/* Wenlan Zhang - Personal Website Styles */
@import url('https://fonts.googleapis.com/css2?family=DM+Sans:ital,opsz,wght@0,9..40,400;0,9..40,500;0,9..40,600;0,9..40,700;1,9..40,400&family=DM+Serif+Display&display=swap');

:root {
  --color-bg: #faf9f7;
  --color-surface: #ffffff;
  --color-text: #2d2a26;
  --color-text-muted: #6b6560;
  --color-accent: #068194;
  --color-accent-hover: #056a7a;
  --color-border: #e8e6e3;
  --color-card-shadow: rgba(45, 42, 38, 0.06);
  --font-sans: 'DM Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-serif: 'DM Serif Display', Georgia, serif;
  --max-width: 720px;
  --nav-height: 64px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-sans);
  font-size: 1.05rem;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
}

/* Navigation */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
}

.nav-brand {
  font-family: var(--font-sans);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-text);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-brand img {
  height: 36px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  flex-wrap: wrap;
}

.nav-links a {
  padding: 0.5rem 0.75rem;
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  border-radius: 6px;
  transition: color 0.2s, background 0.2s;
}

.nav-links a:hover {
  color: var(--color-accent);
  background: rgba(6, 129, 148, 0.08);
}

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

.nav-social {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-social a {
  color: var(--color-text-muted);
  padding: 0.5rem;
  text-decoration: none;
  transition: color 0.2s;
}

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

/* Main content */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 3rem 1.5rem 4rem;
}

/* About block - Home page */
.about-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  margin-bottom: 3rem;
}

.about-image {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  object-fit: cover;
  margin-bottom: 1.5rem;
  border: 3px solid var(--color-border);
  box-shadow: 0 8px 32px var(--color-card-shadow);
}

.about-links {
  display: flex;
  gap: 1rem;
  margin-bottom: 2rem;
}

.about-links a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 1.5rem;
  transition: color 0.2s, transform 0.2s;
}

.about-links a:hover {
  color: var(--color-accent);
  transform: translateY(-2px);
}

.bio {
  text-align: justify;
  font-size: 1em;
}

.bio p {
  margin-bottom: 1rem;
}

.bio a {
  color: var(--color-accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s;
}

.bio a:hover {
  border-bottom-color: var(--color-accent);
}

.bio + .bio {
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid var(--color-border);
}

/* Page titles - main "Projects", "Experience", etc. (keep the display font) */
.page-title {
  font-family: var(--font-sans);
  font-size: 2rem;
  font-weight: 400;
  margin: 0 0 2rem;
  color: var(--color-text);
}

/* Section headings */
h2 {
  font-family: var(--font-sans);
  font-size: 1.25rem;
  font-weight: 600;
  margin: 2.5rem 0 1rem;
  color: var(--color-text);
}

h2:first-of-type {
  margin-top: 0;
}

h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 1.5rem 0 0.75rem;
  color: var(--color-text);
}

/* Cards / Project blocks */
.card {
  background: var(--color-surface);
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 2rem;
  box-shadow: 0 2px 12px var(--color-card-shadow);
  border: 1px solid var(--color-border);
}

.card-meta {
  text-align: center;
  font-style: italic;
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-bottom: 1rem;
}

.card-meta a {
  color: var(--color-accent);
  text-decoration: none;
}

.card-meta a:hover {
  text-decoration: underline;
}

.card img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  display: block;
  margin: 0 auto 1rem;
  cursor: pointer;
  transition: opacity 0.2s;
}

.card img:hover {
  opacity: 0.92;
}

.card-links {
  text-align: center;
  margin-top: 1rem;
}

.card-links a {
  color: var(--color-accent);
  text-decoration: none;
  margin: 0 0.5rem;
}

.card-links a:hover {
  text-decoration: underline;
}

ul {
  margin: 0.5rem 0 1rem;
  padding-left: 1.25rem;
}

li {
  margin-bottom: 0.35rem;
}

/* Experience / Education items */
.exp-item {
  margin-bottom: 2.5rem;
  padding-bottom: 2.5rem;
  border-bottom: 1px solid var(--color-border);
}

.exp-item:last-child {
  border-bottom: none;
  margin-bottom: 0;
  padding-bottom: 0;
}

.exp-item img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  margin-bottom: 1rem;
  cursor: pointer;
}

.exp-item h2 {
  margin-top: 0;
}

.exp-links {
  margin: 0.5rem 0 1rem;
}

.exp-links a {
  color: var(--color-accent);
  text-decoration: none;
  margin-right: 1rem;
}

.exp-links a:hover {
  text-decoration: underline;
}

/* Presentation cards */
.pres-card {
  background: var(--color-surface);
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 2rem;
  box-shadow: 0 2px 12px var(--color-card-shadow);
  border: 1px solid var(--color-border);
}

.pres-card img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  margin-bottom: 1rem;
}

.pres-card p {
  margin: 0.5rem 0;
  font-size: 0.95rem;
}

.pres-card .pres-title {
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.pres-card a {
  color: var(--color-accent);
  text-decoration: none;
}

.pres-card a:hover {
  text-decoration: underline;
}

/* CV page */
.cv-download {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  background: var(--color-accent);
  color: white !important;
  text-decoration: none;
  border-radius: 8px;
  font-weight: 500;
  margin-bottom: 1.5rem;
  transition: background 0.2s;
}

.cv-download:hover {
  background: var(--color-accent-hover);
}

.cv-embed {
  position: relative;
  padding-bottom: 129%;
  height: 0;
  overflow: hidden;
  max-width: 100%;
  border-radius: 8px;
  border: 1px solid var(--color-border);
}

.cv-embed iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

/* Footer */
footer {
  text-align: center;
  padding: 2rem 1.5rem;
  color: var(--color-text-muted);
  font-size: 0.9rem;
  border-top: 1px solid var(--color-border);
}

/* Divider */
hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 2rem 0;
}

/* Responsive */
@media (max-width: 768px) {
  .nav {
    flex-wrap: wrap;
    height: auto;
    padding: 1rem;
  }

  .nav-links {
    order: 3;
    width: 100%;
    margin-top: 0.5rem;
    padding-top: 0.5rem;
    border-top: 1px solid var(--color-border);
  }

  .nav-social {
    margin-left: auto;
  }

  main {
    padding: 2rem 1rem 3rem;
  }

  .about-image {
    width: 140px;
    height: 140px;
  }
}