative; }
.dialog-close { position: absolute; z-index: 5; right: 12px; top: 12px; width: 42px; height: 42px; border: 1px solid rgba(255,255,255,.16); border-radius: 50%; color: white; background: rgba(0,0,0,.63); font-size: 24px; line-height: 1; cursor: pointer; }
.player-wrap { position: relative; aspect-ratio: 16 / 9; display: grid; place-items: center; background: #020604; }
.player-wrap video { width: 100%; height: 100%; display: block; background: #000; }
.player-error { position: absolute; inset: 0; padding: 24px; display: grid; place-content: center; justify-items: center; text-align: center; background: #07100d; }
.player-error[hidden] { display: none; }
.player-error span { margin-top: 5px; color: var(--muted); font-size: 12px; }
.player-error a { margin-top: 18px; color: var(--green); font-size: 13px; }
.dialog-content { padding: 24px 28px 28px; }
.dialog-meta { display: flex; gap: 16px; color: var(--green); font-size: 11px; }
.dialog-content h2 { margin: 9px 0 0; font-size: clamp(25px, 4vw, 38px); line-height: 1.2; letter-spacing: -.035em; }
.dialog-content > p { margin: 10px 0 0; color: var(--muted); font-size: 13px; }
.dialog-actions { display: flex; flex-wrap: wrap; gap: 9px; margin-top: 20px; }
.dialog-actions button, .dialog-actions a { min-height: 38px; padding: 8px 12px; border: 1px solid var(--line); border-radius: 9px; color: #c8d6cf; background: rgba(255,255,255,.025); text-decoration: none; font-size: 11px; cursor: pointer; }
.dialog-actions button:hover, .dialog-actions a:hover { color: var(--green); border-color: var(--line-strong); }
.dialog-warning { padding-top: 16px; border-top: 1px solid var(--line); color: #cdbb98 !important; }
.toast { position: fixed; z-index: 100; left: 50%; bottom: 24px; max-width: calc(100vw - 32px); padding: 11px 15px; border: 1px solid var(--line-strong); border-radius: 10px; color: var(--text); background: #10211a; box-shadow: var(--shadow); font-size: 12px; opacity: 0; pointer-events: none; transform: translate(-50%, 18px); transition: opacity .2s, transform .2s; }
.toast.is-visible { opacity: 1; transform: translate(-50%, 0); }

@media (max-width: 1080px) {
  .nav-cta { display: none; }
  .site-nav a { padding-inline: 9px; }
  .course-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-main { grid-template-columns: 1.4fr repeat(3, .7fr); gap: 28px; }
}

@media (max-width: 820px) {
  .nav-shell { min-height: 66px; padding-inline: 18px; }
  .menu-button { display: block; }
  .site-nav { position: absolute; left: 14px; right: 14px; top: calc(100% + 8px); margin: 0; padding: 10px; display: none; border: 1px solid var(--line); border-radius: 14px; background: rgba(9,20,16,.98); box-shadow: var(--shadow); }
  .site-nav.is-open { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .site-nav a { padding: 12px; }
  .hero { min-height: auto; padding-top: 64px; grid-template-columns: 1fr; }
  .hero-visual { width: min(620px, 92%); margin: 0 auto; transform: none; }
  .safety-strip { margin-inline: 18px; }
  .learning-path, .source-note { grid-template-columns: 1fr; }
  .footer-main { grid-template-columns: 1.4fr 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 600px) {
  html { scroll-padding-top: 76px; }
  .brand small { display: none; }
  .hero { padding: 52px 18px 54px; }
  h1 { font-size: clamp(40px, 12vw, 55px); }
  .hero-lead { font-size: 15px; }
  .hero-actions .button { width: 100%; }
  .trust-points { gap: 10px; }
  .hero-visual { width: 100%; }
  .safety-strip { grid-template-columns: auto 1fr; padding: 15px; }
  .safety-strip a { grid-column: 2; }
  .library { padding: 78px 18px 60px; }
  .section-heading { align-items: start; }
  .result-count { display: none; }
  .library-tools { grid-template-columns: 1fr; }
  .bookmark-filter { justify-content: center; }
  kbd { display: none; }
  .filter-row { flex-wrap: nowrap; overflow-x: auto; padding-bottom: 5px; scrollbar-width: none; }
  .filter-row::-webkit-scrollbar { display: none; }
  .filter-chip { flex: 0 0 auto; }
  .course-grid { grid-template-columns: 1fr; }
  .course-body { min-height: auto; }
  .learning-path { margin-top: 12px; padding: 58px 18px; }
  .source-note { margin: 0 18px 70px; padding: 30px 20px; }
  .footer-main { padding-inline: 18px; grid-template-columns: repeat(2, 1fr); }
  .footer-brand { grid-column: 1 / -1; }
  .footer-bottom { padding-inline: 18px; flex-direction: column; }
  .dialog-content { padding: 20px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; animation-iteration-count: 1 !important; }
}