/* ============================================================
   筑境 ZHUJING — 原型设计系统
   base.css : 变量 / 重置 / 排版 / 栅格 / 通用工具类
   视觉语言参考 dora.plus：纯白底、黑字、发丝边框、大圆角、极少阴影
   ============================================================ */

:root {
  /* 墨色层级 */
  --ink: #111111;
  --ink-2: #2b2b2b;
  --ink-3: #5f5f5f;
  --ink-4: #8a8a8a;
  --ink-5: #b4b4b4;
  --ink-6: #d6d6d6;

  /* 面与线 */
  --bg: #ffffff;
  --bg-2: #f7f7f8;
  --bg-3: #f1f1f2;
  --bg-4: #ebebec;
  --line: #e8e8e8;
  --line-2: #f0f0f0;
  --line-dark: rgba(255, 255, 255, 0.14);

  /* 暖色（影像底） */
  --warm: #f6f1e8;
  --warm-2: #efe7db;
  --warm-3: #e3d8c8;

  /* 功能色（克制使用） */
  --ok: #2f7d55;
  --ok-bg: #eef6f1;
  --warn: #a8712a;
  --warn-bg: #fbf3e6;
  --danger: #b04a3f;
  --danger-bg: #fbeeed;
  --info: #3c5f8a;
  --info-bg: #eef2f8;

  /* 圆角 */
  --r-xs: 8px;
  --r-s: 10px;
  --r-m: 14px;
  --r-l: 20px;
  --r-xl: 26px;
  --r-2xl: 34px;
  --r-full: 999px;

  /* 阴影 */
  --sh-1: 0 1px 2px rgba(17, 17, 17, 0.05);
  --sh-2: 0 6px 22px rgba(17, 17, 17, 0.06);
  --sh-3: 0 16px 44px rgba(17, 17, 17, 0.1);
  --sh-4: 0 28px 70px rgba(17, 17, 17, 0.16);

  /* 动效 */
  --ease: cubic-bezier(0.22, 0.8, 0.24, 1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --t-fast: 0.18s;
  --t: 0.32s;
  --t-slow: 0.6s;

  /* 尺寸 */
  --nav-h: 60px;
  --page-max: 1440px;
  --gutter: 48px;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
    "PingFang SC", "HarmonyOS Sans SC", "Hiragino Sans GB", "Microsoft YaHei",
    "Helvetica Neue", Arial, sans-serif;
  font-size: 15px;
  line-height: 1.6;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: "tnum" on, "lnum" on;
}

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

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

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

input,
textarea,
select {
  font: inherit;
  color: inherit;
}

ul,
ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

h1,
h2,
h3,
h4,
h5 {
  margin: 0;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.15;
}

p {
  margin: 0;
}

::selection {
  background: rgba(17, 17, 17, 0.12);
}

/* ---------- 滚动条 ---------- */
::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}
::-webkit-scrollbar-thumb {
  background: #dcdcdc;
  border-radius: 99px;
  border: 3px solid #fff;
}
::-webkit-scrollbar-thumb:hover {
  background: #c6c6c6;
}
::-webkit-scrollbar-track {
  background: transparent;
}

.thin-scroll::-webkit-scrollbar {
  width: 6px;
}
.thin-scroll::-webkit-scrollbar-thumb {
  border: 0;
  background: #e0e0e0;
}

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

.display {
  font-size: clamp(40px, 5.4vw, 72px);
  line-height: 1.06;
  letter-spacing: -0.035em;
  font-weight: 600;
}

.h1 {
  font-size: clamp(30px, 3.2vw, 42px);
  letter-spacing: -0.03em;
}

.h2 {
  font-size: clamp(24px, 2.4vw, 32px);
  letter-spacing: -0.025em;
}

.h3 {
  font-size: 20px;
  letter-spacing: -0.02em;
}

.h4 {
  font-size: 16px;
  letter-spacing: -0.01em;
}

.lead {
  font-size: 16px;
  line-height: 1.7;
  color: var(--ink-3);
  font-weight: 400;
}

.muted {
  color: var(--ink-4);
}

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

.eyebrow {
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-4);
  font-weight: 500;
}

.mono {
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum";
}

.num {
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
}

.t-sm {
  font-size: 13px;
}
.t-xs {
  font-size: 12px;
}
.t-xxs {
  font-size: 11px;
}
.t-lg {
  font-size: 17px;
}

.w-500 {
  font-weight: 500;
}
.w-600 {
  font-weight: 600;
}

.center {
  text-align: center;
}
.right {
  text-align: right;
}

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

.wrap {
  width: 100%;
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.wrap-narrow {
  max-width: 980px;
}

.section {
  padding-top: 110px;
  padding-bottom: 110px;
}

.section-sm {
  padding-top: 72px;
  padding-bottom: 72px;
}

.sec-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 40px;
  margin-bottom: 44px;
}

.sec-head .eyebrow {
  margin-bottom: 14px;
  display: block;
}

.row {
  display: flex;
  align-items: center;
  gap: 12px;
}
.row-between {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.col {
  display: flex;
  flex-direction: column;
}
.gap-4 {
  gap: 4px;
}
.gap-6 {
  gap: 6px;
}
.gap-8 {
  gap: 8px;
}
.gap-10 {
  gap: 10px;
}
.gap-12 {
  gap: 12px;
}
.gap-16 {
  gap: 16px;
}
.gap-20 {
  gap: 20px;
}
.gap-24 {
  gap: 24px;
}
.gap-32 {
  gap: 32px;
}
.flex-1 {
  flex: 1;
  min-width: 0;
}
.wrap-w {
  flex-wrap: wrap;
}

.grid {
  display: grid;
  gap: 20px;
}
.g-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.g-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
.g-4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}
.g-5 {
  grid-template-columns: repeat(5, minmax(0, 1fr));
}

.divider {
  height: 1px;
  background: var(--line);
  border: 0;
  margin: 0;
}

.hide {
  display: none !important;
}

/* ---------- 入场动画 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.9s var(--ease-out), transform 0.9s var(--ease-out);
}
.reveal.in {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  html {
    scroll-behavior: auto;
  }
}

/* ============================================================
   响应式基线
   ============================================================ */

@media (max-width: 1200px) {
  :root {
    --gutter: 32px;
  }
  .g-5 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .g-4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 900px) {
  :root {
    --gutter: 20px;
    --nav-h: 56px;
  }
  .section {
    padding-top: 64px;
    padding-bottom: 64px;
  }
  .g-3 {
    grid-template-columns: 1fr;
  }
  .g-5 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .sec-head {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }
}