/* ==========================================================================
   克莱因蓝个人网 · 基础层（base）
   设计系统 / 全局重置 / 导航 / 页面容器 / 手账胶带
   —— 样式与原始单文件页面逐行一致，仅拆分为独立文件便于维护。
   ========================================================================== */

/* ============================================================
   设计系统：Riso 印刷 & 拼贴风 (深化版)
   ============================================================ */
:root {
  --bg-color: #F6F5F2;
  --riso-blue: #3D68A8;
  --riso-blue-dark: #1E3A66;
  --riso-blue-light: #8DB2E4;
  --text-color: #1A1A1A;
  --stamp-red: #D0533A;         /* 朱砂红印章色 */

  --font-typewriter: 'Courier Prime', 'Noto Sans SC', 'Courier New', monospace;
  --font-pixel: 'Space Mono', 'Noto Sans SC', monospace;
  --font-accent: 'Space Grotesk', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;

  --shadow-hard: 4px 4px 0 var(--riso-blue);
  --shadow-hard-dark: 4px 4px 0 var(--text-color);

  /* 版面尺度令牌：统一内容宽度 / 页边距 / 板块间距 */
  --content-max: 1180px;
  --gutter: clamp(20px, 5vw, 56px);
  --section-gap: clamp(56px, 8vw, 104px);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: var(--font-accent);
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.8; /* 增加行距，提升呼吸感 */
  letter-spacing: 0.5px; /* 增加字距 */
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* 纸张颗粒：SVG 噪点经 contrast 锐化后以 multiply 叠印在整页上 */
body::before {
  content: '';
  position: fixed; inset: 0; z-index: 9999;
  pointer-events: none;
  mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3CfeColorMatrix type='saturate' values='0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  opacity: 0.14;
  filter: contrast(180%);
}
a { text-decoration: none; color: inherit; transition: all 0.2s; }
button { cursor: pointer; font-family: inherit; border: none; background: none; }
img { max-width: 100%; display: block; }

/* 双语排版：中文为主，英文降为印刷装饰层 */
.en { font-family: var(--font-typewriter); font-size: 10px; letter-spacing: 1px; opacity: 0.72; text-transform: uppercase; }
.cn { display: block; font-family: var(--font-typewriter); font-size: 11px; letter-spacing: 0; opacity: 0.92; }

/* ============================================================
   全局导航栏
   ============================================================ */
header {
  position: fixed; top: 0; left: 0; right: 0;
  max-width: var(--content-max); margin: 0 auto;
  padding: 18px var(--gutter);
  display: flex; justify-content: space-between; align-items: flex-start;
  gap: 16px;
  z-index: 1000; pointer-events: none;
}
.nav-tag {
  background: var(--riso-blue); color: #fff; padding: 8px 16px; font-size: 14px; font-weight: 700;
  text-transform: uppercase; letter-spacing: 2px; transform: rotate(-2deg);
  box-shadow: 2px 2px 0 var(--riso-blue-dark); pointer-events: auto;
}
.nav-links {
  display: flex; flex-wrap: wrap; gap: 8px; justify-content: flex-end; pointer-events: auto;
}
.nav-links button {
  background: #fff; border: 1px solid var(--text-color);
  padding: 6px 12px; font-size: 13px; font-weight: 700; letter-spacing: 1px;
  box-shadow: 2px 2px 0 var(--text-color); transition: all 0.15s ease;
}
.nav-links button:hover { transform: translate(2px, 2px); box-shadow: 0 0 0 transparent; background: var(--riso-blue-light); color: #fff; }
.nav-links button.active { background: var(--riso-blue); color: #fff; border-color: var(--riso-blue-dark); box-shadow: 2px 2px 0 var(--riso-blue-dark); }

/* ============================================================
   页面容器与动画
   ============================================================ */
main { padding: 96px var(--gutter) var(--section-gap); max-width: var(--content-max); margin: 0 auto; min-height: 100vh; }
.page-view { display: none; animation: fadeIn 0.4s ease; }
.page-view.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(15px); } to { opacity: 1; transform: translateY(0); } }

.page-title { font-family: var(--font-pixel); font-size: 34px; font-weight: 900; margin-bottom: 40px; display: flex; align-items: center; gap: 16px; letter-spacing: 2px; }
.page-title span { font-family: var(--font-typewriter); font-size: 14px; background: var(--riso-blue); color: #fff; padding: 4px 12px; transform: rotate(-2deg); letter-spacing: 1px; }

/* 真实手账胶带 (带锯齿和叠加效果) */
.tape {
  position: absolute; width: 100px; height: 28px;
  background: rgba(255, 255, 255, 0.75);
  border-left: 1px dashed rgba(0,0,0,0.1); border-right: 1px dashed rgba(0,0,0,0.1);
  backdrop-filter: blur(1px); z-index: 10;
  mix-blend-mode: overlay;
  clip-path: polygon(2% 0, 98% 2%, 100% 100%, 0 98%); /* 锯齿边缘 */
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}
.tape-top { top: -14px; left: 50%; transform: translateX(-50%) rotate(2deg); }