:root {
  --bg:          #dde8f8;
  --accent:      #5b21b6;
  --accent-hi:   #7c3aed;
  --accent-glow: rgba(91, 33, 182, 0.15);
  --green:       #059669;
  --text:        #1e1b4b;
  --text-2:      #3730a3;
  --text-3:      #6d6db3;
  --glass:       rgba(255, 255, 255, 0.55);
  --glass-hi:    rgba(255, 255, 255, 0.75);
  --glass-border:rgba(255, 255, 255, 0.70);
  --glass-shadow:rgba(99,  80, 200, 0.12);
  --font:        'Inter', sans-serif;
  --font-head:   'Space Grotesk', sans-serif;
  --font-mono:   'JetBrains Mono', monospace;
  --radius:      14px;
  --sidebar-w:   264px;
}

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

html, body {
  height: 100%;
  font-family: var(--font);
  color: var(--text);
  overflow: hidden;

  /* Soft lavender-white gradient base */
  background:
    radial-gradient(ellipse 90% 70% at 15%  0%,  rgba(196,181,253,0.55) 0%, transparent 55%),
    radial-gradient(ellipse 70% 55% at 88% 15%,  rgba(147,197,253,0.45) 0%, transparent 50%),
    radial-gradient(ellipse 60% 50% at 50% 100%, rgba(216,180,254,0.40) 0%, transparent 55%),
    radial-gradient(ellipse 80% 80% at 50%  50%, rgba(224,231,255,0.60) 0%, transparent 80%),
    #e8eeff;
}

/* ── Particle canvas ── */
#particles { position: fixed; inset: 0; z-index: 0; opacity: 0.5; }

/* ── Layout ── */
.layout { position: relative; z-index: 1; display: flex; height: 100vh; }

/* ── Sidebar ── */
.sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  background: var(--glass);
  backdrop-filter: blur(28px) saturate(180%);
  -webkit-backdrop-filter: blur(28px) saturate(180%);
  border-right: 1px solid var(--glass-border);
  box-shadow: 2px 0 24px var(--glass-shadow);
  display: flex; flex-direction: column;
  overflow-y: auto; padding: 20px 16px 32px;
  scrollbar-width: thin; scrollbar-color: rgba(99,80,200,0.2) transparent;
}

.sidebar-logo {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 0 24px;
  font-family: var(--font-head);
  font-size: 18px; font-weight: 700;
  color: var(--accent);
}
.logo-icon { font-size: 24px; }

.filter-section { margin-bottom: 22px; }

.filter-label {
  display: block;
  font-size: 10px; font-weight: 700; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--text-3);
  margin-bottom: 8px;
}

.year-range { display: flex; align-items: center; gap: 8px; }
.year-range input {
  width: 80px;
  background: rgba(255,255,255,0.6);
  border: 1px solid var(--glass-border); border-radius: 8px;
  color: var(--text); font-family: var(--font-mono); font-size: 13px;
  padding: 7px 10px; outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}
.year-range input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(91,33,182,0.12);
}
.year-range span { color: var(--text-3); }

.topic-list { display: flex; flex-direction: column; gap: 3px; }

.topic-btn {
  display: flex; align-items: center; gap: 8px;
  padding: 7px 10px; border-radius: 9px;
  border: 1px solid transparent;
  background: transparent; color: var(--text-2);
  font-size: 12.5px; cursor: pointer; text-align: left;
  transition: all 0.15s;
}
.topic-btn:hover {
  background: rgba(255,255,255,0.5);
  color: var(--text);
}
.topic-btn.active {
  background: rgba(91,33,182,0.12);
  border-color: rgba(91,33,182,0.35);
  color: var(--accent);
}
.topic-dot { width: 8px; height: 8px; border-radius: 50%; flex-shrink: 0; }

.filter-select {
  width: 100%;
  background: rgba(255,255,255,0.6);
  border: 1px solid var(--glass-border); border-radius: 8px;
  color: var(--text); font-family: var(--font); font-size: 13px;
  padding: 8px 10px; outline: none; cursor: pointer;
}
.filter-select:focus { border-color: var(--accent); }

.filter-toggle {
  display: flex; align-items: center; gap: 8px;
  font-size: 12.5px; color: var(--text-2); cursor: pointer;
}
.filter-toggle input { accent-color: var(--accent); cursor: pointer; }

.sidebar-stats {
  margin-top: auto; padding-top: 20px;
  border-top: 1px solid rgba(99,80,200,0.18);
  font-size: 11px; color: var(--text-3); line-height: 1.9;
}

/* ── Main ── */
.main { flex: 1; display: flex; flex-direction: column; overflow: hidden; }

/* ── Topbar ── */
.topbar {
  background: var(--glass);
  backdrop-filter: blur(28px) saturate(180%);
  -webkit-backdrop-filter: blur(28px) saturate(180%);
  border-bottom: 1px solid var(--glass-border);
  box-shadow: 0 2px 20px var(--glass-shadow);
  padding: 14px 24px;
  display: flex; flex-direction: column; gap: 10px;
  flex-shrink: 0;
}

.search-wrap {
  display: flex; align-items: center; gap: 10px;
  background: rgba(255,255,255,0.65);
  border: 1px solid var(--glass-border); border-radius: 11px;
  padding: 0 14px;
  transition: border-color 0.2s, box-shadow 0.2s;
}
.search-wrap:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(91,33,182,0.12);
}
.search-icon { font-size: 18px; color: var(--text-3); }

#search {
  flex: 1; background: transparent; border: none; outline: none;
  color: var(--text); font-family: var(--font); font-size: 14px;
  padding: 11px 0;
}
#search::placeholder { color: var(--text-3); }

kbd {
  font-family: var(--font-mono); font-size: 11px;
  color: var(--text-3);
  background: rgba(255,255,255,0.7);
  border: 1px solid rgba(99,80,200,0.2); border-radius: 5px;
  padding: 2px 6px;
}

.stats-row { display: flex; gap: 8px; flex-wrap: wrap; }

.stat-chip {
  font-size: 11.5px; color: var(--text-2);
  background: rgba(255,255,255,0.6);
  border: 1px solid var(--glass-border);
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.8);
  border-radius: 6px; padding: 3px 10px;
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}

/* ── Papers grid ── */
.papers-grid {
  flex: 1; overflow-y: auto;
  padding: 20px 24px 40px;
  display: flex; flex-direction: column; gap: 14px;
  scrollbar-width: thin; scrollbar-color: rgba(99,80,200,0.2) transparent;
}

/* ── Paper card ── */
.card {
  position: relative;
  background: var(--glass-hi);
  backdrop-filter: blur(20px) saturate(160%);
  -webkit-backdrop-filter: blur(20px) saturate(160%);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  padding: 18px 20px;
  /* layered shadow: ambient + top-edge highlight (glass edge trick) */
  box-shadow:
    0 4px 20px var(--glass-shadow),
    inset 0 1px 0 rgba(255,255,255,0.6),
    inset 0 -1px 0 rgba(91,33,182,0.06);
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
  animation: fadeUp 0.3s ease both;
}
.card:hover {
  transform: translateY(-3px);
  box-shadow:
    0 14px 40px rgba(91,33,182,0.16),
    0 0 0 1px rgba(91,33,182,0.22),
    inset 0 1px 0 rgba(255,255,255,0.7),
    inset 0 -1px 0 rgba(91,33,182,0.08);
  border-color: rgba(91,33,182,0.3);
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: translateY(0); }
}

.card-title {
  font-family: var(--font-head);
  font-size: 15px; font-weight: 600;
  color: var(--text); line-height: 1.4;
  margin-bottom: 8px;
}

.card-topics { display: flex; flex-wrap: wrap; gap: 5px; margin-bottom: 9px; }

.badge {
  font-size: 10.5px; font-weight: 500;
  padding: 2px 8px; border-radius: 20px;
  border: 1px solid currentColor;
  background: rgba(255,255,255,0.45);
  opacity: 0.9;
}

.venue-badge {
  font-size: 10.5px; font-weight: 600;
  padding: 2px 10px; border-radius: 20px;
  background: rgba(245, 158, 11, 0.12);
  border: 1px solid rgba(245, 158, 11, 0.5);
  color: #92400e;
  letter-spacing: 0.03em;
}

.card-meta {
  font-size: 12px; color: var(--text-2);
  display: flex; flex-wrap: wrap; align-items: center; gap: 12px;
  margin-bottom: 10px;
  font-variant-numeric: tabular-nums;
}
.card-meta span { display: flex; align-items: center; gap: 4px; }

.card-actions { display: flex; gap: 8px; margin-bottom: 10px; }

.btn {
  display: inline-flex; align-items: center; gap: 5px;
  font-size: 12px; font-weight: 500; padding: 5px 12px;
  border-radius: 7px; border: 1px solid rgba(99,80,200,0.25);
  text-decoration: none; cursor: pointer;
  transition: all 0.15s;
  background: rgba(255,255,255,0.5);
}
.btn-paper {
  background: rgba(91,33,182,0.1); color: var(--accent);
  border-color: rgba(91,33,182,0.35);
}
.btn-paper:hover { background: var(--accent); color: #fff; }
.btn-code {
  background: rgba(5,150,105,0.08); color: var(--green);
  border-color: rgba(5,150,105,0.35);
}
.btn-code:hover { background: var(--green); color: #fff; }

.abstract-toggle {
  font-size: 11.5px; color: var(--text-3);
  cursor: pointer; user-select: none;
  display: inline-flex; align-items: center; gap: 4px;
  transition: color 0.15s;
}
.abstract-toggle:hover { color: var(--accent); }

.abstract-text {
  margin-top: 10px; font-size: 12.5px; color: var(--text-2);
  line-height: 1.7; border-left: 2px solid var(--accent);
  padding-left: 12px;
  /* 3-line clamp when closed */
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 3;
  overflow: hidden;
}
.abstract-text.open {
  display: block;        /* remove line-clamp when expanded */
  -webkit-line-clamp: unset;
  overflow: visible;
}

/* ── Loading / empty ── */
.loading, .empty {
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  height: 100%; gap: 12px;
  color: var(--text-3); font-size: 14px;
}
.hidden { display: none !important; }

.spinner {
  width: 36px; height: 36px;
  border: 2px solid rgba(91,33,182,0.2);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }