/* ==========================================================================
   小比智能科技 · 设计系统基础层
   用法：改配色只改 :root 里的变量，全站生效
   ========================================================================== */

:root {
  /* ---- 底色：近黑，带一点冷调 ---- */
  --bg: #05060a;
  --bg-1: #080a10;
  --bg-2: #0b0e16;
  --bg-3: #10141f;

  /* ---- 描边 ---- */
  --line: rgba(255, 255, 255, 0.07);
  --line-2: rgba(255, 255, 255, 0.12);
  --line-3: rgba(255, 255, 255, 0.2);

  /* ---- 文字 ---- */
  --text: #eef1f7;
  --text-2: #99a2b4;
  --text-3: #5c6577;

  /* ---- 品牌色（冷蓝紫）---- */
  --brand: #4f7cff;
  --brand-2: #7c5cff;
  --accent: #00d6ff;
  --glow: rgba(79, 124, 255, 0.35);

  /* ---- 字体 ---- */
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC",
    sans-serif;
  --font-mono: "SF Mono", "JetBrains Mono", ui-monospace, Menlo, Consolas,
    "Courier New", monospace;

  /* ---- 版式节奏 ---- */
  --container: 1240px;
  --container-wide: 1440px;
  --gutter: 28px;
  --section-y: 118px;
  --radius: 4px;
  --radius-lg: 8px;

  /* ---- 动效曲线 ---- */
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
}

/* ==========================  重置  ========================== */

*,
*::before,
*::after {
  box-sizing: border-box;
}

* {
  margin: 0;
  padding: 0;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.65;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  text-rendering: optimizeLegibility;
}

img,
video,
svg,
canvas {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}

ul,
ol {
  list-style: none;
}

::selection {
  background: rgba(79, 124, 255, 0.32);
  color: #fff;
}

/* 滚动条（Webkit） */
::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}
::-webkit-scrollbar-track {
  background: var(--bg);
}
::-webkit-scrollbar-thumb {
  background: #1c2233;
  border-radius: 99px;
  border: 2px solid var(--bg);
}
::-webkit-scrollbar-thumb:hover {
  background: #2a3247;
}

/* ==========================  排版  ========================== */

h1,
h2,
h3,
h4,
h5 {
  font-weight: 500;
  line-height: 1.1;
  letter-spacing: -0.028em;
  color: var(--text);
}

/* 超大主标题 */
.t-display {
  font-size: clamp(2.05rem, 5.3vw, 4.6rem);
  line-height: 1.06;
  letter-spacing: -0.022em;
  font-weight: 500;
}

/* 章节标题 */
.t-h2 {
  font-size: clamp(1.9rem, 3.6vw, 3.1rem);
  line-height: 1.12;
  letter-spacing: -0.032em;
  font-weight: 500;
}

.t-h3 {
  font-size: clamp(1.3rem, 2vw, 1.7rem);
  line-height: 1.25;
  letter-spacing: -0.02em;
  font-weight: 500;
}

.t-h4 {
  font-size: 1.0625rem;
  line-height: 1.4;
  letter-spacing: -0.01em;
  font-weight: 500;
}

/* 正文 */
.t-body {
  font-size: 1.0625rem;
  line-height: 1.72;
  color: var(--text-2);
}

.t-body-lg {
  font-size: clamp(1.0625rem, 1.35vw, 1.25rem);
  line-height: 1.68;
  color: var(--text-2);
}

.t-small {
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--text-3);
}

/* 小标签：等宽大写，带一个方块前缀 */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-3);
}

.eyebrow::before {
  content: "";
  width: 5px;
  height: 5px;
  background: var(--brand);
  box-shadow: 0 0 10px var(--brand);
  flex: none;
}

.eyebrow--accent::before {
  background: var(--accent);
  box-shadow: 0 0 10px var(--accent);
}

/* 渐变文字 */
.grad-text {
  background: linear-gradient(96deg, #ffffff 8%, #b9c6ff 52%, #7c5cff 96%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

.dim {
  color: var(--text-3);
}

.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

/* ==========================  布局  ========================== */

.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.container--wide {
  max-width: var(--container-wide);
}

.section {
  position: relative;
  padding-block: var(--section-y);
}

.section--tight {
  padding-block: 92px;
}

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 40px;
  margin-bottom: 64px;
}

.section-head__left {
  max-width: 720px;
}

.section-head .eyebrow {
  margin-bottom: 22px;
}

.section-head .t-h2 {
  margin-bottom: 20px;
}

.section-head .t-body {
  max-width: 560px;
}

/* 顶部分隔线 */
.hr {
  height: 1px;
  background: var(--line);
  border: 0;
}

/* ==========================  按钮  ========================== */

.btn {
  --btn-bg: transparent;
  --btn-fg: var(--text);
  --btn-bd: var(--line-2);
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  height: 46px;
  padding-inline: 24px;
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  color: var(--btn-fg);
  background: var(--btn-bg);
  border: 1px solid var(--btn-bd);
  border-radius: 99px;
  transition: background 0.35s var(--ease), border-color 0.35s var(--ease),
    color 0.35s var(--ease), transform 0.35s var(--ease),
    box-shadow 0.35s var(--ease);
  white-space: nowrap;
}

.btn svg {
  width: 15px;
  height: 15px;
  transition: transform 0.35s var(--ease);
}

.btn:hover {
  transform: translateY(-1px);
}

.btn:hover svg {
  transform: translateX(3px);
}

/* 主按钮：实心亮色 */
.btn--primary {
  --btn-bg: #ffffff;
  --btn-fg: #05060a;
  --btn-bd: #ffffff;
}

.btn--primary:hover {
  box-shadow: 0 8px 30px -8px rgba(255, 255, 255, 0.45);
}

/* 品牌按钮：品牌色渐变 */
.btn--brand {
  --btn-bg: linear-gradient(100deg, var(--brand) 0%, var(--brand-2) 100%);
  --btn-fg: #ffffff;
  --btn-bd: transparent;
}

.btn--brand:hover {
  box-shadow: 0 10px 34px -10px var(--glow);
}

/* 幽灵按钮 */
.btn--ghost:hover {
  --btn-bd: var(--line-3);
  --btn-bg: rgba(255, 255, 255, 0.04);
}

/* 文字链接 */
.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text);
  padding-bottom: 4px;
  border-bottom: 1px solid var(--line-2);
  transition: border-color 0.3s var(--ease), gap 0.3s var(--ease);
}

.link-arrow svg {
  width: 14px;
  height: 14px;
  transition: transform 0.3s var(--ease);
}

.link-arrow:hover {
  border-color: var(--brand);
}

.link-arrow:hover svg {
  transform: translateX(3px);
}

/* ==========================  卡片 / 网格  ========================== */

.panel {
  position: relative;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.035), rgba(255, 255, 255, 0.012));
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: border-color 0.4s var(--ease), background 0.4s var(--ease);
}

.panel:hover {
  border-color: var(--line-2);
}

/* 鼠标跟随光晕（由 JS 写入 --mx / --my） */
.panel--spot::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.4s var(--ease);
  background: radial-gradient(
    340px circle at var(--mx, 50%) var(--my, 50%),
    rgba(79, 124, 255, 0.14),
    transparent 65%
  );
}

.panel--spot:hover::after {
  opacity: 1;
}

/* 细网格底纹 */
.grid-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 88px 88px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 0%, transparent 78%);
  -webkit-mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 0%, transparent 78%);
  opacity: 0.6;
}

/* ==========================  滚动揭示  ========================== */
/* 注意：只有 html 带 .js 时才隐藏，保证禁用 JS / 爬虫抓取时内容可见 */

.js [data-reveal] {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity 0.9s var(--ease-out), transform 0.9s var(--ease-out);
  transition-delay: var(--delay, 0ms);
  will-change: opacity, transform;
}

.js [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

/* 逐条错开 */
.stagger > * {
  --delay: calc(var(--i, 0) * 70ms);
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .js [data-reveal] {
    opacity: 1;
    transform: none;
  }
  html {
    scroll-behavior: auto;
  }
}

/* ==========================  辅助类  ========================== */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.no-wrap {
  white-space: nowrap;
}

.stack-lg > * + * {
  margin-top: 28px;
}

@media (max-width: 900px) {
  :root {
    --section-y: 88px;
    --gutter: 20px;
  }
  .section-head {
    margin-bottom: 44px;
  }
}