:root {
  --bg: #ffffff;
  --bg-alt: #f6f7f9;
  --card: #ffffff;
  --text: #1a1d26;
  --text-muted: #5b6270;
  --border: #e6e8ee;
  --primary: #6366f1;
  --primary-hover: #4f46e5;
  --shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
  --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.12);
  --radius: 14px;
}

[data-theme="dark"] {
  --bg: #0f1117;
  --bg-alt: #161922;
  --card: #1a1e2a;
  --text: #e7e9ef;
  --text-muted: #9aa1b0;
  --border: #2a2f3d;
  --shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
  --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.55);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  transition: background 0.3s ease, color 0.3s ease;
}

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Navbar */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background 0.3s ease, border-color 0.3s ease;
}

[data-theme="dark"] .navbar {
  background: rgba(15, 17, 23, 0.85);
}

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

.brand {
  font-weight: 800;
  font-size: 1.15rem;
  color: var(--primary);
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 28px;
}

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 500;
  transition: color 0.2s ease;
}

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.icon-btn {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-muted);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px;
  border-radius: 8px;
  transition: color 0.2s ease, background 0.2s ease;
}

.icon-btn:hover {
  color: var(--primary);
  background: var(--bg-alt);
}

.icon-btn svg {
  width: 20px;
  height: 20px;
}

.icon-moon {
  display: none;
}

[data-theme="dark"] .icon-sun {
  display: none;
}

[data-theme="dark"] .icon-moon {
  display: block;
}

.menu-btn {
  display: none;
}

/* Hero */
.hero {
  padding: 140px 0 80px;
  text-align: center;
  background: radial-gradient(ellipse at top, rgba(99, 102, 241, 0.12), transparent 60%);
}

.hero-badge {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 999px;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.82rem;
  margin-bottom: 24px;
}

.hero-title {
  font-size: clamp(2.2rem, 5vw, 3.4rem);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 18px;
}

.gradient-text {
  background: linear-gradient(90deg, #6366f1, #8b5cf6, #d946ef);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

.hero-sub {
  color: var(--text-muted);
  font-size: 1.12rem;
  max-width: 520px;
  margin: 0 auto 36px;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-bottom: 56px;
}

.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: 10px;
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 0.2s ease;
}

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

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

.btn-ghost {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}

.btn-ghost:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 56px;
}

.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.stat-num {
  font-size: 2rem;
  font-weight: 800;
  color: var(--primary);
}

.stat-label {
  font-size: 0.86rem;
  color: var(--text-muted);
}

/* Sections */
.section {
  padding: 90px 0;
}

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

.section-title {
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 40px;
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -8px;
  width: 44px;
  height: 4px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--primary), #d946ef);
}

/* About */
.about-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: 48px;
  align-items: start;
}

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

.info-list {
  list-style: none;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--card);
  padding: 8px 20px;
  box-shadow: var(--shadow);
}

.info-list li {
  display: flex;
  justify-content: space-between;
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.92rem;
}

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

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

/* Skills */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

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

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

.skill-card h3 {
  font-size: 1.1rem;
  margin-bottom: 20px;
  color: var(--primary);
}

.skill-bar {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  margin: 12px 0 6px;
}

.skill-name {
  font-weight: 500;
}

.skill-val {
  color: var(--text-muted);
}

.bar-track {
  height: 6px;
  background: var(--bg-alt);
  border-radius: 3px;
  overflow: hidden;
}

.bar-fill {
  display: block;
  height: 100%;
  width: 0;
  border-radius: 3px;
  background: linear-gradient(90deg, var(--primary), #8b5cf6);
  transition: width 1s ease;
}

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

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

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

.project-cover {
  height: 140px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.1rem;
  color: #fff;
  background: linear-gradient(135deg, var(--accent), transparent);
  position: relative;
}

.project-cover::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, transparent 40%, rgba(255, 255, 255, 0.12));
}

.project-cover span {
  position: relative;
  z-index: 1;
}

.project-body {
  padding: 24px;
}

.project-body h3 {
  font-size: 1.05rem;
  margin-bottom: 10px;
}

.project-body p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 16px;
}

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

.project-tags span {
  font-size: 0.75rem;
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  color: var(--text-muted);
}

/* Contact */
.contact-inner {
  text-align: center;
  max-width: 640px;
}

.contact-desc {
  color: var(--text-muted);
  margin-bottom: 36px;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-bottom: 40px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.contact-form input,
.contact-form textarea {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--card);
  color: var(--text);
  font-family: inherit;
  font-size: 0.92rem;
  outline: none;
  transition: border-color 0.2s ease;
}

.contact-form input:focus,
.contact-form textarea:focus {
  border-color: var(--primary);
}

.contact-form textarea {
  resize: vertical;
}

.contact-form .btn {
  align-self: center;
  min-width: 160px;
}

.form-status {
  margin-top: 12px;
  font-size: 0.9rem;
  color: #10b981;
  min-height: 24px;
}

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

.social-link {
  padding: 8px 20px;
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.88rem;
  font-weight: 500;
  transition: all 0.2s ease;
}

.social-link:hover {
  color: var(--primary);
  border-color: var(--primary);
}

/* Footer */
.footer {
  border-top: 1px solid var(--border);
  padding: 28px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* Reveal animation */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* Responsive */
@media (max-width: 860px) {
  .skills-grid,
  .projects-grid {
    grid-template-columns: 1fr 1fr;
  }

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

@media (max-width: 640px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--card);
    border-bottom: 1px solid var(--border);
    padding: 16px 24px;
    gap: 4px;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    padding: 10px 0;
  }

  .menu-btn {
    display: inline-flex;
  }

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

  .hero-stats {
    gap: 32px;
  }

  .form-row {
    grid-template-columns: 1fr;
  }
}