/* ==========================================================================
   EzBubble 产品官网 · 极简 HIG 风格
   设计约定：
   - 全站唯一强调色 = 气泡蓝（--accent），只用在 CTA 与「气泡」符号上
   - 系统字体栈，Mac 用苹方、Windows 用微软雅黑
   - 占位统一 .ph 虚线框，替换真实素材时整块换成 <img> 即可
   ========================================================================== */

:root {
  --bg:        #ffffff;   /* 图纸白 */
  --bg-alt:    #f5f5f7;   /* 版面灰 */
  --text:      #1d1d1f;   /* 墨线黑 */
  --text-2:    #6e6e73;   /* 注释灰 */
  --text-3:    #a1a1a6;   /* 弱化灰 */
  --border:    #d2d2d7;   /* 边框银 */
  --accent:    #0a84ff;   /* 气泡蓝 */
  --accent-h:  #0071e3;   /* 气泡蓝 · 悬停 */
  --radius:    18px;
  --container: 1080px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 76px;   /* 锚点跳转不被吸顶导航遮住 */
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro SC", "PingFang SC",
               "Segoe UI", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 { letter-spacing: -0.02em; line-height: 1.25; }
::selection { background: rgba(10, 132, 255, 0.15); }

.container { width: min(var(--container), 92%); margin-inline: auto; }
.container-narrow { width: min(760px, 92%); }

a { color: inherit; text-decoration: none; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }

/* ---------- 按钮：全站只推一个主 CTA ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  border-radius: 999px;
  font-weight: 600;
  transition: background-color .15s ease, color .15s ease, opacity .15s ease;
}

.btn-primary { background: var(--accent); color: #fff; padding: 12px 26px; font-size: 15px; }
.btn-primary:hover { background: var(--accent-h); }

.btn-ghost { color: var(--accent); padding: 12px 10px; font-size: 15px; }
.btn-ghost:hover { opacity: .75; }

.btn-sm { padding: 8px 18px; font-size: 14px; }
.btn-lg { padding: 15px 34px; font-size: 17px; margin-top: 34px; }

/* ---------- 导航 ---------- */

.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, .82);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid rgba(0, 0, 0, .06);
}

.nav-inner { display: flex; align-items: center; gap: 28px; height: 60px; }

.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-size: 17px;
  font-weight: 700;
  margin-right: auto;
}

/* 品牌标记 = 一个气泡圈 */
.brand-balloon {
  width: 13px;
  height: 13px;
  border: 2.5px solid var(--accent);
  border-radius: 50%;
  flex: none;
}

.nav-links { display: flex; gap: 26px; }
.nav-links a { font-size: 14.5px; color: var(--text-2); }
.nav-links a:hover { color: var(--text); }

/* ---------- 首屏：一个承诺 + 一张示意图 ---------- */

.hero { padding: 96px 0 88px; text-align: center; }

.eyebrow {
  font-size: 13.5px;
  font-weight: 600;
  letter-spacing: .06em;
  color: var(--accent);
  margin-bottom: 14px;
}

.hero h1 { font-size: clamp(34px, 5.6vw, 58px); font-weight: 700; }

.hero-sub {
  max-width: 620px;
  margin: 22px auto 0;
  font-size: 18.5px;
  line-height: 1.75;
  color: var(--text-2);
}

.hero-cta {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
  margin-top: 34px;
}

.hero-note { margin-top: 16px; font-size: 13.5px; color: var(--text-3); }

.hero-visual { max-width: 880px; margin: 72px auto 0; }

.hero-svg {
  width: 100%;
  height: auto;
  display: block;
  background: #fbfbfd;
  border: 1px solid var(--border);
  border-radius: 20px;
  box-shadow: 0 24px 64px rgba(0, 0, 0, .07);
}

.hero-visual figcaption { margin-top: 14px; font-size: 13px; color: var(--text-3); }

/* ---------- 通用分节 ---------- */

.section { padding: 96px 0; }
.section-alt { background: var(--bg-alt); }

.section h2 { font-size: clamp(26px, 3.6vw, 38px); font-weight: 700; }

.section-lead {
  max-width: 560px;
  margin-top: 14px;
  font-size: 16.5px;
  line-height: 1.75;
  color: var(--text-2);
}

.section-lead-center { margin-inline: auto; }

/* ---------- 占位框：所有待补充素材的统一样式 ---------- */

.ph {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 7px;
  aspect-ratio: 16 / 10;
  border: 1.5px dashed #c7c7cc;
  border-radius: var(--radius);
  background: #fafafa;
  padding: 20px;
  text-align: center;
}

.ph-label { font-size: 14px; font-weight: 600; color: var(--text-3); }
.ph-hint  { font-size: 12.5px; color: var(--text-3); line-height: 1.65; max-width: 90%; }

.ph-wide { aspect-ratio: 21 / 9; margin-top: 64px; }
.ph-card { aspect-ratio: 4 / 3; border-radius: 12px; margin-bottom: 18px; }

.todo {
  border-bottom: 1px dashed var(--text-3);
  color: var(--text-3);
}

/* ---------- 功能：截图位紧挨主张 ---------- */

.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 56px 40px;
  margin-top: 56px;
}

.feature h3 { font-size: 20px; margin: 22px 0 10px; }
.feature p { font-size: 15.5px; line-height: 1.75; color: var(--text-2); }

/* ---------- 工作方式：三步 ---------- */

.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 44px;
  margin-top: 56px;
}

/* 步骤序号复用「气泡」母题 */
.step-num {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: 2px solid var(--accent);
  border-radius: 50%;
  color: var(--accent);
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 18px;
}

.step h3 { font-size: 18px; margin-bottom: 8px; }
.step p { font-size: 15px; line-height: 1.75; color: var(--text-2); }

/* ---------- 证据：案例卡片 ---------- */

.proof-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 56px;
}

.proof-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
}

.proof-meta { font-size: 13.5px; line-height: 2; color: var(--text-2); }
.proof-meta b { color: var(--text); font-weight: 600; }

.proof-note {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
  margin-top: 44px;
  padding: 26px 30px;
  background: var(--bg-alt);
  border-radius: var(--radius);
}

.proof-note p { font-size: 15px; color: var(--text-2); max-width: 640px; }

/* ---------- 下载 / 联系我们 ---------- */

.cta-section { text-align: center; }

.cta-meta { margin-top: 18px; font-size: 14px; color: var(--text-2); }

.chips {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 34px;
  scroll-margin-top: 90px;
}

.chip {
  border: 1.5px dashed #c7c7cc;
  border-radius: 999px;
  padding: 8px 20px;
  font-size: 13.5px;
  color: var(--text-3);
  background: var(--bg);
}

/* ---------- 常见问题 ---------- */

.faq { margin-top: 34px; }

.faq details { border-bottom: 1px solid var(--border); }

.faq summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 20px 2px;
  font-size: 16.5px;
  font-weight: 600;
}

.faq summary::-webkit-details-marker { display: none; }

.faq summary::after {
  content: "+";
  color: var(--accent);
  font-size: 22px;
  font-weight: 400;
  line-height: 1;
  transition: transform .18s ease;
  flex: none;
}

.faq details[open] summary::after { transform: rotate(45deg); }

.faq details p {
  padding: 0 2px 20px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-2);
}

/* ---------- 页脚 ---------- */

.footer {
  border-top: 1px solid var(--border);
  padding: 30px 0;
  font-size: 13.5px;
  color: var(--text-3);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 14px;
}

.footer-links { display: flex; gap: 22px; }
.footer-links a:hover { color: var(--text); }

/* ---------- 响应式 ---------- */

@media (max-width: 860px) {
  .hero { padding: 64px 0 64px; }
  .section { padding: 72px 0; }

  .nav-links { display: none; }

  .feature-grid { grid-template-columns: 1fr; gap: 48px; }
  .steps { grid-template-columns: 1fr; gap: 36px; }
  .proof-grid { grid-template-columns: 1fr; }

  .proof-note { flex-direction: column; align-items: flex-start; }

  .hero-visual { margin-top: 48px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; }
}