:root {
  --ink: #172025;
  --muted: #637178;
  --line: #dbe3e3;
  --paper: #f7faf9;
  --white: #ffffff;
  --mint: #0f8f83;
  --mint-dark: #0a625b;
  --mint-soft: #dff3ed;
  --coral: #f47b5b;
  --coral-soft: #fff0ea;
  --graphite: #273239;
  --shadow: 0 18px 50px rgba(26, 47, 50, .08);
  --radius: 8px;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--paper); line-height: 1.65; }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
.container { width: min(1160px, calc(100% - 40px)); margin: 0 auto; }

.site-header { position: sticky; top: 0; z-index: 20; background: rgba(247,250,249,.92); backdrop-filter: blur(14px); border-bottom: 1px solid rgba(219,227,227,.9); }
.nav-wrap { min-height: 72px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.brand { display: inline-flex; align-items: center; gap: 11px; font-weight: 800; letter-spacing: .02em; }
.brand-mark { width: 35px; height: 35px; border-radius: 10px; background: var(--ink); display: grid; place-items: center; position: relative; overflow: hidden; }
.brand-mark::before, .brand-mark::after { content: ""; position: absolute; width: 19px; height: 5px; border-radius: 4px; background: var(--mint); transform: rotate(-35deg); }
.brand-mark::before { top: 10px; left: 5px; box-shadow: 7px 8px 0 var(--coral); }
.brand-mark::after { width: 5px; height: 22px; top: 6px; left: 21px; background: #eaf7f2; transform: rotate(12deg); }
.brand-name { font-size: 18px; }
.brand-name small { display: block; font-size: 10px; color: var(--muted); font-weight: 600; letter-spacing: .15em; text-transform: uppercase; line-height: 1; margin-top: 2px; }
.nav-links { display: flex; align-items: center; gap: 24px; font-size: 14px; color: var(--muted); }
.nav-links a { padding: 7px 0; border-bottom: 2px solid transparent; }
.nav-links a:hover, .nav-links a[aria-current="page"] { color: var(--mint-dark); border-bottom-color: var(--mint); }
.menu-toggle { display: none; border: 0; background: transparent; font-size: 25px; cursor: pointer; color: var(--ink); }

.hero { padding: 72px 0 52px; }
.hero-grid { display: grid; grid-template-columns: 1.04fr .96fr; align-items: center; gap: 70px; }
.eyebrow { display: inline-flex; align-items: center; gap: 8px; font-size: 12px; color: var(--mint-dark); font-weight: 800; text-transform: uppercase; letter-spacing: .14em; }
.eyebrow::before { content: ""; width: 22px; height: 2px; background: var(--coral); }
h1, h2, h3 { margin: 0; line-height: 1.18; letter-spacing: -.02em; }
h1 { font-size: clamp(38px, 5.5vw, 68px); max-width: 650px; margin: 16px 0 20px; }
.hero-copy { font-size: 18px; color: var(--muted); max-width: 570px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.btn { min-height: 44px; display: inline-flex; align-items: center; justify-content: center; gap: 9px; border-radius: 6px; padding: 0 18px; font-weight: 750; font-size: 14px; border: 1px solid transparent; transition: transform .2s ease, box-shadow .2s ease, background .2s ease; }
.btn:hover { transform: translateY(-2px); box-shadow: 0 10px 25px rgba(15,143,131,.16); }
.btn-primary { color: #fff; background: var(--mint); }
.btn-secondary { color: var(--ink); background: var(--white); border-color: var(--line); }
.btn-coral { color: #552317; background: var(--coral-soft); border-color: #ffd1c3; }

.hero-visual { min-height: 390px; position: relative; display: grid; place-items: center; }
.device-scene { width: min(100%, 440px); aspect-ratio: 1 / .9; border: 1px solid #d8e8e4; border-radius: 28px; background: #edf7f4; position: relative; overflow: hidden; box-shadow: var(--shadow); }
.device-scene::before { content: ""; position: absolute; inset: 18px; border: 1px solid #c7dfd8; border-radius: 20px; }
.device-card { position: absolute; background: var(--white); border: 1px solid #dfe9e7; border-radius: 13px; box-shadow: 0 12px 30px rgba(31,59,61,.12); }
.device-main { width: 220px; height: 280px; left: 50%; top: 50%; transform: translate(-50%,-48%) rotate(-4deg); padding: 18px; }
.device-main .notch { width: 58px; height: 8px; border-radius: 10px; background: #d6e2e1; margin: 0 auto 22px; }
.device-main .screen-title { font-size: 11px; color: var(--muted); }
.ladder-bars { margin-top: 21px; display: grid; gap: 14px; }
.ladder-bars span { height: 11px; border-radius: 10px; background: #d8efea; position: relative; }
.ladder-bars span::after { content: ""; position: absolute; width: 45%; height: 100%; left: 0; top: 0; border-radius: inherit; background: var(--mint); }
.ladder-bars span:nth-child(2)::after { width: 72%; background: var(--coral); }
.ladder-bars span:nth-child(3)::after { width: 58%; background: var(--ink); }
.device-float { padding: 14px 16px; font-size: 12px; color: var(--muted); }
.device-float strong { display: block; color: var(--ink); font-size: 18px; margin-top: 2px; }
.float-a { top: 46px; left: 22px; transform: rotate(-6deg); }
.float-b { right: 17px; bottom: 35px; transform: rotate(5deg); }

.section { padding: 72px 0; }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 20px; margin-bottom: 28px; }
.section-kicker { color: var(--mint-dark); font-size: 12px; letter-spacing: .13em; text-transform: uppercase; font-weight: 800; }
.section h2 { font-size: clamp(28px, 4vw, 42px); margin-top: 7px; }
.section-lede { color: var(--muted); max-width: 500px; margin: 7px 0 0; }
.text-link { color: var(--mint-dark); font-weight: 750; font-size: 14px; white-space: nowrap; }
.text-link::after { content: " →"; color: var(--coral); }

.system-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
.system-card { border-radius: var(--radius); padding: 30px; min-height: 230px; position: relative; overflow: hidden; }
.system-card h3 { font-size: 28px; margin: 18px 0 9px; }
.system-card p { margin: 0; max-width: 380px; color: var(--muted); }
.system-card .system-icon { width: 45px; height: 45px; border-radius: 13px; display: grid; place-items: center; font-weight: 900; font-size: 19px; }
.system-card.ios { background: #e8f4f1; border: 1px solid #c9e6df; }
.system-card.ios .system-icon { background: var(--white); color: var(--mint-dark); }
.system-card.android { background: var(--graphite); color: #f2f7f5; }
.system-card.android p { color: #bdccca; }
.system-card.android .system-icon { background: var(--mint); color: #fff; }
.system-card::after { content: ""; position: absolute; right: -45px; bottom: -70px; width: 180px; height: 180px; border: 28px solid rgba(255,255,255,.42); border-radius: 50%; }

.feature-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 18px; }
.feature { background: var(--white); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; }
.feature .number { color: var(--coral); font-size: 12px; font-weight: 850; letter-spacing: .12em; }
.feature h3 { font-size: 21px; margin: 14px 0 8px; }
.feature p { margin: 0; color: var(--muted); font-size: 14px; }

.content-split { display: grid; grid-template-columns: 1.1fr .9fr; gap: 52px; align-items: start; }
.article-list { display: grid; gap: 0; border-top: 1px solid var(--line); }
.article-item { padding: 19px 0; border-bottom: 1px solid var(--line); display: grid; grid-template-columns: 92px 1fr auto; gap: 18px; align-items: start; }
.article-item time { font-size: 12px; color: var(--muted); padding-top: 4px; }
.article-item h3 { font-size: 18px; }
.article-item p { margin: 6px 0 0; color: var(--muted); font-size: 14px; }
.tag { display: inline-flex; align-items: center; min-height: 24px; padding: 0 9px; border-radius: 99px; background: var(--mint-soft); color: var(--mint-dark); font-size: 11px; font-weight: 800; white-space: nowrap; }
.guide-panel { background: var(--ink); color: #f4f8f6; border-radius: var(--radius); padding: 30px; position: sticky; top: 100px; }
.guide-panel p { color: #b7c6c4; }
.guide-steps { display: grid; gap: 17px; margin: 24px 0; }
.guide-step { display: grid; grid-template-columns: 29px 1fr; gap: 12px; align-items: start; }
.guide-step b { width: 29px; height: 29px; border: 1px solid #526665; border-radius: 50%; display: grid; place-items: center; color: #9ee1d3; font-size: 12px; }
.guide-step strong { font-size: 14px; display: block; }
.guide-step span { color: #aab9b7; font-size: 13px; }

.faq { display: grid; gap: 10px; max-width: 820px; }
details { background: var(--white); border: 1px solid var(--line); border-radius: 7px; padding: 0 18px; }
summary { list-style: none; cursor: pointer; padding: 18px 0; font-weight: 750; display: flex; align-items: center; justify-content: space-between; gap: 14px; }
summary::-webkit-details-marker { display: none; }
summary::after { content: "+"; color: var(--mint); font-size: 22px; font-weight: 400; }
details[open] summary::after { content: "−"; }
details p { color: var(--muted); margin: 0 0 18px; font-size: 14px; }

.page-hero { padding: 54px 0 40px; border-bottom: 1px solid var(--line); }
.page-hero h1 { font-size: clamp(36px, 5vw, 58px); max-width: 800px; }
.breadcrumb { color: var(--muted); font-size: 13px; margin-bottom: 18px; }
.breadcrumb a { color: var(--mint-dark); }
.topic-layout { display: grid; grid-template-columns: 1fr 320px; gap: 44px; align-items: start; }
.topic-intro { font-size: 17px; color: var(--muted); max-width: 750px; }
.topic-links { display: grid; gap: 10px; margin-top: 24px; }
.topic-link { background: var(--white); border: 1px solid var(--line); border-radius: 7px; padding: 16px 18px; display: flex; justify-content: space-between; gap: 12px; align-items: center; }
.topic-link span { color: var(--muted); font-size: 13px; }
.topic-aside { background: var(--mint-soft); border: 1px solid #c4e5dc; border-radius: var(--radius); padding: 23px; }
.topic-aside h2 { font-size: 20px; }
.topic-aside ul { margin: 16px 0 0; padding-left: 17px; color: var(--muted); font-size: 14px; }

.article-layout { display: grid; grid-template-columns: minmax(0, 1fr) 260px; gap: 55px; }
.article-body { background: var(--white); border: 1px solid var(--line); border-radius: var(--radius); padding: clamp(24px, 4vw, 48px); }
.article-body h1 { font-size: clamp(31px, 4vw, 48px); margin: 10px 0 16px; }
.article-meta { color: var(--muted); font-size: 13px; display: flex; flex-wrap: wrap; gap: 12px; align-items: center; padding-bottom: 22px; border-bottom: 1px solid var(--line); }
.article-lede { font-size: 19px; color: var(--muted); margin: 27px 0; }
.article-body h2 { font-size: 27px; margin: 34px 0 12px; }
.article-body h3 { font-size: 19px; margin: 24px 0 8px; }
.article-body p, .article-body li { color: #435359; }
.article-body ul { padding-left: 22px; }
.article-side { position: sticky; top: 100px; }
.side-box { border-top: 3px solid var(--mint); padding: 16px 0; margin-bottom: 20px; }
.side-box h2 { font-size: 16px; }
.side-box ul { list-style: none; margin: 13px 0 0; padding: 0; display: grid; gap: 9px; color: var(--muted); font-size: 14px; }
.article-nav { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 28px; }
.article-nav a { border: 1px solid var(--line); background: var(--paper); border-radius: 6px; padding: 13px; font-size: 13px; }
.article-nav small { color: var(--muted); display: block; margin-bottom: 4px; }

.site-footer { margin-top: 65px; border-top: 1px solid var(--line); padding: 35px 0 25px; color: var(--muted); font-size: 13px; }
.footer-grid { display: flex; justify-content: space-between; gap: 25px; align-items: start; }
.footer-links { display: flex; flex-wrap: wrap; gap: 16px; }
.footer-links a:hover { color: var(--mint-dark); }

@media (max-width: 860px) {
  .container { width: min(100% - 32px, 680px); }
  .menu-toggle { display: block; }
  .nav-links { display: none; position: absolute; top: 72px; left: 0; right: 0; background: var(--paper); border-bottom: 1px solid var(--line); padding: 12px 16px 20px; flex-direction: column; align-items: stretch; gap: 2px; }
  .nav-links.is-open { display: flex; }
  .nav-links a { padding: 11px 4px; }
  .hero { padding-top: 45px; }
  .hero-grid, .content-split, .topic-layout, .article-layout { grid-template-columns: 1fr; gap: 34px; }
  .hero-visual { order: -1; min-height: 300px; }
  .device-scene { width: min(100%, 440px); }
  .guide-panel, .article-side { position: static; }
  .feature-grid { grid-template-columns: 1fr; }
  .article-item { grid-template-columns: 72px 1fr; }
  .article-item .tag { grid-column: 2; justify-self: start; }
}
@media (max-width: 520px) {
  .container { width: min(100% - 24px, 480px); }
  .hero { padding-bottom: 30px; }
  h1 { font-size: 39px; }
  .hero-copy { font-size: 16px; }
  .section { padding: 54px 0; }
  .section-head { display: block; }
  .section-head .text-link { display: inline-block; margin-top: 14px; }
  .system-grid { grid-template-columns: 1fr; }
  .system-card { min-height: 205px; padding: 24px; }
  .device-scene { aspect-ratio: 1 / 1; }
  .device-main { transform: translate(-50%,-47%) rotate(-4deg) scale(.88); }
  .float-a { left: 8px; top: 28px; transform: scale(.86) rotate(-6deg); }
  .float-b { right: 3px; bottom: 24px; transform: scale(.86) rotate(5deg); }
  .footer-grid { display: grid; }
  .article-nav { grid-template-columns: 1fr; }
}

/* Neon / dark-gold visual refresh */
:root {
  --ink: #f2f0e8;
  --muted: #a5a8aa;
  --line: #2d3338;
  --paper: #090b0e;
  --white: #11161a;
  --mint: #b7f34a;
  --mint-dark: #d5ff70;
  --mint-soft: #1a261b;
  --coral: #ffb347;
  --coral-soft: #2b1e10;
  --graphite: #12181d;
  --shadow: 0 24px 70px rgba(0,0,0,.38);
}

body { background: var(--paper); color: var(--ink); }
.site-header { background: rgba(9,11,14,.88); border-bottom-color: #252b2f; }
.brand-mark { background: #0d1013; border: 1px solid #3e474a; }
.brand-mark::before { background: var(--mint); box-shadow: 7px 8px 0 var(--coral); }
.brand-mark::after { background: #f6e8bc; }
.brand-name small, .nav-links, .hero-copy, .section-lede, .system-card p, .article-item p, .topic-intro, .topic-link span, .article-body p, .article-body li, .site-footer { color: var(--muted); }
.nav-links a:hover, .nav-links a[aria-current="page"], .text-link, .breadcrumb a { color: var(--mint); }
.nav-links a:hover, .nav-links a[aria-current="page"] { border-bottom-color: var(--mint); }
.eyebrow, .section-kicker { color: var(--mint); }
.eyebrow::before { background: var(--coral); }

.hero { padding: 54px 0 78px; position: relative; isolation: isolate; background-image: url('../images/tech-circuit.jpg'); background-size: cover; background-position: center; border-bottom: 1px solid #30363b; }
.hero::before { content: ""; position: absolute; inset: 0; background: rgba(8,10,12,.78); z-index: -1; }
.hero::after { content: ""; position: absolute; inset: auto 0 0; height: 1px; background: var(--mint); box-shadow: 0 0 18px var(--mint); opacity: .75; }
.hero-grid { grid-template-columns: 1.12fr .88fr; gap: 44px; }
.hero h1 { text-shadow: 0 0 26px rgba(183,243,74,.12); }
.hero h1 span { color: var(--mint) !important; }
.hero-actions .btn-primary { background: var(--mint); color: #11170c; box-shadow: 0 0 24px rgba(183,243,74,.18); }
.hero-actions .btn-secondary { background: rgba(16,21,24,.76); color: var(--ink); border-color: #51595a; }
.hero-actions .btn:hover { box-shadow: 0 0 30px rgba(183,243,74,.22); }
.hero-meta { display: flex; flex-wrap: wrap; gap: 20px; margin-top: 31px; padding-top: 19px; border-top: 1px solid rgba(255,255,255,.16); color: #aeb6b5; font-size: 12px; }
.hero-meta span { display: inline-flex; align-items: baseline; gap: 7px; }
.hero-meta b { color: var(--mint); font-size: 21px; line-height: 1; }
.signal-strip { background: #0d1215; border-top: 1px solid #283236; border-bottom: 1px solid #283236; }
.signal-grid { min-height: 62px; display: grid; grid-template-columns: 1fr 1fr auto; align-items: center; gap: 24px; font-size: 12px; color: #a5aeae; }
.signal-grid > div { display: flex; align-items: center; gap: 10px; }
.signal-grid strong { color: #eff4ea; font-size: 12px; }
.signal-grid a { color: var(--mint); font-weight: 750; white-space: nowrap; }
.signal-grid a span { color: var(--coral); }
.signal-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--mint); box-shadow: 0 0 12px var(--mint); }
.hero-visual { min-height: 410px; }
.device-scene { background: rgba(16,22,25,.82); border-color: #4c5d5c; box-shadow: 0 0 0 1px rgba(183,243,74,.15), 0 28px 65px rgba(0,0,0,.5); }
.device-scene::before { border-color: #3d4d4c; }
.device-card { background: #12191c; border-color: #3f4c4d; box-shadow: 0 18px 35px rgba(0,0,0,.4); }
.device-main .notch { background: #4b5453; }
.device-main .screen-title, .device-float, .device-float strong, .device-main div[style*="color:var(--muted)"] { color: var(--muted) !important; }
.device-main div[style*="font-size:31px"] { color: var(--mint) !important; }
.ladder-bars span { background: #24322b; }
.ladder-bars span::after { background: var(--mint); box-shadow: 0 0 10px rgba(183,243,74,.32); }
.ladder-bars span:nth-child(2)::after { background: var(--coral); }
.ladder-bars span:nth-child(3)::after { background: #f4e2a7; }

.section { background: var(--paper); }
.section[style*="background:#eef4f2"] { background: #0e1317 !important; border-top: 1px solid #20282c; border-bottom: 1px solid #20282c; }
.system-grid { grid-template-columns: 1.15fr .85fr; gap: 14px; }
.system-card { border-radius: 3px; min-height: 255px; border: 1px solid #3d494a !important; }
.system-card.ios { background: #121d1b; }
.system-card.android { background: #171a1d; }
.system-card .system-icon { background: #1c2525 !important; color: var(--mint) !important; border: 1px solid #495550; }
.system-card.android .system-icon { background: var(--coral) !important; color: #21160d !important; border-color: var(--coral); }
.system-card::after { border-color: rgba(183,243,74,.1); }
.feature { background: #11161a; border-color: #2d373b; border-radius: 3px; }
.feature .number { color: var(--coral); }
.article-list { border-top-color: #2d373b; }
.article-item { border-bottom-color: #2d373b; }
.tag { background: #25311e; color: var(--mint); border: 1px solid #445d32; }
.guide-panel { background: #161d1f; border: 1px solid #48524d; border-radius: 3px; box-shadow: var(--shadow); }
.guide-panel p, .guide-step span { color: #aeb9b0; }
.guide-step b { border-color: #52625a; color: var(--mint); }
.btn-coral { color: #1b1208; background: var(--coral); border-color: var(--coral); }

details, .topic-link, .article-body, .article-nav a { background: #11161a; border-color: #2d373b; border-radius: 3px; }
summary::after { color: var(--mint); }
.page-hero { background-color: #0d1215; background-image: url('../images/tech-circuit.jpg'); background-size: cover; background-position: center 45%; position: relative; isolation: isolate; border-bottom-color: #2b3437; }
.page-hero::before { content: ""; position: absolute; inset: 0; background: rgba(9,11,14,.84); z-index: -1; }
.topic-aside { background: #182219; border-color: #405638; }
.article-body { box-shadow: var(--shadow); }
.side-box { border-top-color: var(--mint); }
.site-footer { border-top-color: #2b3437; background: #080a0c; }
.footer-links a:hover { color: var(--mint); }

@media (max-width: 860px) {
  .nav-links { background: #0c1013; border-bottom-color: #2a3437; }
  .hero-grid { grid-template-columns: 1fr; }
  .hero-visual { order: -1; }
  .system-grid { grid-template-columns: 1fr; }
  .signal-grid { grid-template-columns: 1fr; gap: 9px; padding: 14px 0; }
  .signal-grid a { justify-self: start; }
}