/* ============================================================
   CSS CUSTOM PROPERTIES — edit these to theme your site!
   TODO: Try asking Copilot to suggest a color palette for you.
   ============================================================ */
:root {
  --color-bg: #ffffff;
  --color-bg-alt: #ffffff;
  --color-text: #000000;
  --color-text-muted: #000000;
  --color-accent: #f97316;
  --color-accent-hover: #ea580c;
  --color-border: #ff8800;
  --font-main: 'Segoe UI', system-ui, sans-serif;
  --radius: 10px;
  --shadow: 0 2px 12px rgb(0, 0, 0);
  --transition: 0.2s ease;
}

body[data-theme='dark'] {
  --color-bg: #111111;
  --color-bg-alt: #1b1b1b;
  --color-text: #ffffff;
  --color-text-muted: #e5e5e5;
  --color-border: #ffffff;
  --shadow: 0 2px 12px rgba(255, 255, 255, 0.12);
}

/* TODO: Add a [data-theme="dark"] block here for dark mode.
   Copilot can generate this for you — try:
   "Add a dark mode theme using CSS custom properties" */

/* ============================================================
   RESET & BASE
   ============================================================ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-main);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
}

.section,
.section-alt,
.about-text,
.project-card,
.contact-intro,
footer {
  color: var(--color-text);
}

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

a:hover {
  color: var(--color-text);
}

/* ============================================================
   NAVIGATION
   ============================================================ */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 2rem;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow);
}

.nav-logo {
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--color-text);
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 2rem;
}

.nav-links a {
  color: var(--color-text);
  font-weight: 500;
}

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

.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  cursor: pointer;
  user-select: none;
  font-weight: 600;
  color: var(--color-text);
}

.theme-toggle-label {
  font: inherit;
  color: inherit;
}

.theme-toggle-switch {
  position: relative;
  width: 3.4rem;
  height: 1.9rem;
  flex: 0 0 auto;
}

.theme-toggle-input {
  position: absolute;
  opacity: 0;
  width: 1px;
  height: 1px;
  pointer-events: none;
}

.theme-toggle-track {
  position: absolute;
  inset: 0;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  transition: background var(--transition), border-color var(--transition);
}

.theme-toggle-thumb {
  position: absolute;
  top: 0.18rem;
  left: 0.18rem;
  width: 1.45rem;
  height: 1.45rem;
  border-radius: 50%;
  background: #ffffff;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
  transition: transform var(--transition), background var(--transition);
}

.theme-toggle-input:checked + .theme-toggle-track {
  background: var(--color-accent);
  border-color: var(--color-accent);
}

.theme-toggle-input:checked + .theme-toggle-track .theme-toggle-thumb {
  transform: translateX(1.5rem);
}

.theme-toggle-input:focus-visible + .theme-toggle-track {
  outline: 2px solid var(--color-text);
  outline-offset: 3px;
}

body[data-theme='dark'] .theme-toggle-track {
  background: #2a2a2a;
}

/* TODO: The nav isn't responsive on mobile yet.
   Ask Copilot: "Make this navbar collapse into a hamburger menu on small screens" */

/* ============================================================
   HERO
   ============================================================ */
.hero {
  min-height: 80vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 4rem 2rem;
  background:
    linear-gradient(rgba(0, 0, 0, 0.55), rgba(0, 0, 0, 0.55)),
    url("chinagif.webp") center/cover no-repeat;
  color: #ffffff;
  border-bottom: 2px solid #000;
}

.hero-content {
  max-width: 700px;
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
  margin-bottom: 1rem;
  line-height: 1.2;
  color: #ffffff;
  text-shadow: 0 2px 8px rgba(0, 0, 0, 0.85);
  min-height: 1.4em;
}

.hero-typing {
  display: inline-block;
  min-width: 1ch;
}

.hero-cursor {
  display: inline-block;
  margin-left: 0.05em;
  color: #f97316;
  animation: cursorBlink 0.8s steps(1) infinite;
}

.hero-word.highlight {
  color: #f97316;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: #ffffff;
  text-shadow: 0 2px 8px rgba(0, 0, 0, 0.85);
  margin-bottom: 2rem;
  animation: heroWordRise 1s ease-out 0.8s both;
}

@keyframes cursorBlink {
  50% {
    opacity: 0;
  }
}

/* ============================================================
   BUTTONS
   ============================================================ */
.btn {
  display: inline-block;
  padding: 0.75rem 1.75rem;
  background: var(--color-accent);
  color: #ffffff !important;
  border-radius: var(--radius);
  font-weight: 600;
  transition: background var(--transition), transform var(--transition);
}

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

.btn-outline {
  background: transparent;
  color: #ffffff !important;
  border: 2px solid var(--color-accent);
}

.btn-outline:hover {
  background: var(--color-accent);
  color: #ffffff !important;
}

/* ============================================================
   SECTIONS
   ============================================================ */
.section {
  padding: 5rem 2rem;
  max-width: 1000px;
  margin: 0 auto;
  border-top: 2px solid #000;
}

.section-alt {
  background: var(--color-bg-alt);
  max-width: 100%;
  padding: 5rem 2rem;
  border-top: 2px solid #000;
}

.section-alt > * {
  max-width: 1000px;
  margin: 0 auto;
}

h2 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 2rem;
  position: relative;
  display: inline-block;
}

h2::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 0;
  width: 40px;
  height: 4px;
  background: var(--color-text);
  border-radius: 2px;
}

/* ============================================================
   ABOUT
   ============================================================ */
.about-grid {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 3rem;
  align-items: start;
}

.about-text p + p {
  margin-top: 1rem;
}

.avatar-placeholder {
  width: 160px;
  height: 160px;
  border-radius: 50%;
  background: var(--color-bg-alt);
  border: 3px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
}

.profile-photo {
  width: 160px;
  height: 160px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--color-border);
}

/* ============================================================
   PROJECTS
   ============================================================ */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
}

.project-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition);
}

.project-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
}

body:not([data-theme='dark']) .project-card:hover {
  border-color: #22c55e;
  background: #f0fdf4;
  box-shadow: 0 8px 24px rgba(34, 197, 94, 0.2);
}

.project-card h3 {
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
  color: var(--color-text);
}

.project-card p {
  color: var(--color-text);
  font-size: 0.95rem;
  margin-bottom: 1rem;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1rem;
}

.tag {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.2rem 0.6rem;
  background: #000000;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  color: #ffffff !important;
}

.project-links {
  display: flex;
  gap: 0.75rem;
}

.project-links a {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-text);
}

body[data-theme='dark'] .theme-toggle,
body[data-theme='dark'] .btn,
body[data-theme='dark'] .btn-outline,
body[data-theme='dark'] .project-links a,
body[data-theme='dark'] .nav-links a,
body[data-theme='dark'] .nav-logo {
  color: #ffffff !important;
}

/* ============================================================
   SKILLS
   ============================================================ */
.skills-container {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.skill-badge {
  padding: 0.5rem 1rem;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text);
}

/* ============================================================
   CONTACT
   ============================================================ */
.contact-intro {
  color: var(--color-text);
  margin-bottom: 2rem;
  font-size: 1.1rem;
}

.contact-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 1rem;
  margin-top: 0.5rem;
}

.contact-btn {
  width: 4.25rem;
  height: 4.25rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: var(--color-bg);
  border: 2px solid var(--color-border);
  color: var(--color-text);
  box-shadow: var(--shadow);
  transition: transform var(--transition), background var(--transition), color var(--transition), border-color var(--transition);
  flex: 0 0 auto;
}

.contact-btn:hover {
  transform: translateY(-3px) scale(1.04);
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #ffffff;
}

.contact-icon {
  width: 1.6rem;
  height: 1.6rem;
  display: block;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ============================================================
   FOOTER
   ============================================================ */
footer {
  text-align: center;
  padding: 2rem;
  color: var(--color-text);
  font-size: 0.875rem;
  border-top: 1px solid var(--color-border);
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 768px) {
  .navbar {
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
    padding: 1rem;
  }

  .nav-links {
    flex-wrap: wrap;
    gap: 1rem;
  }

  .hero {
    min-height: auto;
    padding: 3.5rem 1rem;
  }

  .hero-title {
    font-size: clamp(1.8rem, 7vw, 2.6rem);
  }

  .hero-subtitle {
    font-size: 1rem;
  }

  .section,
  .section-alt {
    padding: 3.5rem 1rem;
  }

  .about-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

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

  .project-links {
    flex-direction: column;
    align-items: stretch;
  }

  .avatar-placeholder {
    width: 100px;
    height: 100px;
  }

  .profile-photo {
    width: 100px;
    height: 100px;
  }
}