/* 通风设计器 3D · 下载落地页（独立样式，不影响全站 style.css） */
:root {
  --bg: #07120f;
  --bg-soft: #0c1a17;
  --card: #11201c;
  --card-2: #152823;
  --line: #1f3a32;
  --text: #eaf6f1;
  --dim: #9bb8ad;
  --faint: #6a8a7e;
  --mint: #38d39f;
  --mint-2: #6ee7b7;
  --cyan: #4fd2e0;
  --blue: #4f8cff;
  --r: 18px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, "PingFang SC", "Helvetica Neue", "Microsoft YaHei", sans-serif;
  background:
    radial-gradient(1100px 520px at 85% -120px, rgba(56,211,159,.10), transparent 60%),
    radial-gradient(900px 480px at -10% -80px, rgba(79,210,224,.08), transparent 55%),
    var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
.wrap { width: 100%; max-width: 1040px; margin: 0 auto; padding: 0 20px; }

/* ---------- 顶栏 ---------- */
header {
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: blur(14px);
  background: rgba(7,18,15,.82);
  border-bottom: 1px solid rgba(255,255,255,.06);
}
nav { display: flex; align-items: center; gap: 10px; height: 58px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 1.02rem; }
.brand img { width: 30px; height: 30px; border-radius: 8px; display: block; }
.brand small { font-weight: 400; color: var(--faint); font-size: .72rem; letter-spacing: .06em; }
nav .spacer { flex: 1; }
nav .navlink { color: var(--dim); font-size: .9rem; padding: 6px 4px; transition: color .15s; }
nav .navlink:hover { color: var(--text); }
.nav-cta {
  background: var(--mint); color: #04130d; font-weight: 700; font-size: .88rem;
  padding: 8px 16px; border-radius: 10px; white-space: nowrap;
  box-shadow: 0 6px 20px rgba(56,211,159,.28);
}
.nav-cta:active { transform: scale(.97); }

/* ---------- 下载提示条 ---------- */
.inapp-tip {
  display: none; position: relative; z-index: 60;
  background: linear-gradient(90deg, #10241c, #163026);
  border-bottom: 1px solid rgba(56,211,159,.35);
  color: var(--mint-2); font-size: .86rem; text-align: center; padding: 10px 44px 10px 16px;
}
.inapp-tip b { color: #fff; }
.inapp-tip.show { display: block; }
.inapp-tip .x { position: absolute; right: 12px; top: 50%; transform: translateY(-50%); color: var(--dim); font-size: 1.1rem; padding: 4px 8px; cursor: pointer; }

/* ---------- Hero ---------- */
.hero { padding: 56px 0 30px; }
.hero-grid { display: grid; grid-template-columns: 1.15fr .85fr; gap: 44px; align-items: center; }
.app-icon {
  width: 92px; height: 92px; border-radius: 24px; display: block;
  box-shadow: 0 18px 44px rgba(0,0,0,.55), 0 0 0 1px rgba(255,255,255,.08) inset;
}
.hero h1 { font-size: 2.6rem; line-height: 1.2; margin: 18px 0 10px; letter-spacing: .01em; }
.hero h1 .hl { color: var(--mint); }
.hero .sub { color: var(--dim); font-size: 1.08rem; max-width: 460px; }
.hero .meta { margin-top: 14px; display: flex; gap: 8px; flex-wrap: wrap; }
.chip {
  font-size: .78rem; color: var(--dim); background: var(--card);
  border: 1px solid var(--line); border-radius: 999px; padding: 4px 12px;
}
.chip.mint { color: var(--mint); border-color: rgba(56,211,159,.35); }

.cta-row { margin-top: 28px; display: flex; flex-direction: column; gap: 10px; align-items: flex-start; }
.btn-download {
  display: inline-flex; align-items: center; gap: 12px;
  background: linear-gradient(135deg, var(--mint-2), var(--mint));
  color: #04130d; font-weight: 800; font-size: 1.12rem;
  padding: 17px 34px; border-radius: 16px;
  box-shadow: 0 14px 36px rgba(56,211,159,.30);
  transition: transform .12s, box-shadow .12s, filter .12s;
}
.btn-download:hover { filter: brightness(1.05); box-shadow: 0 18px 44px rgba(56,211,159,.4); }
.btn-download:active { transform: translateY(1px) scale(.99); }
.btn-download svg { width: 24px; height: 24px; }
.cta-note { color: var(--faint); font-size: .82rem; }
.cta-note a { color: var(--dim); text-decoration: underline; text-underline-offset: 3px; }
.cta-note a:hover { color: var(--mint); }

/* Hero 右侧：桌面应用窗口预览卡（无截图，用纯 CSS 还原应用主界面氛围） */
.hero-visual { position: relative; display: flex; justify-content: center; }
.win-card {
  width: 100%; max-width: 380px; border-radius: 18px; overflow: hidden;
  border: 1px solid rgba(255,255,255,.12);
  box-shadow: 0 40px 90px rgba(0,0,0,.6), 0 0 60px rgba(56,211,159,.08);
  background: #0a1a16;
}
.win-titlebar {
  height: 30px; background: #0e1f1a; border-bottom: 1px solid rgba(255,255,255,.06);
  display: flex; align-items: center; gap: 6px; padding: 0 12px;
}
.win-dot { width: 11px; height: 11px; border-radius: 50%; }
.win-dot.r { background: #ff5f57; }
.win-dot.y { background: #febc2e; }
.win-dot.g { background: #28c840; }
.win-titlebar .tb-title { margin-left: 10px; font-size: .72rem; color: var(--faint); }
.win-body {
  position: relative; padding: 22px; min-height: 220px;
  background:
    linear-gradient(180deg, #1a332a 0%, #0a1a16 100%);
}
.win-body .sky {
  position: absolute; left: 0; right: 0; top: 0; height: 70px;
  background: linear-gradient(180deg, rgba(135,206,250,.35), transparent);
}
.win-body .grid-floor {
  position: absolute; left: 22px; right: 22px; bottom: 22px; height: 90px;
  background-image:
    linear-gradient(rgba(56,211,159,.18) 1px, transparent 1px),
    linear-gradient(90deg, rgba(56,211,159,.18) 1px, transparent 1px);
  background-size: 28px 28px;
  mask-image: linear-gradient(180deg, transparent, #000 60%);
  -webkit-mask-image: linear-gradient(180deg, transparent, #000 60%);
}
.win-body .pipes {
  position: relative; display: flex; flex-direction: column; gap: 8px;
  align-items: center; padding-top: 14px;
}
.win-body .pipe {
  height: 14px; border-radius: 7px;
  background: linear-gradient(90deg, var(--mint), var(--cyan));
  box-shadow: 0 0 14px rgba(56,211,159,.45);
  opacity: .9;
}
.win-body .pipe:nth-child(1) { width: 78%; transform: rotate(-2deg); }
.win-body .pipe:nth-child(2) { width: 92%; }
.win-body .pipe:nth-child(3) { width: 64%; transform: rotate(1.5deg); }
.win-body .pipe:nth-child(4) { width: 86%; transform: rotate(-1deg); }
.win-body .badge-fan {
  position: absolute; right: 18px; top: 18px;
  font-size: .68rem; color: var(--mint); border: 1px solid rgba(56,211,159,.4);
  background: rgba(56,211,159,.08); border-radius: 999px; padding: 3px 10px;
  animation: spin 4s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
.win-toolbar {
  position: absolute; right: 14px; bottom: 14px; display: flex; flex-direction: column; gap: 6px;
}
.win-toolbar .tb-btn {
  width: 22px; height: 22px; border-radius: 6px;
  background: rgba(255,255,255,.06); border: 1px solid rgba(255,255,255,.1);
}
.qr-card {
  position: absolute; right: -6px; bottom: -18px;
  background: var(--card-2); border: 1px solid var(--line);
  border-radius: 16px; padding: 12px; text-align: center;
  box-shadow: 0 18px 44px rgba(0,0,0,.5);
}
.qr-card img { width: 96px; height: 96px; border-radius: 8px; display: block; }
.qr-card p { font-size: .72rem; color: var(--dim); margin-top: 7px; white-space: nowrap; }

/* ---------- 区块 ---------- */
section.block { padding: 58px 0 8px; }
.sec-head { text-align: center; margin-bottom: 34px; }
.sec-head h2 { font-size: 1.7rem; }
.sec-head p { color: var(--dim); margin-top: 8px; font-size: .98rem; }
.feat-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.feat {
  background: linear-gradient(180deg, var(--card), var(--bg-soft));
  border: 1px solid var(--line); border-radius: var(--r); padding: 24px 22px;
  transition: transform .15s, border-color .15s;
}
.feat:hover { transform: translateY(-3px); border-color: rgba(56,211,159,.4); }
.feat .ic {
  width: 42px; height: 42px; border-radius: 12px; display: grid; place-items: center;
  background: rgba(56,211,159,.12); margin-bottom: 14px;
}
.feat .ic svg { width: 22px; height: 22px; stroke: var(--mint); fill: none; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.feat h3 { font-size: 1.04rem; margin-bottom: 6px; }
.feat p { color: var(--dim); font-size: .88rem; }

/* ---------- 安装步骤 ---------- */
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.step {
  position: relative; background: var(--card); border: 1px solid var(--line);
  border-radius: var(--r); padding: 26px 22px 22px;
}
.step .num {
  width: 34px; height: 34px; border-radius: 50%; display: grid; place-items: center;
  background: linear-gradient(135deg, var(--mint-2), var(--mint)); color: #04130d;
  font-weight: 800; margin-bottom: 14px;
}
.step h3 { font-size: 1rem; margin-bottom: 6px; }
.step p { color: var(--dim); font-size: .86rem; }
.step .shot-mini { margin-top: 14px; border-radius: 12px; overflow: hidden; border: 1px solid var(--line); }
.step .shot-mini img { width: 100%; display: block; }

/* ---------- FAQ ---------- */
.faq { max-width: 760px; margin: 0 auto; display: flex; flex-direction: column; gap: 12px; }
.qa { background: var(--card); border: 1px solid var(--line); border-radius: 14px; overflow: hidden; }
.qa summary {
  cursor: pointer; list-style: none; padding: 17px 20px; font-weight: 600; font-size: .96rem;
  display: flex; align-items: center; gap: 10px;
}
.qa summary::-webkit-details-marker { display: none; }
.qa summary::after { content: "+"; margin-left: auto; color: var(--mint); font-size: 1.3rem; font-weight: 400; transition: transform .2s; }
.qa[open] summary::after { transform: rotate(45deg); }
.qa .a { padding: 0 20px 18px; color: var(--dim); font-size: .9rem; }
.qa .a b, .qa .a strong { color: var(--text); }
.qa .a .kbd {
  display: inline-block; background: var(--card-2); border: 1px solid var(--line);
  border-radius: 6px; padding: 1px 8px; font-size: .82rem; color: var(--mint-2);
}

/* ---------- 下载大卡（页面中段二次 CTA） ---------- */
.cta-band {
  margin: 64px 0 0; border-radius: 26px; padding: 44px 34px; text-align: center;
  background:
    radial-gradient(600px 240px at 50% -60px, rgba(56,211,159,.16), transparent 70%),
    var(--card);
  border: 1px solid rgba(56,211,159,.25);
}
.cta-band h2 { font-size: 1.6rem; }
.cta-band p { color: var(--dim); margin: 8px 0 24px; font-size: .95rem; }
.cta-band .btn-download { font-size: 1.05rem; padding: 15px 30px; }
.cta-band .alt { margin-top: 14px; font-size: .82rem; color: var(--faint); }
.cta-band .alt a { color: var(--dim); text-decoration: underline; text-underline-offset: 3px; }

/* Mac 用户提示 */
.mac-note {
  display: none; margin-top: 4px; padding: 12px 16px; border-radius: 12px;
  background: var(--bg-soft); border: 1px dashed var(--line);
  color: var(--dim); font-size: .84rem; text-align: left;
}
.cta-band .mac-note { margin: 14px auto 0; text-align: center; max-width: 460px; }
body.is-mac .mac-note { display: block; }

/* ---------- 微信二维码弹窗 ---------- */
.wx-link { color: var(--mint); text-decoration: underline; text-underline-offset: 3px; cursor: pointer; }
.wx-link:hover { color: var(--mint-2); }
.wx-mask {
  display: none; position: fixed; inset: 0; z-index: 100;
  background: rgba(5,10,8,.72); backdrop-filter: blur(6px);
  align-items: center; justify-content: center; padding: 24px;
}
.wx-mask.show { display: flex; }
.wx-box {
  position: relative; width: 100%; max-width: 330px; text-align: center;
  background: var(--card-2); border: 1px solid var(--line); border-radius: 22px;
  padding: 30px 26px 24px; box-shadow: 0 40px 100px rgba(0,0,0,.6);
  animation: wxPop .18s ease-out;
}
@keyframes wxPop { from { transform: scale(.94); opacity: 0; } to { transform: scale(1); opacity: 1; } }
.wx-box h3 { font-size: 1.15rem; }
.wx-sub { color: var(--dim); font-size: .85rem; margin-top: 6px; }
.wx-box img {
  display: block; width: 224px; max-width: 78%; height: auto; margin: 18px auto 0;
  background: #fff; padding: 10px; border-radius: 14px;
}
.wx-tip { color: var(--faint); font-size: .78rem; margin-top: 14px; line-height: 1.6; }
.wx-close {
  position: absolute; right: 10px; top: 8px; width: 36px; height: 36px;
  background: none; border: 0; color: var(--dim); font-size: 1.5rem; line-height: 1;
  cursor: pointer; border-radius: 50%;
}
.wx-close:hover { color: var(--text); background: rgba(255,255,255,.06); }

/* ---------- 页脚 ---------- */
footer { margin-top: 70px; border-top: 1px solid var(--line); padding: 30px 20px; text-align: center; color: var(--faint); font-size: .84rem; }
footer a { color: var(--dim); }

/* ---------- 响应式 ---------- */
@media (max-width: 860px) {
  .hero-grid { grid-template-columns: 1fr; gap: 36px; }
  .hero { padding: 36px 0 10px; text-align: center; }
  .hero .sub { margin: 0 auto; }
  .hero .meta { justify-content: center; }
  .cta-row { align-items: center; }
  .btn-download { width: 100%; justify-content: center; }
  .hero-visual { order: -1; }
  .qr-card { right: calc(50% - 175px); }
  .feat-grid, .steps { grid-template-columns: 1fr; }
  .hero h1 { font-size: 2rem; }
}
@media (max-width: 420px) {
  .win-card { max-width: 100%; }
  .brand small { display: none; }
}