/* ===== 基础变量与重置 ===== */
:root {
  --primary: #5B8DEF;        /* 柔和主蓝 */
  --primary-dark: #4A90D9;   /* 深一点的蓝，用于 hover */
  --bg: #f7f9fc;             /* 极浅灰背景 */
  --card: #ffffff;           /* 白色卡片 */
  --text: #333333;           /* 深灰文字 */
  --muted: #6b7280;          /* 次要文字 */
  --shadow: 0 8px 24px rgba(91, 141, 239, 0.12);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* ===== 顶部导航栏 ===== */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(91, 141, 239, 0.12);
}

.nav-container {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 20px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  letter-spacing: 0.5px;
}

.nav-menu {
  list-style: none;
  display: flex;
  gap: 8px;
}

.nav-link {
  display: inline-block;
  padding: 8px 16px;
  border-radius: 999px;
  color: var(--text);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s, background 0.2s;
}

.nav-link:hover,
.nav-link.active {
  color: #fff;
  background: var(--primary);
}

/* 移动端汉堡按钮 */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 42px;
  height: 42px;
  background: transparent;
  border: none;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  height: 2px;
  width: 22px;
  background: var(--primary);
  border-radius: 2px;
  transition: transform 0.25s, opacity 0.25s;
}

.nav-toggle.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.active span:nth-child(2) { opacity: 0; }
.nav-toggle.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===== 主体容器 ===== */
main {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 20px;
}

section {
  padding: 72px 0;
}

.section-title {
  text-align: center;
  font-size: 1.8rem;
  margin-bottom: 28px;
  color: var(--text);
}

.section-title::after {
  content: "";
  display: block;
  width: 48px;
  height: 3px;
  margin: 12px auto 0;
  border-radius: 3px;
  background: var(--primary);
}

/* ===== 首页 Hero ===== */
.hero {
  text-align: center;
  padding-top: 80px;
  padding-bottom: 80px;
}

.avatar {
  width: 150px;
  height: 150px;
  margin: 0 auto 24px;
  border-radius: 50%;
  overflow: hidden;
  box-shadow: var(--shadow);
  border: 4px solid #fff;
}

.avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.name {
  font-size: 2.6rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 10px;
}

.tagline {
  font-size: 1.1rem;
  color: var(--muted);
  margin-bottom: 28px;
}

.btn {
  display: inline-block;
  padding: 12px 32px;
  background: var(--primary);
  color: #fff;
  border-radius: 999px;
  text-decoration: none;
  font-weight: 600;
  box-shadow: var(--shadow);
  transition: background 0.2s, transform 0.2s;
}

.btn:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
}

/* ===== 关于我 ===== */
.about-text {
  max-width: 680px;
  margin: 0 auto;
  text-align: center;
  font-size: 1.05rem;
  color: var(--text);
  background: var(--card);
  padding: 32px;
  border-radius: 18px;
  box-shadow: var(--shadow);
}

/* ===== 联系我 ===== */
.contact {
  text-align: center;
}

.contact-text {
  color: var(--muted);
  margin-bottom: 24px;
}

.socials {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.social {
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: var(--card);
  color: var(--primary);
  font-size: 1.3rem;
  text-decoration: none;
  box-shadow: var(--shadow);
  transition: background 0.2s, color 0.2s, transform 0.2s;
}

.social:hover {
  background: var(--primary);
  color: #fff;
  transform: translateY(-3px);
}

/* ===== 页脚 ===== */
.footer {
  text-align: center;
  padding: 28px 20px;
  color: var(--muted);
  font-size: 0.9rem;
  border-top: 1px solid rgba(91, 141, 239, 0.12);
  margin-top: 20px;
}

/* ===== 响应式设计 ===== */
@media (max-width: 640px) {
  .nav-toggle { display: flex; }

  .nav-menu {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: #fff;
    border-bottom: 1px solid rgba(91, 141, 239, 0.12);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }

  .nav-menu.open {
    max-height: 240px;
  }

  .nav-link {
    display: block;
    text-align: center;
    padding: 14px;
    border-radius: 0;
  }

  .name { font-size: 2.1rem; }
  section { padding: 56px 0; }
  .about-text { padding: 24px; }
}