:root {
  --background: #f7f7f7;
  --foreground: #222;
  --header-footer-bg: #2d3a4a;
  --header-footer-fg: #fff;
  --accent: #b71c1c;
  --link: #1a73e8;
  --toggle-bg: #fff;
  --toggle-fg: #222;
  --subtitle: #e0e6ef;
  --heading: #222;
}

body[data-theme='dark'] {
  --background: #181a1b;
  --foreground: #f7f7f7;
  --header-footer-bg: #23272e;
  --header-footer-fg: #fff;
  --accent: #ff5252;
  --link: #8ab4f8;
  --toggle-bg: #23272e;
  --toggle-fg: #fff;
  --subtitle: #b0b8c7;
  --heading: #f7f7f7;
}

body {
  background: var(--background);
  color: var(--foreground);
  margin: 0;
  font-family: 'Segoe UI', Arial, sans-serif;
  min-height: 100vh;
  transition: background 0.3s, color 0.3s;
}

#site-header {
  background: var(--header-footer-bg);
  color: var(--header-footer-fg);
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}

#site-header .header-inner {
  max-width: 600px;
  margin: 0 auto;
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  padding: 1.2rem 1.5rem 1rem 1.5rem;
}

.header-content {
  display: flex;
  flex-direction: column;
  justify-content: center;
  height: 100%;
}

#theme-toggle {
  background: var(--toggle-bg);
  color: var(--toggle-fg);
  border: none;
  border-radius: 50%;
  width: 40px;
  height: 40px;
  font-size: 1.3rem;
  cursor: pointer;
  margin-left: 1rem;
  transition: background 0.3s, color 0.3s;
  box-shadow: 0 1px 4px rgba(0,0,0,0.08);
}

#site-footer {
  background: var(--header-footer-bg);
  color: var(--header-footer-fg);
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  text-align: center;
  padding: 0;
  font-size: 0.95rem;
  z-index: 1000;
  box-shadow: 0 -2px 8px rgba(0,0,0,0.04);
  height: 40px;
  min-height: 40px;
}

.footer-inner {
  max-width: 600px;
  margin: 0 auto;
  padding: 0 1.5rem;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  margin-bottom: 0;
  padding-bottom: 0;
}

#site-footer p {
  margin: 0;
  padding: 0;
  text-align: center;
  width: 100%;
  margin-bottom: 0;
  padding-bottom: 0;
}

main {
  max-width: 600px;
  margin: 0 auto;
  padding: var(--header-height, 110px) 1rem 1rem 1rem;
  padding-bottom: 50px;
}

a {
  color: var(--link);
  text-decoration: none;
  transition: color 0.2s;
}
a:hover {
  color: var(--accent);
}

.back-link {
  display: inline-block;
  margin-bottom: 1.5rem;
  padding-top: 0.5rem;
  color: var(--link);
  font-size: 1rem;
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s;
}
.back-link:hover {
  color: var(--accent);
  text-decoration: underline;
}

.years-list ul {
  list-style: none;
  padding: 0;
  margin: 0;
}
.years-list li {
  margin: 1.2rem 0;
  font-size: 1.2rem;
  display: flex;
  align-items: center;
}
.years-list .count {
  margin-left: 0.7em;
  color: var(--accent);
  font-size: 1rem;
}

.subtitle {
  font-size: 1.1rem;
  font-weight: 400;
  color: var(--subtitle);
  margin: 0.2em 0 0 0;
  opacity: 1;
}

h1, h3, .paper-title {
  color: var(--heading);
}

.paper-card,
.paper-card h2,
.paper-card .paper-title,
.paper-card .paper-meta {
  color: #222;
}
.years-list a {
  font-weight: 600;
  color: var(--heading);
  text-decoration: none;
}
.years-list a:hover {
  color: var(--accent);
}
.count {
  color: #888;
  font-size: 0.95em;
  margin-left: 0.5em;
}
.papers-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}
.paper-card {
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
  padding: 1.2rem 1.5rem;
  border: 1px solid #e0e0e0;
}
.paper-title {
  margin: 0 0 0.3em 0;
  font-size: 1.2rem;
  font-weight: 600;
}
.paper-meta {
  color: #555;
  font-size: 1rem;
  margin-bottom: 0.7em;
}
.pdf-link {
  display: inline-flex;
  align-items: center;
  background: #f3f7fa;
  border-radius: 4px;
  padding: 0.2em 0.7em 0.2em 0.4em;
  color: #0074d9;
  text-decoration: none;
  font-weight: 500;
  font-size: 1rem;
  transition: background 0.2s;
}
.pdf-link:hover {
  background: #e6f0fa;
  color: #005fa3;
}
.pdf-icon {
  width: 1.1em;
  height: 1.5em;
  margin-right: 0.4em;
  vertical-align: middle;
}
footer {
  text-align: center;
  color: #888;
  font-size: 0.95rem;
  margin: 3rem 0 1rem 0;
}
@media (max-width: 600px) {
  main {
    padding: var(--header-height, 110px) 0.3rem 1rem 0.3rem;
  }
  .paper-card {
    padding: 1rem 0.7rem;
  }
  #site-header .header-inner {
    flex-direction: column;
    align-items: flex-start;
    padding: 0.7rem 0.7rem 0.5rem 0.7rem;
  }
  .header-content {
    width: 100%;
    align-items: flex-start;
  }
  h1 {
    font-size: 1.3rem;
    margin-bottom: 0.2em;
    word-break: break-word;
  }
  .subtitle {
    font-size: 0.95rem;
    margin-top: 0.1em;
  }
  #theme-toggle {
    width: 34px;
    height: 34px;
    font-size: 1.1rem;
    margin-left: 0;
    margin-top: 0.5rem;
    align-self: flex-end;
  }
}