/* ========== 主题变量 ========== */
:root {
  --color-bg-deep:       #0a0e27;
  --color-bg-section:    #0f1538;
  --color-bg-card:       #151b42;
  --color-bg-card-hover: #1a2255;
  --color-accent-cyan:   #00d4ff;
  --color-accent-blue:   #0066ff;
  --color-text-primary:  #e8ecf4;
  --color-text-secondary:#8a93b0;
  --color-text-muted:    #5a6380;
  --gradient-accent:      linear-gradient(135deg, #0066ff, #00d4ff);
  --gradient-accent-text: linear-gradient(90deg, #0066ff, #00d4ff);
  --space-xs:  0.5rem;
  --space-sm:  1rem;
  --space-md:  1.5rem;
  --space-lg:  2.5rem;
  --space-xl:  4rem;
  --space-2xl: 6rem;
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --font-size-hero: clamp(1.75rem, 5vw, 3.25rem);
  --font-size-h2:    clamp(1.5rem, 3vw, 2.25rem);
  --font-size-body:  1rem;
  --font-size-small: 0.875rem;
  --max-width: 1200px;
  --nav-height: 64px;
  --transition-fast: 0.2s ease;
  --transition-base: 0.3s ease;
  --transition-slow: 0.6s ease;
}

/* ========== 基础重置 ========== */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-body);
  line-height: 1.7;
  color: var(--color-text-secondary);
  background: var(--color-bg-deep);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: var(--color-accent-cyan);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: #fff;
}

img, svg {
  display: block;
}

ul {
  list-style: none;
}

/* ========== 无障碍 ========== */
.skip-link {
  position: absolute;
  top: -100%;
  left: 0;
  background: var(--color-accent-blue);
  color: #fff;
  padding: 0.5rem 1rem;
  z-index: 9999;
  font-size: var(--font-size-small);
}

.skip-link:focus {
  top: 0;
}

:focus-visible {
  outline: 2px solid var(--color-accent-cyan);
  outline-offset: 2px;
}

/* ========== 容器 ========== */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-sm);
}

/* ========== 导航栏 ========== */
#navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  transition: background var(--transition-base), box-shadow var(--transition-base);
}

#navbar.scrolled {
  background: rgba(10, 14, 39, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 rgba(0, 212, 255, 0.06);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-sm);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--color-text-primary);
  font-weight: 600;
  font-size: 1.1rem;
}

.nav-logo:hover {
  color: var(--color-text-primary);
}

.nav-logo svg {
  width: 28px;
  height: 28px;
}

.nav-links {
  display: flex;
  gap: var(--space-lg);
}

.nav-links a {
  color: var(--color-text-secondary);
  font-size: var(--font-size-small);
  font-weight: 500;
  transition: color var(--transition-fast);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-accent);
  border-radius: 1px;
  transition: width var(--transition-base);
}

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

.nav-links a:hover::after {
  width: 100%;
}

/* 汉堡菜单按钮 */
.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 32px;
  height: 32px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.menu-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--color-text-primary);
  border-radius: 1px;
  transition: transform var(--transition-base), opacity var(--transition-base);
  transform-origin: center;
}

.menu-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.menu-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ========== Hero ========== */
#hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

#particles {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  padding: var(--space-xl) var(--space-sm);
  max-width: 1000px;
}

.hero-content h1 {
  font-size: var(--font-size-hero);
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: var(--space-md);
}

.gradient-text {
  background: var(--gradient-accent-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(0.9rem, 2vw, 1.15rem);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-lg);
  letter-spacing: 0.05em;
}

.cta-button {
  display: inline-block;
  padding: 0.8rem 2.2rem;
  background: var(--gradient-accent);
  color: #fff;
  border: none;
  border-radius: 50px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  text-decoration: none;
}

.cta-button:hover {
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(0, 102, 255, 0.35);
}

.cta-large {
  padding: 1rem 2.5rem;
  font-size: 1.05rem;
}

/* ========== 通用板块 ========== */
section {
  padding: clamp(4rem, 8vh, 7rem) 0;
}

#skills,
#advantages {
  background: var(--color-bg-section);
}

#projects,
#contact {
  background: var(--color-bg-deep);
}

.section-title {
  font-size: var(--font-size-h2);
  font-weight: 700;
  color: var(--color-text-primary);
  text-align: center;
  margin-bottom: 0.5rem;
  position: relative;
}

.section-title::after {
  content: '';
  display: block;
  width: 48px;
  height: 3px;
  background: var(--gradient-accent);
  border-radius: 2px;
  margin: 0.75rem auto 0;
}

.section-desc {
  text-align: center;
  color: var(--color-text-muted);
  font-size: var(--font-size-small);
  margin-bottom: var(--space-xl);
}

/* ========== 卡片 ========== */
.card-grid {
  display: grid;
  gap: var(--space-md);
}

.skills-grid {
  grid-template-columns: repeat(3, 1fr);
}

.projects-grid {
  grid-template-columns: repeat(3, 1fr);
}

.advantages-grid {
  grid-template-columns: repeat(4, 1fr);
}

.card {
  background: var(--color-bg-card);
  border: 1px solid rgba(0, 212, 255, 0.06);
  border-radius: 12px;
  padding: var(--space-md);
  transition: transform var(--transition-base),
              border-color var(--transition-base),
              box-shadow var(--transition-base);
}

.card:hover {
  transform: translateY(-4px);
  border-color: rgba(0, 212, 255, 0.2);
  box-shadow: 0 8px 32px rgba(0, 102, 255, 0.1);
}

.card-icon {
  width: 48px;
  height: 48px;
  margin-bottom: var(--space-sm);
  color: var(--color-accent-cyan);
}

.card-icon svg {
  width: 100%;
  height: 100%;
}

.card h3 {
  color: var(--color-text-primary);
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.card p {
  font-size: var(--font-size-small);
  line-height: 1.6;
  color: var(--color-text-secondary);
}

/* 项目卡片标签 */
.card-tag {
  display: inline-block;
  padding: 0.15rem 0.6rem;
  font-size: 0.75rem;
  color: var(--color-accent-cyan);
  background: rgba(0, 212, 255, 0.08);
  border: 1px solid rgba(0, 212, 255, 0.15);
  border-radius: 20px;
  margin-bottom: 0.75rem;
}

/* ========== 联系方式 ========== */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-md);
  max-width: 900px;
  margin: 0 auto var(--space-lg);
}

.contact-card {
  background: var(--color-bg-card);
  border: 1px solid rgba(0, 212, 255, 0.06);
  border-radius: 12px;
  padding: var(--space-lg) var(--space-md);
  text-align: center;
  transition: transform var(--transition-base),
              border-color var(--transition-base),
              box-shadow var(--transition-base);
}

.contact-card:hover {
  transform: translateY(-4px);
  border-color: rgba(0, 212, 255, 0.2);
  box-shadow: 0 8px 32px rgba(0, 102, 255, 0.1);
}

.contact-icon {
  width: 40px;
  height: 40px;
  margin: 0 auto var(--space-sm);
  color: var(--color-accent-cyan);
}

.contact-icon svg {
  width: 100%;
  height: 100%;
}

.contact-card h3 {
  color: var(--color-text-primary);
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
}

.contact-value {
  font-size: var(--font-size-small);
  color: var(--color-text-secondary);
}

a.contact-value:hover {
  color: var(--color-accent-cyan);
}

.wechat-card {
  position: relative;
  border-color: rgba(0, 212, 255, 0.12);
}

.wechat-card::before {
  content: '';
  position: absolute;
  inset: -1px;
  border-radius: 13px;
  padding: 1px;
  background: var(--gradient-accent);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  opacity: 0;
  transition: opacity var(--transition-base);
}

.wechat-card:hover::before {
  opacity: 0.5;
}

.wechat-note {
  display: block;
  font-size: 0.75rem;
  color: var(--color-text-muted);
  margin-top: 0.3rem;
}

.cta-section {
  text-align: center;
}

/* ========== 页脚 ========== */
#footer {
  background: var(--color-bg-section);
  padding: var(--space-lg) 0;
}

.footer-line {
  height: 2px;
  background: var(--gradient-accent);
  opacity: 0.3;
}

.footer-content {
  text-align: center;
  padding-top: var(--space-lg);
  color: var(--color-text-muted);
  font-size: var(--font-size-small);
}

/* ========== 滚动揭示动画 ========== */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
  transition-delay: var(--delay, 0s);
}

.reveal.revealed {
  opacity: 1;
  transform: translateY(0);
}

/* ========== 响应式 ========== */

/* 平板 */
@media (max-width: 1023px) {
  .nav-links {
    position: fixed;
    top: 0;
    right: 0;
    width: 260px;
    height: 100vh;
    flex-direction: column;
    background: rgba(15, 21, 56, 0.98);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    padding: calc(var(--nav-height) + var(--space-lg)) var(--space-lg) var(--space-lg);
    gap: var(--space-md);
    transform: translateX(100%);
    transition: transform var(--transition-base);
    z-index: 999;
  }

  #navbar.menu-open .nav-links {
    transform: translateX(0);
  }

  .menu-toggle {
    display: flex;
  }

  .skills-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .advantages-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .contact-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* 手机 */
@media (max-width: 767px) {
  .skills-grid,
  .projects-grid,
  .advantages-grid,
  .contact-grid {
    grid-template-columns: 1fr;
  }

  .hero-content h1 {
    font-size: clamp(1.5rem, 6vw, 2.5rem);
  }

  .hero-subtitle {
    font-size: 0.85rem;
    letter-spacing: 0.02em;
  }

  .card {
    padding: var(--space-sm) var(--space-md);
  }

  .cta-button {
    padding: 0.7rem 1.8rem;
    font-size: 0.9rem;
  }

  .cta-large {
    padding: 0.8rem 1.8rem;
    font-size: 0.9rem;
  }
}

/* ========== 减弱动画 ========== */
@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }

  #particles {
    display: none;
  }

  html {
    scroll-behavior: auto;
  }

  .card,
  .contact-card,
  .cta-button,
  .nav-links a::after {
    transition: none;
  }
}