/* ===== 主题变量 ===== */
:root {
  --bg: #ffffff;
  --fg: #3f3f3f;
  --heading: #4a4a4a;
  --muted: #6b6b6b;
  --link: #529ce0;
  --border: #e8e8e8;
  --nav-bg: #ffffff;
  --sidebar-w: 340px;
}

html[data-theme="dark"] {
  --bg: #1b1b1b;
  --fg: #d8d8d8;
  --heading: #eaeaea;
  --muted: #9a9a9a;
  --link: #7cb9ee;
  --border: #333333;
  --nav-bg: #1b1b1b;
}

/* ===== 基础 ===== */
* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
               "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 17px;
  line-height: 1.7;
  transition: background 0.25s, color 0.25s;
}

a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }

h1, h2, h3 { color: var(--heading); font-weight: 700; line-height: 1.3; }
h1 { font-size: 2.6rem; margin: 0 0 1.6rem; }
h2 { font-size: 1.35rem; margin: 2rem 0 0.6rem; }

/* ===== 顶部导航 ===== */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--nav-bg);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 2.2rem;
  padding: 0.9rem 3rem;
  flex-wrap: wrap;
}

.brand {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--heading);
  margin-right: 2rem;
}
.brand:hover { text-decoration: none; }

.nav-link {
  font-size: 1.1rem;
  color: var(--heading);
  font-weight: 400;
}

.nav-link.active { font-weight: 700; }

.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--heading);
  padding: 0;
  display: flex;
  align-items: center;
}
.theme-toggle svg { width: 20px; height: 20px; }

/* ===== 主体布局 ===== */
.layout {
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  gap: 3.5rem;
  max-width: 1240px;
  margin: 0 auto;
  padding: 3rem 3rem 5rem;
}

/* ===== 左侧栏 ===== */
.avatar {
  width: 100%;
  max-width: 280px;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border-radius: 50%;          /* 椭圆头像 */
  display: block;
  margin-bottom: 1.6rem;
}

.profile-name {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--heading);
  margin: 0 0 0.3rem;
}

.profile-role {
  color: var(--muted);
  margin: 0 0 1.6rem;
}

.contact-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.contact-list li {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  margin-bottom: 0.75rem;
  color: var(--fg);
}

.contact-list svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  fill: currentColor;
}

.icon-linkedin { fill: #0a66c2 !important; }

/* ===== 右侧内容 ===== */
.content ul { padding-left: 1.4rem; }
.content li { margin-bottom: 0.5rem; }
.content ul ul { margin-top: 0.5rem; }

/* ===== 响应式 ===== */
@media (max-width: 860px) {
  .layout {
    grid-template-columns: 1fr;
    gap: 2.5rem;
    padding: 2rem 1.5rem 4rem;
  }
  .navbar { padding: 0.8rem 1.5rem; gap: 1.2rem; }
  .brand { margin-right: 0; width: 100%; }
  .avatar { margin: 0 auto 1.5rem; }
  h1 { font-size: 2rem; }
}