/* 设计方向：牙科诊室的干净 + 菌斑显示剂的紫色。
   主色从 Brushmo 绿调成更偏临床的青绿；紫色只用来表示牙菌斑。 */
:root {
  --accent: #1f7a64;
  --accent-dark: #145a49;
  --accent-soft: #e4f1ec;
  --mint: #7fd1b9;
  --plaque: #7b4dd8;
  --plaque-soft: #efe8fc;
  --gum: #f3d3cf;
  --text: #0f2a2e;
  --text-2: #4f6366;
  --bg: #f6f8f7;
  --card: #ffffff;
  --line: #dfe7e4;
  --font-display: "Bricolage Grotesque", "Hanken Grotesk", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, Menlo, monospace;
  --good: #44974d;
  --fair: #f0b429;
  --attention: #e07a3f;
  --risk: #c64747;
  --radius: 20px;
  --max: 1120px;
  font-family: "Hanken Grotesk", system-ui, -apple-system, "Segoe UI", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

* { box-sizing: border-box; }
body { margin: 0; }
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
h1, h2, h3 { font-family: var(--font-display); font-weight: 600; line-height: 1.1; margin: 0; letter-spacing: -0.025em; }
h3 { letter-spacing: -0.01em; }
a:focus-visible, summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 6px; }
p { margin: 0; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 24px; }
section { padding: 96px 0; }
.eyebrow { font-family: var(--font-mono); color: var(--accent); font-weight: 500; font-size: 12px; letter-spacing: 0.12em; text-transform: uppercase; }
.section-head { max-width: 640px; margin-bottom: 48px; }
.section-head h2 { font-size: clamp(28px, 4vw, 40px); margin: 8px 0 12px; }
.section-head p { color: var(--text-2); font-size: 17px; }
.center { text-align: center; margin-left: auto; margin-right: auto; }

.btn { display: inline-flex; align-items: center; gap: 8px; padding: 14px 24px; border-radius: 999px; font-weight: 600; font-size: 16px; transition: transform .15s, background .15s; }
.btn:hover { transform: translateY(-1px); }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-dark); }
.btn-ghost { background: var(--card); border: 1px solid var(--line); }

/* 导航 */
.nav { position: sticky; top: 0; z-index: 10; background: rgba(249, 251, 250, .85); backdrop-filter: blur(12px); border-bottom: 1px solid var(--line); }
.nav .wrap { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.logo { font-family: var(--font-display); display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 18px; }
.logo-mark { width: 36px; height: 36px; }
.nav-links { display: flex; gap: 28px; color: var(--text-2); font-size: 15px; }
.nav-links a:hover { color: var(--text); }
.nav .btn { padding: 9px 18px; font-size: 14px; }

/* 首屏 */
.hero { padding: 80px 0 96px; background: radial-gradient(1000px 500px at 85% 10%, var(--accent-soft), transparent 70%); }
.hero .wrap { display: grid; grid-template-columns: 1.1fr 1fr; gap: 56px; align-items: center; }
.hero h1 { font-size: clamp(42px, 6vw, 72px); font-weight: 700; margin: 16px 0 24px; }
/* 签名元素：像菌斑显示剂一样把 "missed" 染成紫色 */
.hero h1 em { font-style: normal; color: var(--plaque); background: linear-gradient(transparent 62%, var(--plaque-soft) 62%); padding: 0 .06em; }
.hero-lead { font-size: 19px; color: var(--text-2); max-width: 520px; }
.hero-cta { display: flex; gap: 12px; margin-top: 32px; flex-wrap: wrap; }
.hero-note { margin-top: 20px; font-size: 14px; color: var(--text-2); }

/* iPhone 外观：钛金属边框 + 黑色屏幕边 + 灵动岛 + 侧键 */
.phone {
  position: relative; justify-self: center; width: 300px; aspect-ratio: 9 / 19.5;
  padding: 11px; border-radius: 54px;
  background: linear-gradient(145deg, #e9ece9, #9aa19c 30%, #d8dcd9 55%, #7d847f 80%, #c9cdca);
  box-shadow: 0 40px 80px rgba(31, 45, 36, .22), 0 8px 20px rgba(31, 45, 36, .12), inset 0 0 0 1px rgba(255, 255, 255, .5);
}
.phone::before { content: ""; position: absolute; inset: 3px; border-radius: 51px; background: #0b0d0c; }
.btn-side { position: absolute; width: 4px; border-radius: 2px; background: linear-gradient(90deg, #7d847f, #c9cdca); }
.btn-action { left: -3px; top: 104px; height: 26px; }
.btn-vol-up { left: -3px; top: 150px; height: 50px; }
.btn-vol-down { left: -3px; top: 212px; height: 50px; }
.btn-power { right: -3px; top: 170px; height: 80px; }
.screen { position: relative; height: 100%; border-radius: 44px; background: var(--card); padding: 14px 20px 28px; overflow: hidden; }
.status-bar { display: flex; align-items: center; justify-content: space-between; height: 34px; padding: 0 8px; margin-bottom: 18px; font-size: 14px; font-weight: 600; color: var(--text); }
.status-bar .time { width: 54px; text-align: center; }
.island { width: 96px; height: 28px; border-radius: 16px; background: #0b0d0c; }
.status-icons { display: flex; gap: 5px; align-items: center; fill: currentColor; }
.tip { margin-top: 14px; padding: 12px; border-radius: 12px; background: var(--accent-soft); font-size: 12px; line-height: 1.45; color: var(--text); }
.tip b { color: var(--accent); margin-right: 4px; }
.tab-bar { position: absolute; left: 0; right: 0; bottom: 0; display: flex; justify-content: space-around; padding: 10px 16px 24px; border-top: 1px solid var(--line); background: rgba(255, 255, 255, .92); }
.tab { display: grid; justify-items: center; gap: 4px; font-size: 10px; font-weight: 500; color: #a3ada7; }
.tab i { width: 20px; height: 20px; border-radius: 6px; background: currentColor; opacity: .5; }
.tab.active { color: var(--accent); }
.tab.active i { opacity: 1; }
.home-indicator { position: absolute; left: 50%; bottom: 8px; transform: translateX(-50%); width: 110px; height: 5px; border-radius: 3px; background: var(--text); }
.screen-title { font-size: 13px; color: var(--text-2); text-align: center; }
.ring { position: relative; width: 180px; height: 180px; margin: 16px auto; }
.ring svg { transform: rotate(-90deg); }
.ring-value { position: absolute; inset: 0; display: grid; place-content: center; text-align: center; }
.ring-value strong { font-family: var(--font-display); font-weight: 700; font-size: 52px; line-height: 1; letter-spacing: -0.03em; }
.ring-value span { font-size: 13px; color: var(--good); font-weight: 600; }
.zones { display: grid; gap: 10px; margin-top: 8px; }
.zone { display: flex; gap: 8px; justify-content: space-between; align-items: center; font-size: 13px; padding: 10px 12px; border-radius: 12px; background: var(--bg); }
.zone b { font-weight: 600; flex: 1; }
.zone span { white-space: nowrap; }
.bar { flex: 0 0 72px; height: 6px; border-radius: 3px; background: var(--line); overflow: hidden; margin-left: 10px; }
.bar i { display: block; height: 100%; border-radius: 3px; }

/* 步骤 */
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 32px; }
.step-num { width: 40px; height: 40px; border-radius: 12px; background: var(--accent-soft); color: var(--accent); font-family: var(--font-mono); font-weight: 500; display: grid; place-items: center; margin-bottom: 20px; }
.card h3 { font-size: 20px; margin-bottom: 10px; }
.card p { color: var(--text-2); }

/* Brush Number 等级 */
.score-section { background: var(--card); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.levels { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.level { border-radius: var(--radius); padding: 24px; background: var(--bg); border-top: 4px solid var(--c); }
.level .range { font-family: var(--font-mono); font-size: 22px; font-weight: 500; color: var(--c); }
.level h3 { font-size: 17px; margin: 6px 0 8px; }
.level p { font-size: 14px; color: var(--text-2); }
.pga { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 40px; }
.pga .card { padding: 24px; }
.pga .tag { display: inline-block; font-weight: 700; color: var(--accent); background: var(--accent-soft); border-radius: 8px; padding: 2px 10px; margin-bottom: 10px; }

/* 三个区域 */
.regions { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.region-list { display: grid; gap: 16px; }
.region { display: flex; gap: 16px; align-items: flex-start; }
.dot { flex: 0 0 14px; height: 14px; border-radius: 50%; margin-top: 6px; }
.region h3 { font-size: 18px; margin-bottom: 4px; }
.region p { color: var(--text-2); }
/* 牙位图 */
.chart { margin: 0; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px 28px 20px; }
.chart-head { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 6px 12px; font-family: var(--font-mono); font-size: 11px; letter-spacing: .08em; text-transform: uppercase; color: var(--text-2); }
.legend { display: inline-flex; align-items: center; gap: 6px; white-space: nowrap; }
.legend i { width: 10px; height: 10px; border-radius: 3px; background: var(--plaque); }
.arch { margin: 12px auto 4px; overflow: visible; }
.arch .gum { fill: none; stroke: var(--gum); stroke-width: 34; stroke-linecap: round; }
.arch .tooth rect { fill: #fff; stroke: #c9d6d2; stroke-width: 1.5; }
.arch .plaque { fill: var(--plaque); opacity: .8; stroke: none; }
.arch path.plaque { fill: none; stroke: var(--plaque); stroke-width: 5; stroke-linecap: round; }
.arch text { font-family: var(--font-mono); font-size: 10px; fill: #8aa09b; text-anchor: middle; }
.chart-foot { font-size: 13px; color: var(--text-2); text-align: center; }
@media (prefers-reduced-motion: no-preference) {
  .arch .plaque { animation: stain .6s ease-out both; animation-delay: calc(var(--d, 0) * 1ms + 400ms); }
  .arch .tooth .plaque { animation-delay: calc(var(--i) * 70ms + 300ms); }
  @keyframes stain { from { opacity: 0; } }
}

/* 隐私 */
.privacy { background: #0f2a2e; color: #fff; border-radius: 32px; padding: 64px; display: grid; grid-template-columns: 1fr 1fr; gap: 48px; }
.privacy .eyebrow { color: var(--mint); }
.privacy h2 { font-size: clamp(28px, 4vw, 40px); margin: 8px 0 16px; }
.privacy p { color: rgba(255, 255, 255, .72); }
.privacy ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 18px; }
.privacy li { display: flex; gap: 14px; }
.privacy li::before { content: "✓"; flex: 0 0 28px; height: 28px; border-radius: 50%; background: rgba(127, 209, 185, .18); color: var(--mint); display: grid; place-items: center; font-weight: 700; }
.privacy li b { display: block; margin-bottom: 2px; }
.privacy li span { color: rgba(255, 255, 255, .72); font-size: 15px; }

/* 下载 */
.download { text-align: center; }
.download-cards { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; max-width: 760px; margin: 0 auto; text-align: left; }
/* 两张下载卡结构完全一致：标题 / 三行信息 / 按钮 / 备注 */
.dl { display: flex; flex-direction: column; }
.dl-head { display: flex; align-items: center; gap: 14px; }
.dl-head h3 { font-size: 22px; }
.dl-head p { font-size: 14px; color: var(--text-2); }
.platform { width: 44px; height: 44px; padding: 10px; border-radius: 12px; background: var(--accent-soft); fill: var(--accent); flex: none; }
.meta { display: grid; grid-template-columns: auto 1fr; margin: 24px 0; border-top: 1px solid var(--line); font-size: 14px; }
.meta dt, .meta dd { margin: 0; padding: 10px 0; border-bottom: 1px solid var(--line); }
.meta dt { color: var(--text-2); }
.meta dd { text-align: right; font-family: var(--font-mono); font-size: 13px; }
.dl .btn { justify-content: center; margin-top: auto; }
.dl-note { margin-top: 12px; min-height: 20px; font-size: 12px; color: var(--text-2); text-align: center; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.dl-note code { font-family: var(--font-mono); }

/* FAQ */
.faq { max-width: 760px; margin: 0 auto; display: grid; gap: 12px; }
.faq details { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 20px 24px; }
.faq summary { cursor: pointer; font-weight: 600; font-size: 17px; list-style: none; display: flex; justify-content: space-between; }
.faq summary::after { content: "+"; color: var(--accent); font-size: 22px; line-height: 1; }
.faq details[open] summary::after { content: "−"; }
.faq details p { color: var(--text-2); margin-top: 12px; }

/* 页脚 */
footer { border-top: 1px solid var(--line); padding: 48px 0; font-size: 14px; color: var(--text-2); }
footer .wrap { display: flex; justify-content: space-between; gap: 24px; flex-wrap: wrap; }
.footer-links { display: flex; gap: 24px; }
.footer-links a:hover { color: var(--text); }
.disclaimer { flex-basis: 100%; font-size: 13px; }
.version { font-family: var(--font-mono); font-size: 12px; }

@media (max-width: 880px) {
  section { padding: 64px 0; }
  .nav-links { display: none; }
  .hero .wrap, .regions, .privacy { grid-template-columns: 1fr; }
  .steps, .pga, .download-cards { grid-template-columns: 1fr; }
  .levels { grid-template-columns: 1fr 1fr; }
  .privacy { padding: 40px 28px; border-radius: 24px; }
}