:root {
  --color-bg: #ffffff;
  --color-bg-alt: #f7f8fa;
  --color-text: #1f2933;
  --color-text-muted: #64748b;
  --color-accent: #2563eb;
  --color-accent-dark: #1d4ed8;
  --color-border: #e5e7eb;
  --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.06);
  --shadow-md: 0 6px 24px rgba(15, 23, 42, 0.08);
  --radius: 12px;
  --container-max: 1040px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

/* 顶部导航 */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

.site-header.scrolled {
  border-bottom-color: var(--color-border);
  box-shadow: var(--shadow-sm);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-brand {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.brand-dot {
  color: var(--color-accent);
}

.nav-links {
  display: flex;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  transition: color 0.2s ease;
}

.nav-links a:hover {
  color: var(--color-accent);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
}

.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--color-text);
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.nav-toggle.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle.open span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* 首页 */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: 64px;
}

.hero-inner {
  padding: 48px 24px;
}

.hero-greet {
  color: var(--color-accent);
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.hero-name {
  font-size: clamp(2.6rem, 7vw, 4.5rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.1;
}

.hero-title {
  font-size: clamp(1.1rem, 2.5vw, 1.4rem);
  color: var(--color-text-muted);
  margin-top: 12px;
}

.hero-desc {
  max-width: 560px;
  color: var(--color-text-muted);
  margin-top: 20px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 36px;
}

/* 按钮 */
.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: 999px;
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: background 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
}

.btn-primary {
  background: var(--color-accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-accent-dark);
  box-shadow: 0 6px 18px rgba(37, 99, 235, 0.3);
}

.btn-outline {
  border: 1px solid var(--color-border);
  color: var(--color-text);
}

.btn-outline:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* 通用区块 */
.section {
  padding: 96px 0;
}

.section-alt {
  background: var(--color-bg-alt);
}

.section-title {
  font-size: clamp(1.6rem, 4vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 48px;
  position: relative;
}

.section-title::after {
  content: "";
  display: block;
  width: 44px;
  height: 3px;
  border-radius: 2px;
  background: var(--color-accent);
  margin-top: 12px;
}

/* 关于我 */
.about-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 48px;
  align-items: start;
}

.about-text p {
  color: var(--color-text-muted);
  margin-bottom: 16px;
}

.about-info {
  list-style: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 24px;
  background: var(--color-bg);
}

.about-info li {
  display: flex;
  justify-content: space-between;
  padding: 10px 0;
  border-bottom: 1px solid var(--color-border);
  font-size: 0.95rem;
}

.about-info li:last-child {
  border-bottom: none;
}

.info-label {
  color: var(--color-text-muted);
}

/* 技能 */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.skill-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.skill-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.skill-card h3 {
  font-size: 1.05rem;
  margin-bottom: 12px;
  color: var(--color-accent);
}

.skill-card p {
  color: var(--color-text-muted);
  font-size: 0.92rem;
  line-height: 1.9;
}

/* 项目作品 */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.project-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.project-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.project-thumb {
  height: 160px;
  background-size: cover;
  background-position: center;
}

.thumb-1 {
  background-image: linear-gradient(135deg, #60a5fa, #2563eb);
}

.thumb-2 {
  background-image: linear-gradient(135deg, #34d399, #059669);
}

.thumb-3 {
  background-image: linear-gradient(135deg, #fbbf24, #f59e0b);
}

.project-body {
  padding: 20px;
}

.project-body h3 {
  font-size: 1.05rem;
  margin-bottom: 8px;
}

.project-body p {
  color: var(--color-text-muted);
  font-size: 0.92rem;
  margin-bottom: 14px;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.project-tags span {
  font-size: 0.78rem;
  color: var(--color-accent);
  background: rgba(37, 99, 235, 0.08);
  padding: 4px 10px;
  border-radius: 999px;
}

/* 联系我 */
.contact-lead {
  color: var(--color-text-muted);
  text-align: center;
  margin-bottom: 36px;
}

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

.contact-item {
  display: inline-block;
  padding: 12px 28px;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  color: var(--color-text);
  text-decoration: none;
  font-size: 0.95rem;
  background: var(--color-bg);
  transition: border-color 0.2s ease, color 0.2s ease, transform 0.2s ease;
}

.contact-item:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  transform: translateY(-2px);
}

/* 页脚 */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 28px 24px;
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

/* 响应式 */
@media (max-width: 860px) {
  .about-grid {
    grid-template-columns: 1fr;
  }

  .projects-grid {
    grid-template-columns: 1fr;
  }

  .skills-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .nav-links {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }

  .nav-links.open {
    max-height: 320px;
  }

  .nav-links li {
    border-top: 1px solid var(--color-border);
  }

  .nav-links a {
    display: block;
    padding: 16px 24px;
  }

  .nav-toggle {
    display: flex;
  }
}