/* 落地页和内容页的配色变量、基础、导航、hero。从 A0_styles_landing.css 拆出来, 页面按顺序加载。 */

/**
 站点页（landing / 能做什么 / 怎么用）的样式，跟应用页 A2_styles.css 分开。

 landing 整页深色（body.dark-page），因为它主要是一块蓝底加四张图；
 内容页是亮色。两种页面共用同一套 nav、卡片、按钮，靠 body 上的 class 切换配色。
 */

:root {
  color-scheme: light;
  --surface: #ffffff;
  --page: #f5f5f2;
  --band: #fbfbf9;
  --text-primary: #0b0b0b;
  --text-secondary: #52514e;
  --text-muted: #898781;
  --border: rgba(11, 11, 11, 0.09);
  --border-strong: rgba(11, 11, 11, 0.16);
  --accent: #2a78d6;
  --accent-2: #4a3aa7;
  --accent-soft: rgba(42, 120, 214, 0.10);
  --warm: #eda100;
  --wash: rgba(11, 11, 11, 0.04);
  --shadow-sm: 0 1px 2px rgba(11, 11, 11, 0.04);
  --shadow: 0 1px 2px rgba(11, 11, 11, 0.04), 0 8px 26px rgba(11, 11, 11, 0.07);
  --shadow-lg: 0 2px 8px rgba(11, 11, 11, 0.06), 0 22px 54px rgba(11, 11, 11, 0.11);
  --sans: system-ui, -apple-system, "Segoe UI", "Microsoft YaHei", sans-serif;
  --nav-h: 62px;

  /* 深色块用的固定值, 不跟随明暗模式 —— 它是这一页的视觉主体 */
  --ink: #ffffff;
  --dim: rgba(255, 255, 255, 0.72);
  --faint: rgba(255, 255, 255, 0.13);
  --glass: rgba(255, 255, 255, 0.06);
  --deep: #16183a;
}

@media (prefers-color-scheme: dark) {
  :root:where(:not([data-theme="light"])) {
    color-scheme: dark;
    --surface: #212120;
    --page: #0d0d0d;
    --band: #161615;
    --text-primary: #ffffff;
    --text-secondary: #c3c2b7;
    --text-muted: #898781;
    --border: rgba(255, 255, 255, 0.09);
    --border-strong: rgba(255, 255, 255, 0.18);
    --accent: #3987e5;
    --accent-2: #9085e9;
    --accent-soft: rgba(57, 135, 229, 0.14);
    --warm: #c98500;
    --wash: rgba(255, 255, 255, 0.05);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.5);
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.5), 0 8px 26px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 2px 8px rgba(0, 0, 0, 0.5), 0 22px 54px rgba(0, 0, 0, 0.55);
  }
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --surface: #212120;
  --page: #0d0d0d;
  --band: #161615;
  --text-primary: #ffffff;
  --text-secondary: #c3c2b7;
  --text-muted: #898781;
  --border: rgba(255, 255, 255, 0.09);
  --border-strong: rgba(255, 255, 255, 0.18);
  --accent: #3987e5;
  --accent-2: #9085e9;
  --accent-soft: rgba(57, 135, 229, 0.14);
  --warm: #c98500;
  --wash: rgba(255, 255, 255, 0.05);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.5);
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.5), 0 8px 26px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 2px 8px rgba(0, 0, 0, 0.5), 0 22px 54px rgba(0, 0, 0, 0.55);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-primary);
  background: var(--page);
  -webkit-font-smoothing: antialiased;
  scroll-behavior: smooth;
}

/* landing 整页深色, 从上到下一块蓝 */
body.dark-page {
  color: var(--ink);
  background:
    radial-gradient(1100px 520px at 12% 2%, rgba(74, 58, 167, 0.55), transparent 62%),
    radial-gradient(900px 460px at 88% 14%, rgba(27, 175, 122, 0.24), transparent 60%),
    radial-gradient(800px 500px at 50% 96%, rgba(237, 161, 0, 0.16), transparent 64%),
    linear-gradient(162deg, #141636 0%, #1b1d47 45%, #221a4a 100%);
  background-color: var(--deep);
  background-attachment: fixed;
}

/* ---------------- 导航 ---------------- */

/**
 所有页面共用同一条导航栏, 配色跟应用页的顶栏一致(A2_styles.css 里的 #topbar)。
 landing、能做什么、怎么用、应用之间来回点, 顶上这条不变。
 */
nav {
  position: sticky;
  top: 0;
  z-index: 40;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 34px;
  color: var(--ink);
  background: linear-gradient(100deg, #0f1128 0%, #15142f 60%, #1a1338 100%);
  border-bottom: 1px solid rgba(0, 0, 0, 0.35);
}

.logo { display: flex; align-items: center; gap: 11px; text-decoration: none; color: inherit; }

.brand-mark { display: flex; align-items: flex-end; gap: 3px; height: 24px; }
.brand-mark .bar { width: 5px; border-radius: 2px 2px 1px 1px; }
.brand-mark .b1 { height: 11px; background: #57a5ff; }
.brand-mark .b2 { height: 21px; background: #9085e9; }
.brand-mark .b3 { height: 15px; background: #f5c451; }

.logo-text { font-size: 16px; font-weight: 660; letter-spacing: -0.015em; color: var(--ink); }
.logo-sub { font-size: 12px; font-weight: 400; color: var(--dim); margin-left: 8px; }

.nav-links { display: flex; align-items: center; gap: 3px; }
.nav-links a {
  font-size: 13.5px;
  color: var(--dim);
  text-decoration: none;
  padding: 7px 13px;
  border-radius: 8px;
  transition: color 0.16s, background 0.16s;
}
.nav-links a:hover, .nav-links a.on { color: var(--ink); background: var(--glass); }

.nav-lang {
  font: inherit;
  font-size: 12px;
  font-weight: 600;
  color: var(--dim);
  background: none;
  border: 1px solid var(--faint);
  border-radius: 8px;
  padding: 5px 11px;
  margin-left: 6px;
  cursor: pointer;
  transition: color 0.16s, border-color 0.16s;
}
.nav-lang:hover { color: var(--ink); border-color: rgba(255, 255, 255, 0.4); }

.nav-cta {
  margin-left: 10px;
  color: var(--deep) !important;
  background: #ffffff !important;
  font-weight: 550;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.25);
  transition: opacity 0.16s, transform 0.16s;
}
.nav-cta:hover { opacity: 0.92; transform: translateY(-1px); }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: 0;
  padding: 8px;
  cursor: pointer;
}
.nav-toggle span { width: 19px; height: 2px; background: var(--ink); border-radius: 1px; }

/* ---------------- landing 的 hero ---------------- */

.hero { position: relative; padding: 66px 24px 78px; }

/* 细网格, 让大块深色不至于太平 */
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.04) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(1000px 460px at 50% 12%, #000 18%, transparent 76%);
  pointer-events: none;
}

.hero-inner { position: relative; max-width: 720px; margin: 0 auto; text-align: center; }

.hero-badge {
  display: inline-block;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.03em;
  color: var(--dim);
  background: var(--glass);
  border: 1px solid var(--faint);
  border-radius: 999px;
  padding: 5px 16px;
  margin-bottom: 24px;
}

.hero h1 {
  font-size: clamp(36px, 6.4vw, 58px);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1.14;
  margin: 0 0 20px;
  color: var(--ink);
}

.hero-sub {
  max-width: 600px;
  margin: 0 auto 32px;
  color: var(--dim);
  font-size: 16.5px;
  line-height: 1.85;
}

.hero-btns { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

.btn-primary, .btn-secondary {
  display: inline-block;
  font-size: 14.5px;
  font-weight: 550;
  padding: 12px 28px;
  border-radius: 11px;
  text-decoration: none;
  transition: transform 0.15s, box-shadow 0.15s, background 0.15s, opacity 0.15s;
}
.btn-primary {
  color: var(--deep);
  background: #ffffff;
  box-shadow: 0 6px 22px rgba(0, 0, 0, 0.28);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 10px 30px rgba(0, 0, 0, 0.34); }
.btn-secondary {
  color: var(--ink);
  background: var(--glass);
  border: 1px solid var(--faint);
}
.btn-secondary:hover { background: rgba(255, 255, 255, 0.13); }

/* 亮色页里的按钮换配色 */
body:not(.dark-page) .btn-primary {
  color: #fff;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  box-shadow: var(--shadow);
}
body:not(.dark-page) .btn-secondary {
  color: var(--text-secondary);
  background: var(--surface);
  border: 1px solid var(--border-strong);
}
body:not(.dark-page) .btn-secondary:hover { color: var(--accent); border-color: var(--accent); }