/* ============================================================
   个人网站 - 主样式表
   简约高级风格 · 响应式布局 · 轻量动画
   修改颜色主题请直接替换下方的 CSS 变量
   ============================================================ */

/* ---------- CSS 变量（主题色配置） ---------- */
:root {
  /* 主色调 */
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-primary-light: #3b82f6;

  /* 文字 */
  --color-text: #1e293b;
  --color-text-light: #64748b;
  --color-text-white: #ffffff;

  /* 背景 */
  --color-bg: #ffffff;
  --color-bg-alt: #f8fafc;
  --color-bg-dark: #0f172a;

  /* 边框 & 分割线 */
  --color-border: #e2e8f0;

  /* 阴影 */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.1);

  /* 圆角 */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;

  /* 间距 */
  --container-width: 1100px;
  --section-padding: 100px;

  /* 字体 */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
               "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Consolas", monospace;

  /* 过渡 */
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

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

a {
  color: inherit;
  text-decoration: none;
}

ul { list-style: none; }

img {
  max-width: 100%;
  display: block;
}

input, textarea, button {
  font: inherit;
  border: none;
  outline: none;
}

/* ---------- 通用容器 ---------- */
.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Section 通用 ---------- */
.section {
  padding: var(--section-padding) 0;
}

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

.section-title {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 12px;
  letter-spacing: -0.02em;
}

.section-subtitle {
  text-align: center;
  color: var(--color-text-light);
  margin-bottom: 48px;
  font-size: 1rem;
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition);
  border: 2px solid transparent;
}

.btn-primary {
  background: var(--color-primary);
  color: var(--color-text-white);
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

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

.btn-outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  transform: translateY(-1px);
}

.btn-sm {
  padding: 6px 16px;
  font-size: 0.85rem;
}

.btn-full {
  width: 100%;
}

/* ==================== 导航栏 ==================== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: all var(--transition);
}

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

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

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--color-primary);
  letter-spacing: -0.03em;
}

.nav-list {
  display: flex;
  gap: 32px;
}

.nav-link {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--color-text-light);
  transition: color var(--transition);
  position: relative;
}

.nav-link::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width var(--transition);
}

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

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

/* 移动端菜单 */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  cursor: pointer;
  padding: 4px;
}

.menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  transition: all var(--transition);
  border-radius: 2px;
}

.menu-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}
.menu-toggle.active span:nth-child(2) {
  opacity: 0;
}
.menu-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ==================== Hero 首页 ==================== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, #f0f5ff 0%, #f8fafc 50%, #fff 100%);
}

.hero-content {
  text-align: center;
  position: relative;
  z-index: 1;
  padding-top: 64px;
}

.hero-greeting {
  font-size: 1.1rem;
  color: var(--color-primary);
  font-weight: 500;
  margin-bottom: 8px;
}

.hero-name {
  font-size: 3.5rem;
  font-weight: 800;
  letter-spacing: 0.15em;
  margin-bottom: 16px;
  background: linear-gradient(135deg, var(--color-primary), #7c3aed);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-tagline {
  font-size: 1.25rem;
  color: var(--color-text);
  font-weight: 500;
  margin-bottom: 12px;
}

.hero-desc {
  font-size: 1rem;
  color: var(--color-text-light);
  line-height: 1.8;
  margin-bottom: 32px;
}

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

/* Hero 背景装饰 */
.hero-bg-decor {
  position: absolute;
  top: -20%;
  right: -10%;
  width: 500px;
  height: 500px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.06) 0%, transparent 70%);
  pointer-events: none;
}

/* ==================== 关于我 ==================== */
.about-grid {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 60px;
  align-items: start;
  margin-top: 48px;
}

.avatar-placeholder {
  width: 200px;
  height: 200px;
  border-radius: 50%;
  overflow: hidden;
  background: var(--color-bg-alt);
  border: 4px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto;
}

/* 如果有真实头像，将下方注释打开，并把图片放到 images/avatar.jpg */
/*
.about-avatar img {
  width: 200px;
  height: 200px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid var(--color-border);
}
*/

.about-text h3 {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.about-text p {
  color: var(--color-text-light);
  margin-bottom: 12px;
  max-width: 600px;
}

.about-info {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 24px;
  max-width: 500px;
}

.info-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.info-label {
  font-size: 0.85rem;
  color: var(--color-text-light);
}

.info-value {
  font-weight: 600;
  color: var(--color-text);
}

/* ==================== 技能 ==================== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 48px;
}

.skill-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 32px 28px;
  text-align: center;
  transition: all var(--transition);
}

.skill-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary-light);
}

.skill-icon {
  width: 48px;
  height: 48px;
  margin: 0 auto 16px;
  color: var(--color-primary);
}

.skill-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
}

.skill-tags li {
  background: var(--color-bg-alt);
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.85rem;
  color: var(--color-text-light);
  border: 1px solid var(--color-border);
}

/* ==================== 项目 ==================== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  margin-top: 48px;
}

.project-card {
  background: var(--color-bg);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  overflow: hidden;
  transition: all var(--transition);
}

.project-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
}

.project-img {
  width: 100%;
  aspect-ratio: 16 / 10;
  overflow: hidden;
  background: var(--color-bg-alt);
}

.project-img-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  color: var(--color-text-light);
  font-size: 0.85rem;
}

.project-img-placeholder svg {
  width: 40px;
  height: 40px;
}

/* 真实项目截图替换方式：将图片放到 images/ 目录，然后在 HTML 的 .project-img 中替换为 <img> */

.project-info {
  padding: 20px 24px 24px;
}

.project-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.project-desc {
  font-size: 0.9rem;
  color: var(--color-text-light);
  margin-bottom: 14px;
  line-height: 1.6;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 16px;
}

.project-tech span {
  background: #eff6ff;
  color: var(--color-primary);
  font-size: 0.78rem;
  padding: 2px 10px;
  border-radius: 4px;
  font-weight: 500;
}

.project-links {
  display: flex;
  gap: 10px;
}

/* ==================== 联系我 ==================== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: 60px;
  margin-top: 48px;
}

.contact-info-list {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px 20px;
  background: var(--color-bg);
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
}

.contact-icon {
  width: 24px;
  height: 24px;
  color: var(--color-primary);
  flex-shrink: 0;
}

.contact-item span {
  font-weight: 500;
  color: var(--color-text);
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 14px 16px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  transition: all var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

.form-hint {
  margin-top: 12px;
  font-size: 0.8rem;
  color: var(--color-text-light);
}

.form-hint a {
  color: var(--color-primary);
  text-decoration: underline;
}

/* ==================== 底部 ==================== */
.footer {
  background: var(--color-bg-dark);
  color: var(--color-text-white);
  padding: 40px 0;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.footer-social {
  display: flex;
  gap: 16px;
}

.social-link {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  transition: all var(--transition);
  color: #94a3b8;
}

.social-link svg {
  width: 20px;
  height: 20px;
}

.social-link:hover {
  color: var(--color-text-white);
  background: rgba(255, 255, 255, 0.1);
}

.footer-copy {
  font-size: 0.85rem;
  color: #64748b;
}

/* ==================== 返回顶部按钮 ==================== */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-primary);
  color: var(--color-text-white);
  cursor: pointer;
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all var(--transition);
  z-index: 999;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top svg {
  width: 20px;
  height: 20px;
}

.back-to-top:hover {
  background: var(--color-primary-dark);
  transform: translateY(-3px);
}

/* ============================================================
   动画
   ============================================================ */

/* 初始状态：淡入 + 上移 */
.fade-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-up.reveal {
  opacity: 1;
  transform: translateY(0);
}

/* 延迟依次出现 */
.delay-1 { transition-delay: 0.1s; }
.delay-2 { transition-delay: 0.2s; }
.delay-3 { transition-delay: 0.3s; }
.delay-4 { transition-delay: 0.4s; }

/* ============================================================
   响应式（移动端适配）
   ============================================================ */

/* 平板 */
@media (max-width: 1024px) {
  .skills-grid,
  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .contact-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
}

/* 手机 */
@media (max-width: 768px) {
  :root {
    --section-padding: 64px;
  }

  .hero-name {
    font-size: 2.5rem;
    letter-spacing: 0.1em;
  }

  .hero-tagline {
    font-size: 1.1rem;
  }

  .section-title {
    font-size: 1.6rem;
  }

  /* 手机导航 */
  .nav {
    position: fixed;
    top: 0;
    right: -100%;
    width: 70%;
    max-width: 300px;
    height: 100vh;
    background: var(--color-bg);
    padding: 80px 32px 32px;
    transition: right var(--transition);
    box-shadow: var(--shadow-lg);
    z-index: 999;
  }

  .nav.active {
    right: 0;
  }

  .nav-list {
    flex-direction: column;
    gap: 24px;
  }

  .nav-link {
    font-size: 1.1rem;
  }

  .menu-toggle {
    display: flex;
    position: relative;
    z-index: 1000;
  }

  /* 关于我 */
  .about-grid {
    grid-template-columns: 1fr;
    gap: 32px;
    text-align: center;
  }

  .about-info {
    grid-template-columns: 1fr;
    max-width: none;
  }

  .about-text p {
    max-width: none;
  }

  /* 技能 & 项目改为单列 */
  .skills-grid,
  .projects-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  /* 底部 */
  .footer-inner {
    flex-direction: column;
    gap: 16px;
    text-align: center;
  }

  .back-to-top {
    bottom: 20px;
    right: 20px;
  }
}