/* =========================================================
   Hydranautics 静态展示站 - 统一样式
   纯静态 / 无后台 / 无框架
   ========================================================= */

:root {
  --blue: #0066b3;
  --blue-dark: #004c87;
  --teal: #00a0b0;
  --teal-light: #4cc9d6;
  --ink: #1a2733;
  --muted: #5a6b7b;
  --line: #e3e9ef;
  --bg: #ffffff;
  --bg-soft: #f4f8fb;
  --bg-deep: #0b2238;
  --radius: 12px;
  --shadow: 0 8px 28px rgba(11, 34, 56, 0.10);
  --shadow-sm: 0 2px 10px rgba(11, 34, 56, 0.08);
  --maxw: 1180px;
  --font: "Segoe UI", "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--blue); text-decoration: none; }
a:hover { color: var(--teal); }

img { max-width: 100%; display: block; }

.container {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 22px;
}

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  color: var(--ink);
  font-size: 18px;
}
.brand:hover { color: var(--ink); }
.brand .logo { height: 36px; width: auto; }
.brand small { display: block; font-weight: 500; font-size: 11px; color: var(--muted); letter-spacing: .5px; }

.nav-links {
  display: flex;
  gap: 28px;
  list-style: none;
  margin: 0;
  padding: 0;
  align-items: center;
}
.nav-links a {
  color: var(--ink);
  font-size: 15px;
  font-weight: 500;
  position: relative;
  padding: 6px 0;
}
.nav-links a::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 0; height: 2px;
  background: var(--teal);
  transition: width .25s ease;
}
.nav-links a:hover::after,
.nav-links a.active::after { width: 100%; }
.nav-links a:hover { color: var(--blue); }

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}
.nav-toggle span {
  display: block;
  width: 24px; height: 2px;
  background: var(--ink);
  margin: 5px 0;
  transition: .3s;
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  color: #fff;
  background:
    radial-gradient(1200px 500px at 80% -10%, rgba(0,160,176,.45), transparent 60%),
    linear-gradient(135deg, var(--blue-dark) 0%, var(--blue) 55%, var(--teal) 120%);
  overflow: hidden;
}
.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle at 20% 30%, rgba(255,255,255,.10) 0 2px, transparent 3px),
    radial-gradient(circle at 70% 60%, rgba(255,255,255,.08) 0 2px, transparent 3px),
    radial-gradient(circle at 45% 80%, rgba(255,255,255,.06) 0 2px, transparent 3px);
  background-size: 220px 220px, 320px 320px, 280px 280px;
  opacity: .5;
}
.hero-inner {
  position: relative;
  z-index: 1;
  padding: 92px 0 100px;
  max-width: 760px;
}
.hero .eyebrow {
  display: inline-block;
  font-size: 13px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--teal-light);
  border: 1px solid rgba(255,255,255,.3);
  padding: 5px 14px;
  border-radius: 30px;
  margin-bottom: 20px;
}
.hero h1 {
  font-size: clamp(30px, 5vw, 50px);
  line-height: 1.2;
  margin: 0 0 18px;
  font-weight: 800;
}
.hero p {
  font-size: clamp(15px, 2vw, 19px);
  color: rgba(255,255,255,.9);
  margin: 0 0 30px;
  max-width: 620px;
}
.hero .slogan {
  font-style: italic;
  color: var(--teal-light);
  margin-bottom: 28px;
  font-size: 17px;
}
.btn {
  display: inline-block;
  padding: 13px 28px;
  border-radius: 30px;
  font-weight: 600;
  font-size: 15px;
  transition: transform .15s ease, box-shadow .2s ease;
}
.btn-primary { background: #fff; color: var(--blue); }
.btn-primary:hover { color: var(--blue); transform: translateY(-2px); box-shadow: 0 10px 24px rgba(0,0,0,.18); }
.btn-ghost { background: transparent; color: #fff; border: 1px solid rgba(255,255,255,.6); }
.btn-ghost:hover { color: #fff; background: rgba(255,255,255,.1); }
.btn-blue { background: var(--blue); color: #fff; }
.btn-blue:hover { color: #fff; transform: translateY(-2px); box-shadow: var(--shadow); }

/* ---------- Section ---------- */
.section { padding: 72px 0; }
.section.soft { background: var(--bg-soft); }
.section-head { text-align: center; max-width: 720px; margin: 0 auto 44px; }
.section-head .kicker {
  color: var(--teal);
  font-weight: 700;
  letter-spacing: 2px;
  font-size: 13px;
  text-transform: uppercase;
}
.section-head h2 {
  font-size: clamp(24px, 3.4vw, 34px);
  margin: 10px 0 12px;
  color: var(--ink);
}
.section-head p { color: var(--muted); margin: 0; }

/* ---------- About ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 48px;
  align-items: center;
}
.about-text p { color: var(--muted); margin: 0 0 16px; }
.about-text strong { color: var(--ink); }
.stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}
.stat {
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  text-align: center;
}
.stat b { display: block; font-size: 28px; color: var(--blue); }
.stat span { font-size: 13px; color: var(--muted); }

/* ---------- Product cards ---------- */
.product-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}
.product-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  transition: transform .2s ease, box-shadow .2s ease;
}
.product-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.product-card .tag {
  align-self: flex-start;
  background: var(--bg-soft);
  color: var(--teal);
  font-size: 12px;
  font-weight: 700;
  padding: 4px 12px;
  border-radius: 20px;
  margin-bottom: 14px;
}
.product-card h3 { margin: 0 0 10px; font-size: 19px; }
.product-card p { color: var(--muted); margin: 0 0 18px; font-size: 14.5px; flex: 1; }
.product-card .more { font-weight: 600; font-size: 14px; }

/* ---------- Product detail ---------- */
.detail-hero {
  background: linear-gradient(135deg, var(--blue-dark), var(--teal));
  color: #fff;
  padding: 56px 0;
}
.detail-hero .tag {
  display: inline-block;
  background: rgba(255,255,255,.15);
  padding: 4px 14px; border-radius: 20px;
  font-size: 12px; letter-spacing: 1px; margin-bottom: 14px;
}
.detail-hero h1 { margin: 0 0 10px; font-size: clamp(26px, 4vw, 38px); }
.detail-hero p { margin: 0; color: rgba(255,255,255,.9); max-width: 720px; }
.detail-body { padding: 60px 0; }
.detail-body h2 { font-size: 24px; margin: 0 0 16px; color: var(--blue-dark); }
.detail-body h3 { font-size: 18px; margin: 28px 0 10px; color: var(--ink); }
.detail-body p, .detail-body li { color: var(--muted); }
.detail-body ul { padding-left: 20px; }
.detail-body ul li { margin-bottom: 8px; }
.spec-table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  font-size: 14.5px;
}
.spec-table th, .spec-table td {
  border: 1px solid var(--line);
  padding: 12px 14px;
  text-align: left;
}
.spec-table th { background: var(--bg-soft); color: var(--ink); width: 38%; }
.callout {
  background: var(--bg-soft);
  border-left: 4px solid var(--teal);
  padding: 16px 20px;
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--muted);
  margin: 24px 0;
}

/* ---------- Downloads ---------- */
.download-list { display: grid; gap: 16px; }
.download-item {
  display: flex;
  align-items: center;
  gap: 18px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 22px;
  box-shadow: var(--shadow-sm);
  transition: transform .15s ease, box-shadow .2s ease;
}
.download-item:hover { transform: translateY(-2px); box-shadow: var(--shadow); }
.download-item .ico {
  width: 46px; height: 46px;
  border-radius: 10px;
  background: var(--blue);
  color: #fff;
  display: grid; place-items: center;
  font-weight: 700; font-size: 13px;
  flex-shrink: 0;
}
.download-item .meta { flex: 1; }
.download-item .meta b { display: block; color: var(--ink); font-size: 16px; }
.download-item .meta span { font-size: 13px; color: var(--muted); }

/* ---------- Contact ---------- */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; }
.contact-info p { color: var(--muted); }
.contact-info .row { margin-bottom: 14px; }
.contact-info .row b { color: var(--ink); display: block; font-size: 14px; }
.contact-form { display: grid; gap: 14px; }
.contact-form input, .contact-form textarea {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  font-family: var(--font);
  font-size: 14.5px;
  background: #fff;
  color: var(--ink);
}
.contact-form input:focus, .contact-form textarea:focus {
  outline: none; border-color: var(--teal);
  box-shadow: 0 0 0 3px rgba(0,160,176,.15);
}
.contact-form textarea { min-height: 120px; resize: vertical; }
.note { font-size: 13px; color: var(--muted); }

/* ---------- Breadcrumb ---------- */
.crumb { font-size: 13px; color: var(--muted); padding: 16px 0 0; }
.crumb a { color: var(--muted); }
.crumb a:hover { color: var(--blue); }

/* ---------- Footer ---------- */
.site-footer {
  background: var(--bg-deep);
  color: rgba(255,255,255,.75);
  padding: 48px 0 28px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: 32px;
  margin-bottom: 32px;
}
.site-footer h4 { color: #fff; font-size: 15px; margin: 0 0 14px; }
.site-footer ul { list-style: none; padding: 0; margin: 0; }
.site-footer ul li { margin-bottom: 9px; }
.site-footer ul a { color: rgba(255,255,255,.7); font-size: 14px; }
.site-footer ul a:hover { color: #fff; }
.footer-brand p { font-size: 13.5px; color: rgba(255,255,255,.6); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.12);
  padding-top: 18px;
  font-size: 13px;
  color: rgba(255,255,255,.5);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
}

/* ---------- Responsive ---------- */
@media (max-width: 880px) {
  .nav-links {
    position: absolute;
    top: 68px; left: 0; right: 0;
    background: #fff;
    flex-direction: column;
    gap: 0;
    padding: 8px 22px 18px;
    border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow);
    display: none;
  }
  .nav-links.open { display: flex; }
  .nav-links li { width: 100%; }
  .nav-links a { display: block; padding: 12px 0; border-bottom: 1px solid var(--line); }
  .nav-links a::after { display: none; }
  .nav-toggle { display: block; }

  .about-grid, .product-grid, .contact-grid, .footer-grid {
    grid-template-columns: 1fr;
  }
  .footer-grid { gap: 24px; }
  .section { padding: 56px 0; }
}

/* ---------- Modal (下载闸门) ---------- */
.modal {
  position: fixed; inset: 0; z-index: 100;
  display: none; align-items: center; justify-content: center;
  padding: 20px;
}
.modal.open { display: flex; }
.modal-backdrop {
  position: absolute; inset: 0;
  background: rgba(11, 34, 56, .55);
}
.modal-box {
  position: relative;
  background: #fff;
  border-radius: 14px;
  max-width: 420px; width: 100%;
  padding: 28px 26px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, .3);
  animation: pop .2s ease;
}
@keyframes pop {
  from { transform: translateY(10px) scale(.98); opacity: 0; }
  to { transform: none; opacity: 1; }
}
.modal-box h3 { margin: 0 0 6px; color: var(--ink); font-size: 20px; }
.modal-close {
  position: absolute; top: 12px; right: 14px;
  border: none; background: none; font-size: 24px; line-height: 1;
  color: var(--muted); cursor: pointer;
}
.dl-form { display: grid; gap: 12px; margin-top: 14px; }
.dl-form label { font-size: 13.5px; color: var(--ink); font-weight: 600; display: grid; gap: 5px; }
.dl-form input {
  width: 100%; padding: 10px 12px;
  border: 1px solid var(--line); border-radius: 9px;
  font-family: var(--font); font-size: 14.5px; color: var(--ink);
}
.dl-form input:focus {
  outline: none; border-color: var(--teal);
  box-shadow: 0 0 0 3px rgba(0, 160, 176, .15);
}
.dl-err { color: #d93025; font-size: 13px; margin: 0; min-height: 16px; }