/* ===== Theme ===== */
:root {
  --bg: #f4efe4;
  --bg-secondary: #efe8d9;
  --bg-card: #faf6ed;
  --text: #2c2a24;
  --text-secondary: #6f695d;
  --border: #ddd3c1;
  --accent: #6c624f;
  --accent-light: #ede4d4;
  --shadow: 0 1px 1px rgba(30, 25, 15, 0.06);
  --shadow-hover: 0 8px 24px rgba(35, 28, 16, 0.1);
  --radius: 12px;
  --radius-sm: 8px;
  --temp-hot: #b35f52;
  --temp-warm: #b48b4f;
  --temp-rising: #9b9752;
  --temp-cool: #7f7d78;
  --font: "Source Serif 4", "Iowan Old Style", "Palatino Linotype", "Book Antiqua", Georgia, serif;
  --font-ui: "Avenir Next", "Segoe UI", "Trebuchet MS", sans-serif;
  --font-mono: "JetBrains Mono", "Cascadia Code", "SF Mono", monospace;
}

[data-theme="dark"] {
  --bg: #1e1b17;
  --bg-secondary: #27231d;
  --bg-card: #24201a;
  --text: #e6decf;
  --text-secondary: #b2a996;
  --border: #3b3429;
  --accent: #d0bf9f;
  --accent-light: #2f291f;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.35);
  --shadow-hover: 0 8px 24px rgba(0, 0, 0, 0.35);
}

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

body {
  font-family: var(--font);
  background:
    radial-gradient(circle at 20% 0%, rgba(255, 255, 255, 0.3), transparent 45%),
    var(--bg);
  color: var(--text);
  line-height: 1.55;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

a:hover {
  text-decoration: underline;
}

/* ===== Header ===== */
.header {
  background: var(--bg-card);
  background: color-mix(in srgb, var(--bg-card) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: 1080px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  gap: 16px;
}

.logo h1 {
  font-size: 1.3rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  white-space: nowrap;
}

.logo .subtitle {
  display: block;
  font-family: var(--font-ui);
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
  margin-top: 1px;
}

.search-box {
  flex: 1;
  max-width: 460px;
}

.search-box input {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 9px 14px;
  background: var(--bg-secondary);
  color: var(--text);
  font-family: var(--font-ui);
  font-size: 0.88rem;
  outline: none;
  transition: border-color 0.2s ease, background 0.2s ease;
}

.search-box input:focus {
  border-color: var(--accent);
  background: var(--bg-card);
}

.theme-toggle {
  margin-left: auto;
  width: 34px;
  height: 34px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--bg-secondary);
  color: var(--text-secondary);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: border-color 0.2s ease, color 0.2s ease, background 0.2s ease;
}

.theme-toggle:hover {
  border-color: var(--accent);
  color: var(--text);
  background: var(--bg-card);
}

.theme-icon {
  font-size: 0.95rem;
  line-height: 1;
}

/* ===== Layout ===== */
.main {
  max-width: 1080px;
  width: 100%;
  margin: 0 auto;
  padding: 22px 20px;
  flex: 1;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  margin-bottom: 12px;
}

.topic-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  flex: 1;
}

.topic-pill {
  padding: 5px 12px;
  border-radius: 999px;
  font-family: var(--font-ui);
  font-size: 0.76rem;
  font-weight: 500;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  cursor: pointer;
  user-select: none;
  transition: border-color 0.2s ease, color 0.2s ease, background 0.2s ease;
}

.topic-pill.active {
  color: var(--text);
  border-color: var(--accent);
  background: var(--bg-card);
}

.sort-controls {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-ui);
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.sort-controls select {
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 6px 12px;
  background: var(--bg-card);
  color: var(--text);
  font-family: var(--font-ui);
  font-size: 0.78rem;
  cursor: pointer;
}

.stats-bar {
  font-family: var(--font-ui);
  font-size: 0.76rem;
  color: var(--text-secondary);
  margin-bottom: 14px;
  border-bottom: 1px solid var(--border);
  padding: 0 0 10px;
}

/* ===== Cards ===== */
.paper-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.loading {
  text-align: center;
  padding: 40px 10px;
  color: var(--text-secondary);
  font-family: var(--font-ui);
}

.paper-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 15px 18px;
  box-shadow: var(--shadow);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.paper-card:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-hover);
}

.paper-card-header {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 7px;
}

.temp-badge {
  flex-shrink: 0;
  min-width: 38px;
  text-align: center;
  border-radius: var(--radius-sm);
  padding: 3px 7px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 600;
  color: #f8f5ed;
}

.temp-hot { background: var(--temp-hot); }
.temp-warm { background: var(--temp-warm); }
.temp-rising { background: var(--temp-rising); color: #21201d; }
.temp-cool { background: var(--temp-cool); }

.paper-title {
  flex: 1;
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.35;
}

.paper-title a {
  color: var(--text);
}

.paper-title a:hover {
  color: var(--accent);
  text-decoration: none;
}

.paper-date {
  flex-shrink: 0;
  white-space: nowrap;
  font-family: var(--font-ui);
  font-size: 0.72rem;
  color: var(--text-secondary);
  margin-top: 1px;
}

.paper-authors {
  font-family: var(--font-ui);
  font-size: 0.78rem;
  color: var(--text-secondary);
  margin-bottom: 6px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.paper-abstract {
  font-size: 0.87rem;
  color: var(--text-secondary);
  line-height: 1.52;
  margin-bottom: 11px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  cursor: pointer;
}

.paper-abstract.expanded {
  display: block;
  -webkit-line-clamp: unset;
}

.paper-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 7px;
}

.paper-topic {
  padding: 2px 8px;
  border-radius: 999px;
  border: 1px solid var(--border);
  font-family: var(--font-ui);
  font-size: 0.67rem;
  color: var(--text-secondary);
}

.paper-venue {
  padding: 2px 8px;
  border-radius: 999px;
  background: var(--accent-light);
  color: var(--accent);
  font-family: var(--font-ui);
  font-size: 0.68rem;
  font-weight: 600;
}

.paper-stat {
  font-family: var(--font-ui);
  font-size: 0.72rem;
  color: var(--text-secondary);
}

.paper-stat strong {
  color: var(--text);
}

.paper-links {
  margin-left: auto;
  display: flex;
  gap: 6px;
}

.paper-link {
  padding: 2px 8px;
  border-radius: 999px;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  font-family: var(--font-ui);
  font-size: 0.71rem;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.paper-link:hover {
  color: var(--accent);
  border-color: var(--accent);
  text-decoration: none;
}

/* ===== Footer / Buttons ===== */
.load-more-wrap {
  text-align: center;
  padding: 20px 0 14px;
}

.load-more-btn {
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg-card);
  color: var(--text-secondary);
  padding: 9px 22px;
  font-family: var(--font-ui);
  font-size: 0.8rem;
  cursor: pointer;
}

.load-more-btn:hover {
  border-color: var(--accent);
  color: var(--text);
}

.footer {
  text-align: center;
  padding: 24px 16px;
  margin-top: 30px;
  border-top: 1px solid var(--border);
  color: var(--text-secondary);
  font-family: var(--font-ui);
  font-size: 0.76rem;
}

.footer p + p {
  margin-top: 4px;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .header-inner {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 10px;
  }

  .logo {
    min-width: 0;
  }

  .search-box {
    grid-column: 1 / -1;
    max-width: none;
  }

  .theme-toggle {
    margin-left: 0;
    justify-self: end;
  }

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

  .sort-controls {
    justify-content: space-between;
  }

  .paper-card-header {
    flex-wrap: wrap;
  }

  .paper-links {
    margin-left: 0;
    width: 100%;
  }
}