/* JD AI home page (index.html) and the 词爱课 page (wordaike/). 成长护盾 keeps site.css; install, privacy, terms use style.css. */
:root {
  --ink: #0f1222;
  --body: #3b4256;
  --muted: #6b7288;
  --line: #e6e8f0;
  --bg: #f6f7fb;
  --blue: #2563eb;
  --blue-2: #60a5fa;
  --violet: #6d5df6;
  --purple: #a855f7;
  --pink: #ec4899;
  --aurora: linear-gradient(120deg, #5b4cf0 0%, #8b5cf6 45%, #d946ef 100%);
  --radius: 24px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; color: var(--body); background: #fff;
  font: 16px/1.75 -apple-system, BlinkMacSystemFont, "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", sans-serif;
  -webkit-text-size-adjust: 100%;
}
a { color: inherit; text-decoration: none; }
h1, h2, h3 { color: var(--ink); margin: 0; letter-spacing: -0.015em; line-height: 1.25; }
p { margin: 0; }
img { max-width: 100%; height: auto; display: block; }
.wrap { max-width: 1120px; margin: 0 auto; padding: 0 20px; }

/* nav */
.nav { position: sticky; top: 0; z-index: 20; background: rgba(255, 255, 255, 0.86); backdrop-filter: saturate(180%) blur(14px); -webkit-backdrop-filter: saturate(180%) blur(14px); border-bottom: 1px solid rgba(15, 18, 34, 0.06); }
.nav .wrap { display: flex; align-items: center; height: 64px; gap: 14px; }
.logo { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 19px; color: var(--ink); letter-spacing: 0.01em; }
.logo-mark { width: 30px; height: 30px; border-radius: 9px; background: linear-gradient(135deg, var(--blue) 0%, var(--violet) 55%, var(--pink) 100%); position: relative; box-shadow: 0 4px 12px rgba(109, 93, 246, 0.35); }
.logo-mark::after { content: ""; position: absolute; inset: 8px; border-radius: 50%; border: 3px solid rgba(255, 255, 255, 0.92); border-right-color: transparent; transform: rotate(-30deg); }
.crumb { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 17px; color: var(--ink); }
.crumb img { width: 32px; height: 32px; border-radius: 9px; }
.crumb-sep { color: #cfd3e0; font-size: 20px; }
.nav .links { display: flex; align-items: center; gap: 26px; margin-left: auto; font-size: 15px; }
.nav .links a { color: var(--body); }
.nav .links a:hover { color: var(--ink); }
/* buttons in the nav keep their white text (the plain-link colours above would otherwise win) */
.nav .links a.btn, .nav .links a.btn:hover { color: #fff; }
.nav .links a.btn:hover { box-shadow: 0 6px 16px rgba(15, 18, 34, 0.25); }

/* buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font-weight: 600; font-size: 16px; padding: 13px 24px; border-radius: 999px; border: 0; cursor: pointer;
  background: var(--ink); color: #fff; transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn.small { padding: 8px 16px; font-size: 14px; }
.btn.blue { background: var(--blue); box-shadow: 0 8px 22px rgba(37, 99, 235, 0.28); }
.btn.aurora { background: var(--aurora); box-shadow: 0 10px 26px rgba(139, 92, 246, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.35); }
.btn.line { background: transparent; color: var(--ink); box-shadow: inset 0 0 0 1.5px rgba(15, 18, 34, 0.14); }
.btn.line:hover { box-shadow: inset 0 0 0 1.5px rgba(15, 18, 34, 0.32); }
.btn.glass { background: rgba(255, 255, 255, 0.14); color: #fff; box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.28); }
.arrow::after { content: "→"; font-weight: 500; transition: transform 0.15s ease; }
.btn:hover .arrow::after, a:hover > .arrow::after { transform: translateX(3px); }

.tag { display: inline-flex; align-items: center; gap: 6px; font-size: 12.5px; font-weight: 700; padding: 3px 11px; border-radius: 999px; letter-spacing: 0.02em; }
.tag.live { color: #15803d; background: #dcfce7; }
.tag.live::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: #22c55e; box-shadow: 0 0 0 3px rgba(34, 197, 94, 0.2); }
.tag.soon { color: #7c3aed; background: #f1ebff; }
.tag.dark { color: #fff; background: rgba(255, 255, 255, 0.16); }

/* ---------- home: hero ---------- */
.home-hero { position: relative; overflow: hidden; background: #0b0d1c; color: #c9cee0; padding: 96px 0 120px; }
.home-hero::before, .home-hero::after { content: ""; position: absolute; border-radius: 50%; filter: blur(80px); opacity: 0.55; pointer-events: none; }
.home-hero::before { width: 560px; height: 560px; left: -140px; top: -180px; background: #2563eb; }
.home-hero::after { width: 620px; height: 620px; right: -180px; bottom: -320px; background: #a855f7; }
.home-hero .wrap { position: relative; z-index: 1; }
.home-hero .kicker { display: inline-block; font-size: 13px; font-weight: 700; letter-spacing: 0.18em; color: #9aa5ff; margin-bottom: 20px; }
.home-hero h1 { color: #fff; font-size: 54px; font-weight: 800; max-width: 900px; }
.home-hero h1 em { font-style: normal; background: linear-gradient(90deg, #93c5fd, #c4b5fd 50%, #f0abfc); -webkit-background-clip: text; background-clip: text; color: transparent; }
.home-hero .lead { font-size: 19px; max-width: 640px; margin-top: 22px; color: #b7bdd3; }
.home-hero .cta { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 34px; }
.home-hero .btn.white { background: #fff; color: var(--ink); }

/* ---------- home: products ---------- */
.products { margin-top: -64px; position: relative; z-index: 2; padding-bottom: 40px; }
.product-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.product {
  position: relative; overflow: hidden; border-radius: 28px; padding: 34px 34px 0; display: flex; flex-direction: column;
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.6) inset, 0 24px 60px -24px rgba(15, 18, 34, 0.35); 
}
.product.shield { background: linear-gradient(160deg, #eef4ff 0%, #ffffff 60%); }
.product.wordaike { background: linear-gradient(160deg, #f3efff 0%, #fdf4ff 55%, #ffffff 100%); }
.product .head { display: flex; align-items: center; gap: 14px; }
.product .head img { width: 56px; height: 56px; border-radius: 15px; box-shadow: 0 6px 16px rgba(15, 18, 34, 0.14); }
.product .head h2 { font-size: 26px; }
.product .head .sub { font-size: 14px; color: var(--muted); }
.product .pitch { font-size: 21px; font-weight: 700; color: var(--ink); margin-top: 22px; line-height: 1.45; }
.product ul { list-style: none; padding: 0; margin: 16px 0 0; display: grid; gap: 8px; font-size: 15px; }
.product li { position: relative; padding-left: 24px; }
.product li::before { content: ""; position: absolute; left: 2px; top: 9px; width: 12px; height: 12px; border-radius: 4px; }
.product.shield li::before { background: linear-gradient(135deg, #3b82f6, #60a5fa); }
.product.wordaike li::before { background: var(--aurora); }
.product .actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 24px; }
/* the picture peeks out of the card bottom: fixed height, cropped */
.product .stage { margin-top: auto; padding-top: 30px; height: 390px; overflow: hidden; display: flex; justify-content: center; align-items: flex-start; }
.product .stage .device { width: 56%; transition: transform 0.3s ease; }
.product:hover .stage .device { transform: translateY(-8px); }
.shield .stage img.photo { width: 74%; border-radius: 22px; box-shadow: 0 20px 50px -10px rgba(37, 99, 235, 0.3); transition: transform 0.3s ease; }
.product.shield:hover .stage img.photo { transform: translateY(-8px); }

/* phone frame around a screenshot (wordaike screenshots are bare screens) */
.device { position: relative; border-radius: 44px; padding: 10px; background: #12131c; box-shadow: 0 30px 60px -20px rgba(45, 30, 120, 0.45), 0 0 0 1px rgba(255, 255, 255, 0.06) inset; }
.device img { border-radius: 34px; width: 100%; }
.device::before { content: ""; position: absolute; top: 20px; left: 50%; width: 30%; height: 22px; margin-left: -15%; border-radius: 999px; background: #12131c; z-index: 1; }

/* ---------- home: principles ---------- */
.section { padding: 96px 0; }
.section.tint { background: var(--bg); }
.section-head { max-width: 680px; margin-bottom: 44px; }
.section-head .kicker { font-size: 13px; font-weight: 700; letter-spacing: 0.16em; color: var(--violet); }
.section-head h2 { font-size: 36px; margin-top: 10px; }
.section-head p { margin-top: 14px; font-size: 17px; color: var(--muted); }
.cards3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 28px; }
.card h3 { font-size: 19px; margin-top: 16px; }
.card p { font-size: 15px; margin-top: 8px; }
.card .glyph { width: 44px; height: 44px; border-radius: 13px; display: grid; place-items: center; color: #fff; }
.card .glyph svg { width: 22px; height: 22px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
.g-blue { background: linear-gradient(135deg, #2563eb, #60a5fa); }
.g-violet { background: linear-gradient(135deg, #6d5df6, #a78bfa); }
.g-pink { background: linear-gradient(135deg, #d946ef, #f472b6); }
.g-teal { background: linear-gradient(135deg, #0d9488, #2dd4bf); }
.g-amber { background: linear-gradient(135deg, #d97706, #fbbf24); }

.contact { display: flex; align-items: center; justify-content: space-between; gap: 24px; border-radius: 28px; padding: 40px 44px; background: #0b0d1c; color: #c9cee0; position: relative; overflow: hidden; }
.contact::after { content: ""; position: absolute; width: 380px; height: 380px; right: -100px; top: -160px; border-radius: 50%; background: #6d5df6; filter: blur(70px); opacity: 0.5; }
.contact > * { position: relative; z-index: 1; }
.contact h2 { color: #fff; font-size: 28px; }
.contact p { margin-top: 8px; }

/* ---------- wordaike page ---------- */
.w-hero { position: relative; overflow: hidden; padding: 72px 0 96px; background: #f7f4ff; }
.w-hero .glow { position: absolute; border-radius: 50%; filter: blur(70px); pointer-events: none; }
.w-hero .g1 { width: 520px; height: 520px; left: -160px; top: -200px; background: #c4b5fd; opacity: 0.8; }
.w-hero .g2 { width: 480px; height: 480px; right: -120px; top: 40px; background: #f9a8d4; opacity: 0.55; }
.w-hero .g3 { width: 420px; height: 420px; left: 30%; bottom: -260px; background: #93c5fd; opacity: 0.5; }
.w-hero .wrap { position: relative; z-index: 1; display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 48px; align-items: center; }
.w-hero h1 { font-size: 52px; font-weight: 800; margin-top: 18px; }
.w-hero h1 em { font-style: normal; background: var(--aurora); -webkit-background-clip: text; background-clip: text; color: transparent; }
.w-hero .lead { font-size: 18.5px; margin-top: 20px; max-width: 560px; }
.w-hero .cta { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 30px; }
.w-hero .fine { font-size: 14px; color: var(--muted); margin-top: 18px; }
.w-hero .device { width: 300px; margin: 0 auto; transform: rotate(3deg); }
.langs { display: flex; gap: 10px; margin-top: 26px; flex-wrap: wrap; }
.lang { display: flex; align-items: center; gap: 10px; background: rgba(255, 255, 255, 0.75); border: 1px solid rgba(255, 255, 255, 0.9); box-shadow: 0 6px 18px rgba(109, 93, 246, 0.12); padding: 8px 14px 8px 8px; border-radius: 16px; font-size: 14px; }
.lang b { display: grid; place-items: center; width: 34px; height: 34px; border-radius: 10px; color: #fff; font-size: 13px; letter-spacing: 0.02em; }
.lang .en { background: linear-gradient(135deg, #6d5df6, #a78bfa); }
.lang .de { background: linear-gradient(135deg, #db2777, #f472b6); }
.lang span { color: var(--ink); font-weight: 600; line-height: 1.3; }
.lang small { display: block; color: var(--muted); font-weight: 400; font-size: 12.5px; }

.feature-row { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center; }
.feature-row + .feature-row { margin-top: 110px; }
.feature-row.flip > :first-child { order: 2; }
.feature-row .device { width: 290px; margin: 0 auto; }
.feature-row h2 { font-size: 34px; margin-top: 12px; }
.feature-row h2 em { font-style: normal; background: var(--aurora); -webkit-background-clip: text; background-clip: text; color: transparent; }
.feature-row .lead { font-size: 17px; margin-top: 14px; }
.eyebrow { font-size: 13px; font-weight: 700; letter-spacing: 0.08em; color: var(--violet); }
.ticks { list-style: none; padding: 0; margin: 22px 0 0; display: grid; gap: 12px; }
.ticks li { display: grid; grid-template-columns: 26px 1fr; gap: 10px; font-size: 15.5px; }
.ticks li::before { content: "✓"; display: grid; place-items: center; width: 22px; height: 22px; margin-top: 3px; border-radius: 7px; background: #efe9ff; color: var(--violet); font-size: 13px; font-weight: 800; }
.ticks b { color: var(--ink); }

/* word card mock (the back of a review card in the app) */
.wordcard { max-width: 420px; margin: 0 auto; background: rgba(255, 255, 255, 0.92); border: 1px solid #ece8fb; border-radius: 28px; padding: 26px 26px 22px; box-shadow: 0 30px 70px -28px rgba(91, 76, 240, 0.45); position: relative; }
.wordcard::before { content: ""; position: absolute; inset: -40px -30px auto auto; width: 200px; height: 200px; border-radius: 50%; background: #f5d0fe; filter: blur(50px); opacity: 0.7; z-index: -1; }
.wc-top { display: flex; align-items: baseline; gap: 12px; }
.wc-word { font: 600 36px/1.1 "Source Serif 4", Georgia, "Times New Roman", serif; color: var(--ink); }
.wc-ipa { font: 17px Georgia, serif; color: var(--violet); white-space: nowrap; }
.wc-say { margin-left: auto; width: 34px; height: 34px; border-radius: 50%; background: var(--aurora); align-self: center; position: relative; }
.wc-say::after { content: ""; position: absolute; left: 13px; top: 11px; border: 6px solid transparent; border-left: 9px solid #fff; }
.wc-sum { margin-top: 12px; padding: 10px 14px; border-radius: 14px; background: #f4f1ff; color: var(--ink); font-weight: 600; font-size: 15px; }
.wc-sum i, .wordcard b { font-style: normal; }
.wc-sum i { color: var(--violet); margin-right: 2px; }
.wc-sense { margin-top: 16px; font-size: 14.5px; }
.wc-sense b { color: var(--ink); }
.wc-sense p { line-height: 1.6; color: var(--muted); }
.wc-sense p.en { color: var(--ink); font: 16px/1.55 Georgia, serif; margin-top: 4px; }
.wc-sense u { text-decoration: none; background: linear-gradient(transparent 62%, #e9d5ff 62%); }
.wc-note { margin-top: 14px; padding: 12px 14px; border-radius: 14px; background: #f6f7fb; font-size: 14px; }
.wc-note b { color: var(--ink); font-size: 13px; }
.wc-note p { margin-top: 2px; line-height: 1.6; }
.wc-note .src { color: var(--violet); font-size: 12.5px; margin-left: 6px; }
.wc-note.mn { background: #fdf2fa; }

/* study-stats mock (the app's 学习统计 page) */
.statcard { max-width: 420px; width: 100%; margin: 0 auto; background: #fff; border: 1px solid #ece8fb; border-radius: 28px; padding: 14px 14px 18px; box-shadow: 0 30px 70px -28px rgba(91, 76, 240, 0.45); position: relative; }
.statcard::before { content: ""; position: absolute; inset: auto auto -40px -30px; width: 200px; height: 200px; border-radius: 50%; background: #c7d2fe; filter: blur(50px); opacity: 0.7; z-index: -1; }
.sc-head { display: flex; align-items: center; gap: 12px; padding: 16px 18px; border-radius: 20px; background: var(--aurora); color: #fff; box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.35); }
.sc-flame { display: grid; place-items: center; width: 40px; height: 40px; border-radius: 12px; background: rgba(255, 255, 255, 0.18); }
.sc-flame svg { width: 24px; height: 24px; fill: #fbbf24; stroke: #fde68a; stroke-width: 1.8; stroke-linejoin: round; }
.sc-streak { font-size: 15px; font-weight: 600; line-height: 1.2; }
.sc-streak b { font-size: 30px; font-weight: 800; letter-spacing: -0.02em; margin-right: 2px; }
.sc-streak small, .sc-today small { display: block; font-size: 12.5px; font-weight: 500; opacity: 0.8; margin-top: 3px; }
.sc-today { margin-left: auto; text-align: right; line-height: 1.2; }
.sc-today b { font-size: 22px; font-weight: 800; }
.sc-block { padding: 16px 8px 0; }
.sc-title { display: flex; justify-content: space-between; gap: 8px; font-size: 13.5px; font-weight: 700; color: var(--ink); margin-bottom: 9px; }
.sc-title span { font-weight: 500; color: var(--muted); }
.heat { display: grid; grid-template-rows: repeat(7, 1fr); grid-auto-flow: column; grid-auto-columns: 1fr; gap: 3px; }
.heat i, .heat-key i { aspect-ratio: 1; border-radius: 2.5px; background: #efedf7; }
.heat .l1, .heat-key .l1 { background: rgba(109, 93, 246, 0.3); }
.heat .l2, .heat-key .l2 { background: rgba(109, 93, 246, 0.5); }
.heat .l3, .heat-key .l3 { background: rgba(109, 93, 246, 0.75); }
.heat .l4, .heat-key .l4 { background: #6d5df6; }
.heat-key { display: flex; align-items: center; justify-content: flex-end; gap: 3px; margin-top: 7px; font-size: 11.5px; color: var(--muted); }
.heat-key i { width: 9px; }
.heat-key i:first-of-type { margin-left: 4px; }
.heat-key i:last-of-type { margin-right: 4px; }
.bars { display: flex; align-items: flex-end; gap: 3px; height: 64px; border-bottom: 1px solid var(--line); }
.bars i { flex: 1; border-radius: 3px 3px 0 0; background: #a5b4fc; }
.bars i:first-child { background: #6d5df6; }
.sc-split { display: flex; align-items: center; gap: 16px; }
.ring { flex: none; width: 70px; height: 70px; border-radius: 50%; display: grid; place-items: center; background: conic-gradient(#6d5df6 calc(var(--p) * 1%), #efedf7 0); position: relative; }
.ring::before { content: ""; position: absolute; inset: 7px; border-radius: 50%; background: #fff; }
.ring b { position: relative; font-size: 17px; font-weight: 800; color: var(--ink); }
.sc-dist { flex: 1; min-width: 0; }
.seg { display: flex; gap: 2px; height: 10px; border-radius: 5px; overflow: hidden; }
.seg-key { display: flex; flex-wrap: wrap; gap: 4px 12px; margin-top: 9px; font-size: 12px; color: var(--body); line-height: 1.4; }
.seg-key span { display: inline-flex; align-items: center; gap: 5px; white-space: nowrap; }
.seg-key i { width: 8px; height: 8px; border-radius: 2px; }

.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.stat { background: #fff; border-radius: 22px; padding: 24px; border: 1px solid var(--line); }
.stat b { display: block; font-size: 34px; font-weight: 800; line-height: 1.1; background: var(--aurora); -webkit-background-clip: text; background-clip: text; color: transparent; }
.stat span { display: block; margin-top: 8px; font-size: 14.5px; color: var(--muted); }

.soon-box { text-align: center; border-radius: 32px; padding: 64px 28px; background: var(--aurora); color: rgba(255, 255, 255, 0.86); position: relative; overflow: hidden; }
.soon-box::before { content: ""; position: absolute; inset: 0; background: radial-gradient(circle at 20% 0%, rgba(255, 255, 255, 0.35), transparent 45%); }
.soon-box > * { position: relative; }
.soon-box img { width: 76px; height: 76px; border-radius: 20px; margin: 0 auto; box-shadow: 0 12px 30px rgba(40, 10, 90, 0.35); }
.soon-box h2 { color: #fff; font-size: 34px; margin-top: 22px; }
.soon-box p { margin: 12px auto 0; max-width: 560px; font-size: 16.5px; }
.soon-box .cta { display: flex; justify-content: center; gap: 12px; flex-wrap: wrap; margin-top: 28px; }

/* footer */
footer { padding: 34px 0 44px; font-size: 14px; color: var(--muted); border-top: 1px solid var(--line); }
footer .wrap { display: flex; flex-wrap: wrap; gap: 10px 22px; align-items: center; }
footer a:hover { color: var(--ink); }
footer .right { margin-left: auto; }

@media (max-width: 900px) {
  .nav .links a:not(.btn) { display: none; }
  .home-hero { padding: 64px 0 104px; }
  .home-hero h1 { font-size: 36px; }
  .home-hero .lead { font-size: 16.5px; }
  .product-grid, .cards3 { grid-template-columns: 1fr; }
  .product { padding: 26px 22px 0; min-height: 0; }
  .product .stage { height: 320px; }
  .product .pitch { font-size: 19px; }
  .product .stage .device { width: 70%; }
  .section { padding: 64px 0; }
  .section-head h2 { font-size: 28px; }
  .contact { flex-direction: column; align-items: flex-start; padding: 30px 24px; }
  .w-hero { padding: 48px 0 64px; }
  .w-hero .wrap, .feature-row { grid-template-columns: 1fr; gap: 40px; }
  .feature-row.flip > :first-child { order: 0; }
  .feature-row + .feature-row { margin-top: 72px; }
  .w-hero h1 { font-size: 36px; }
  .w-hero .device { width: 250px; }
  .feature-row .device { width: 250px; }
  .feature-row h2, .soon-box h2 { font-size: 27px; }
  .stats { grid-template-columns: 1fr 1fr; }
  .stat b { font-size: 28px; }
  .wc-word { font-size: 30px; }
  .wordcard { padding: 22px 20px 18px; }
  .statcard { padding: 10px 10px 16px; border-radius: 24px; }
  .sc-head { padding: 14px; }
  .heat { gap: 2px; }
  footer .right { margin-left: 0; }
}