/* ============================================================
   Willy Chen — willycecon.com
   Custom styles: MSU Green (#18453B) + white background theme
   ============================================================ */

:root {
  --msu-green:       #18453B;
  --msu-green-hover: #1e5548;
  --msu-green-light: #e8f0ee;
  --white:           #ffffff;
  --body-bg:         #ffffff;
  --text-dark:       #1e1e1e;
  --text-muted:      #6c757d;
  --border-light:    #dee2e6;
}

/* ── Base ── */
body {
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--text-dark);
  background-color: var(--body-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
}

/* ── Navbar ── */
nav.navbar {
  background-color: var(--msu-green);
  padding: 0.75rem 0;
}

nav.navbar .navbar-brand {
  color: var(--white);
  font-weight: 600;
  font-size: 1.15rem;
  letter-spacing: 0.01em;
}

nav.navbar .navbar-brand:hover {
  color: rgba(255, 255, 255, 0.85);
}

nav.navbar .nav-link {
  color: rgba(255, 255, 255, 0.88);
  font-size: 0.93rem;
  padding: 0.4rem 0.85rem;
  border-radius: 4px;
  transition: background-color 0.15s ease, color 0.15s ease;
}

nav.navbar .nav-link:hover,
nav.navbar .nav-link.active {
  color: var(--white);
  background-color: rgba(255, 255, 255, 0.12);
}

nav.navbar .navbar-toggler {
  border-color: rgba(255, 255, 255, 0.4);
}

/* ── Page wrapper ── */
.page-wrapper {
  max-width: 860px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 3rem;
}

/* ── Headings ── */
h1, h2, h3, h4 {
  color: var(--msu-green);
  font-weight: 600;
}

h1 { font-size: 1.75rem; margin-bottom: 1rem; }

h2 {
  font-size: 1.2rem;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.35rem;
  border-bottom: 2px solid var(--msu-green);
}

h3 { font-size: 1.05rem; }

/* ── Links ── */
a {
  color: var(--msu-green);
  text-decoration: none;
}

a:hover {
  color: var(--msu-green-hover);
  text-decoration: underline;
}

/* ── Profile section (home page) ── */
.profile-section {
  display: flex;
  gap: 2.5rem;
  align-items: flex-start;
  margin-top: 1rem;
}

.profile-img {
  width: 210px;
  height: auto;
  border-radius: 10px;
  flex-shrink: 0;
  box-shadow: 0 2px 12px rgba(0,0,0,0.10);
}

.profile-bio p {
  margin-bottom: 0.85rem;
}

@media (max-width: 600px) {
  .profile-section {
    flex-direction: column;
    align-items: center;
  }
  .profile-img {
    width: 160px;
  }
}

/* ── Research page ── */
.paper-entry {
  margin-bottom: 1.4rem;
  padding-bottom: 1.4rem;
  border-bottom: 1px solid var(--border-light);
}

.paper-entry:last-child {
  border-bottom: none;
  margin-bottom: 0;
  padding-bottom: 0;
}

.paper-meta {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

/* ── CV page ── */
.cv-container {
  max-width: 720px;
  margin: 0 auto;
  text-align: center;
}

.cv-embed {
  width: 100%;
  height: 85vh;
  border: 1px solid var(--border-light);
  border-radius: 6px;
  margin-top: 0.75rem;
}

.cv-download-link {
  display: inline-block;
  margin-bottom: 1rem;
  padding: 0.45rem 1.1rem;
  background-color: var(--msu-green);
  color: var(--white);
  border-radius: 5px;
  font-size: 0.93rem;
  font-weight: 500;
  transition: background-color 0.15s ease;
}

.cv-download-link:hover {
  background-color: var(--msu-green-hover);
  color: var(--white);
  text-decoration: none;
}

/* ── Photography page ── */
.flickr-container {
  max-width: 800px;
  margin: 0 auto;
}

.flickr-container img {
  border-radius: 8px;
  width: 100%;
}

/* ── Code ── */
code {
  background-color: var(--msu-green-light);
  color: var(--msu-green);
  padding: 0.15em 0.45em;
  border-radius: 4px;
  font-size: 0.88em;
}

/* ── Footer ── */
footer {
  background-color: var(--msu-green);
  color: rgba(255, 255, 255, 0.8);
  text-align: center;
  padding: 1.4rem 1rem;
  font-size: 0.85rem;
  margin-top: 4rem;
}

footer a {
  color: rgba(255, 255, 255, 0.9);
}

footer a:hover {
  color: var(--white);
  text-decoration: underline;
}

/* ── Utility ── */
img {
  max-width: 100%;
  border-radius: 6px;
}

.text-msu {
  color: var(--msu-green);
}

hr.section-divider {
  border: none;
  border-top: 2px solid var(--msu-green);
  margin: 1.5rem 0;
  opacity: 1;
}