*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --page:       #FBF4E4;   /* 书页主底色 */
  --page-deep:  #F5EAD2;   /* 深一层底色 */
  --card:       #FFFCF2;   /* 卡片 */
  --ink:        #3A3128;   /* 主文字 */
  --ink-2:      #6B5D4A;   /* 次要文字 */
  --ink-3:      #9C8D74;   /* 弱化文字 */
  --line:       #E8D9B8;   /* 分割线 */
  --line-soft:  #F1E6CD;   /* 极浅分割线 */
  --accent:     #B5743A;   /* 暖棕橙 */
  --accent-deep:#8E5728;
  --accent-soft:#F2E1C6;
  --max: 980px;
}

html { scroll-behavior: smooth; }

body {
  font-family: "Noto Serif SC", "Songti SC", "SimSun", serif;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink);
  background-color: var(--page);
  background-image:
    radial-gradient(ellipse at 12% 0%, rgba(212, 176, 110, 0.16), transparent 55%),
    radial-gradient(ellipse at 88% 100%, rgba(181, 116, 58, 0.08), transparent 55%);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* 纸张颗粒感 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: 0.5;
  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='3' stitchTiles='stitch'/%3E%3CfeColorMatrix type='saturate' values='0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.035'/%3E%3C/svg%3E");
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

section[id] { scroll-margin-top: 84px; }

/* ============ 顶部 ============ */
.site-head {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(251, 244, 228, 0.9);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line-soft);
}

.head-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  position: relative;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
}

.logo-mark {
  width: 34px;
  height: 34px;
  flex-shrink: 0;
  border-radius: 8px;
  background: var(--accent);
  color: #FFF8E8;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0;
}

.logo-text {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: #2E261D;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.main-nav {
  display: flex;
  gap: 2px;
}

.main-nav a {
  font-size: 14.5px;
  color: var(--ink-2);
  padding: 7px 14px;
  border-radius: 6px;
  letter-spacing: 0.06em;
  transition: background .2s, color .2s;
}

.main-nav a:hover {
  background: var(--accent-soft);
  color: var(--accent-deep);
}

.menu-btn {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  color: var(--ink);
  align-items: center;
  justify-content: center;
}

/* ============ 首页介绍 ============ */
.intro { padding: 96px 0 76px; }

.intro-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
}

.intro-hi {
  font-size: 15px;
  color: var(--accent);
  letter-spacing: 0.14em;
  margin-bottom: 20px;
}

.intro h1 {
  font-size: clamp(27px, 4.6vw, 42px);
  font-weight: 700;
  line-height: 1.52;
  letter-spacing: 0.03em;
  color: #2E261D;
  max-width: 720px;
  margin-bottom: 26px;
}

.intro-p {
  font-size: 16px;
  color: var(--ink-2);
  line-height: 2.05;
  max-width: 620px;
}

/* ============ 笔记列表 ============ */
.notes { padding: 20px 0 88px; }

.notes-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
}

.notes-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--line);
}

.notes-head h2 {
  font-size: 19px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: #2E261D;
}

.filters {
  display: flex;
  gap: 2px;
  flex-wrap: wrap;
}

.filters button {
  font-family: inherit;
  font-size: 13.5px;
  background: none;
  border: none;
  color: var(--ink-3);
  padding: 5px 13px;
  border-radius: 20px;
  cursor: pointer;
  letter-spacing: 0.06em;
  transition: background .2s, color .2s;
}

.filters button:hover { color: var(--accent-deep); background: var(--accent-soft); }

.filters button.on {
  color: #FFF8E8;
  background: var(--accent);
}

.note {
  display: grid;
  grid-template-columns: 106px 1fr;
  gap: 26px;
  padding: 28px 0;
  border-bottom: 1px solid var(--line-soft);
}

.note-meta {
  font-size: 13px;
  color: var(--ink-3);
  line-height: 1.7;
  padding-top: 3px;
  letter-spacing: 0.04em;
}

.note-meta .tag {
  display: inline-block;
  font-size: 11.5px;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 1px 9px;
  border-radius: 20px;
  margin-bottom: 7px;
  letter-spacing: 0.08em;
}

.note-title {
  font-size: 18px;
  font-weight: 700;
  line-height: 1.62;
  color: #2E261D;
  letter-spacing: 0.02em;
  margin-bottom: 9px;
  transition: color .2s;
}

.note:hover .note-title { color: var(--accent-deep); }

.note-excerpt {
  font-size: 14.5px;
  color: var(--ink-2);
  line-height: 1.92;
}

/* ============ 关于 ============ */
.about {
  background: var(--page-deep);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 76px 0;
}

.about-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
}

.about-inner h2 {
  font-size: 19px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: #2E261D;
  margin-bottom: 30px;
}

.about-inner p {
  font-size: 15.5px;
  color: var(--ink-2);
  line-height: 2.1;
  max-width: 640px;
  margin-bottom: 18px;
}

.about-inner p:last-child { margin-bottom: 0; }

/* ============ 页脚 ============ */
.site-foot {
  padding: 48px 0 44px;
  text-align: center;
  font-size: 13px;
  color: var(--ink-3);
  line-height: 2.1;
  letter-spacing: 0.05em;
}

.foot-beian {
  display: inline-block;
  color: var(--ink-3);
  border-bottom: 1px dashed var(--line);
  padding-bottom: 1px;
  transition: color .2s, border-color .2s;
}

.foot-beian:hover {
  color: var(--accent-deep);
  border-color: var(--accent);
}

/* ============ 响应式 ============ */
@media (max-width: 720px) {
  .head-inner { padding: 0 18px; }

  .menu-btn { display: flex; }

  .main-nav {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--page);
    border-bottom: 1px solid var(--line);
    flex-direction: column;
    gap: 2px;
    padding: 8px 12px 14px;
  }

  .main-nav.open { display: flex; }
  .main-nav a { padding: 11px 14px; }

  .intro { padding: 58px 0 46px; }
  .intro-inner, .notes-inner, .about-inner { padding: 0 18px; }

  .notes { padding: 12px 0 60px; }

  .notes-head {
    align-items: flex-start;
    gap: 12px;
  }

  .note {
    grid-template-columns: 1fr;
    gap: 10px;
    padding: 24px 0;
  }

  .note-meta {
    display: flex;
    align-items: center;
    gap: 10px;
    padding-top: 0;
  }

  .note-meta .tag { margin-bottom: 0; }

  .about { padding: 56px 0; }
}