:root {
  --bg: #05070f;
  --bg-2: #0a0f1e;
  --panel: rgba(18, 24, 44, 0.6);
  --panel-solid: #111830;
  --stroke: rgba(120, 150, 220, 0.18);
  --stroke-strong: rgba(120, 160, 255, 0.4);
  --text: #e7edf9;
  --muted: #9aa8c6;
  --faint: #6b7896;
  --accent: #35e0c8;
  --accent-2: #6c7bff;
  --accent-3: #b16cff;
  --glow: 0 0 30px rgba(53, 224, 200, 0.25);
  --radius: 18px;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
}

:root[data-theme='light'] {
  --bg: #eef2fb;
  --bg-2: #e4ebf7;
  --panel: rgba(255, 255, 255, 0.72);
  --panel-solid: #ffffff;
  --stroke: rgba(60, 90, 160, 0.16);
  --stroke-strong: rgba(60, 100, 220, 0.35);
  --text: #10192e;
  --muted: #48587a;
  --faint: #7a8aa8;
  --glow: 0 0 30px rgba(53, 200, 180, 0.18);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
  overflow-x: hidden;
  min-height: 100vh;
}

/* Ambient background */
.aurora {
  position: fixed; inset: -20% -10% auto -10%; height: 80vh; z-index: -2;
  background:
    radial-gradient(50% 60% at 20% 20%, rgba(108, 123, 255, 0.35), transparent 70%),
    radial-gradient(45% 55% at 80% 10%, rgba(53, 224, 200, 0.28), transparent 70%),
    radial-gradient(40% 50% at 60% 60%, rgba(177, 108, 255, 0.22), transparent 70%);
  filter: blur(30px);
  animation: drift 18s ease-in-out infinite alternate;
}
@keyframes drift {
  from { transform: translate3d(-2%, -1%, 0) scale(1); }
  to { transform: translate3d(3%, 2%, 0) scale(1.08); }
}
.grid-overlay {
  position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background-image:
    linear-gradient(var(--stroke) 1px, transparent 1px),
    linear-gradient(90deg, var(--stroke) 1px, transparent 1px);
  background-size: 46px 46px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 30%, transparent 75%);
  opacity: 0.5;
}

/* Topbar */
.topbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 28px;
  backdrop-filter: blur(14px);
  background: linear-gradient(to bottom, rgba(5, 7, 15, 0.7), transparent);
  border-bottom: 1px solid var(--stroke);
}
:root[data-theme='light'] .topbar { background: linear-gradient(to bottom, rgba(238, 242, 251, 0.8), transparent); }
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
  width: 42px; height: 42px; display: grid; place-items: center;
  font-size: 22px; border-radius: 12px;
  background: linear-gradient(135deg, var(--accent-2), var(--accent));
  color: #fff; box-shadow: var(--glow);
}
.brand-text { display: flex; flex-direction: column; line-height: 1.1; }
.brand-name { font-weight: 800; font-size: 19px; letter-spacing: 0.3px; }
.brand-sub { font-size: 11px; color: var(--muted); letter-spacing: 1.5px; text-transform: uppercase; }
.top-nav { display: flex; align-items: center; gap: 22px; }
.top-nav a { color: var(--muted); text-decoration: none; font-size: 14px; font-weight: 500; transition: color 0.2s; }
.top-nav a:hover, .top-nav a.active { color: var(--text); }
.theme-toggle {
  background: var(--panel); border: 1px solid var(--stroke); color: var(--text);
  width: 38px; height: 38px; border-radius: 10px; cursor: pointer; font-size: 16px;
  transition: border-color 0.2s, transform 0.2s;
}
.theme-toggle:hover { border-color: var(--stroke-strong); transform: rotate(15deg); }

/* Hero */
.hero { padding: 60px 24px 30px; }
.hero-inner { max-width: 900px; margin: 0 auto; text-align: center; }
.badge {
  display: inline-block; font-size: 12.5px; letter-spacing: 0.5px;
  color: var(--accent); padding: 6px 14px; border-radius: 999px;
  border: 1px solid var(--stroke-strong); background: var(--panel);
  margin-bottom: 22px;
}
.hero h1 { font-size: clamp(30px, 5.4vw, 54px); line-height: 1.08; margin: 0 0 16px; font-weight: 800; letter-spacing: -1px; }
.grad {
  background: linear-gradient(100deg, var(--accent), var(--accent-2) 50%, var(--accent-3));
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.lede { font-size: clamp(15px, 2vw, 18px); color: var(--muted); max-width: 640px; margin: 0 auto 30px; }

/* Search */
.search-shell { max-width: 780px; margin: 0 auto; position: relative; }
.search-bar {
  display: flex; align-items: center; gap: 10px;
  background: var(--panel); border: 1px solid var(--stroke-strong);
  border-radius: 16px; padding: 8px 8px 8px 18px;
  backdrop-filter: blur(14px); box-shadow: var(--glow);
  transition: border-color 0.2s, box-shadow 0.2s;
}
.search-bar:focus-within { border-color: var(--accent); box-shadow: 0 0 40px rgba(53, 224, 200, 0.35); }
.search-icon { font-size: 22px; color: var(--muted); }
#q { flex: 1; background: transparent; border: none; outline: none; color: var(--text); font-size: 16px; font-family: var(--font); padding: 12px 4px; }
#q::placeholder { color: var(--faint); }
.go-btn {
  border: none; cursor: pointer; color: #04121a; font-weight: 700; font-size: 15px;
  padding: 12px 26px; border-radius: 12px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  transition: transform 0.15s, filter 0.2s;
}
.go-btn:hover { transform: translateY(-1px); filter: brightness(1.08); }
.go-btn:active { transform: translateY(0); }

.suggest {
  position: absolute; top: 66px; left: 0; right: 0; z-index: 40;
  background: var(--panel-solid); border: 1px solid var(--stroke);
  border-radius: 12px; overflow: hidden; box-shadow: 0 20px 50px rgba(0,0,0,0.4);
}
.suggest button {
  display: block; width: 100%; text-align: left; background: none; border: none;
  color: var(--text); padding: 11px 18px; cursor: pointer; font-size: 14px; font-family: var(--font);
}
.suggest button:hover { background: var(--panel); color: var(--accent); }

.filters { margin-top: 18px; }
.chip-group { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; }
.chip {
  background: var(--panel); border: 1px solid var(--stroke); color: var(--muted);
  padding: 7px 14px; border-radius: 999px; cursor: pointer; font-size: 13px; font-family: var(--font);
  transition: all 0.2s;
}
.chip:hover { color: var(--text); border-color: var(--stroke-strong); transform: translateY(-1px); }

.advanced {
  margin-top: 18px; display: flex; flex-wrap: wrap; gap: 14px; align-items: flex-end; justify-content: center;
  padding: 16px; background: var(--panel); border: 1px solid var(--stroke); border-radius: 14px;
}
.adv-field { display: flex; flex-direction: column; gap: 5px; text-align: left; }
.adv-field label { font-size: 11px; text-transform: uppercase; letter-spacing: 0.8px; color: var(--faint); }
.adv-field select, .adv-field input {
  background: var(--bg-2); border: 1px solid var(--stroke); color: var(--text);
  padding: 8px 12px; border-radius: 9px; font-size: 14px; font-family: var(--font); min-width: 120px;
}
.adv-field input[type=number] { width: 100px; }
.oa-toggle { display: flex; align-items: center; gap: 8px; font-size: 14px; color: var(--muted); cursor: pointer; padding-bottom: 8px; }
.oa-toggle input { width: 16px; height: 16px; accent-color: var(--accent); }

/* Results */
.results-wrap { max-width: 940px; margin: 24px auto 0; padding: 0 24px; }
.results-head { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px; margin-bottom: 18px; }
.results-meta { font-size: 15px; color: var(--muted); }
.results-meta b { color: var(--text); }
.source-pills { display: flex; flex-wrap: wrap; gap: 6px; }
.pill {
  font-size: 11.5px; padding: 4px 10px; border-radius: 999px;
  border: 1px solid var(--stroke); background: var(--panel); color: var(--muted);
}
.pill.err { color: #ff8a8a; border-color: rgba(255,120,120,0.3); }
.pill b { color: var(--accent); }

/* View toggle */
.view-toggle { display: flex; gap: 6px; align-items: center; }
.view-toggle button {
  background: var(--panel); border: 1px solid var(--stroke); color: var(--muted);
  padding: 7px 13px; border-radius: 9px; cursor: pointer; font-size: 13px; font-family: var(--font);
  transition: all 0.18s;
}
.view-toggle button:hover { color: var(--text); border-color: var(--stroke-strong); }
.view-toggle button.active { color: var(--bg); background: linear-gradient(135deg, var(--accent), var(--accent-2)); border-color: transparent; font-weight: 700; }
.view-toggle .export-btn { margin-left: 6px; color: var(--accent); }
.view-toggle .export-btn:hover { border-color: var(--accent); }
.view-toggle .ai-btn {
  margin-left: 6px; border: none; color: #04121a; font-weight: 700;
  background: linear-gradient(135deg, var(--accent-3), var(--accent-2));
  box-shadow: 0 0 18px rgba(177, 108, 255, 0.35);
}
.view-toggle .ai-btn:hover { filter: brightness(1.08); transform: translateY(-1px); }
.view-toggle .ai-btn:disabled { opacity: 0.6; cursor: progress; transform: none; }
.view-toggle .ai-btn.ai-off { background: var(--panel); color: var(--muted); box-shadow: none; border: 1px solid var(--stroke); }

/* AI synthesis panel */
.ai-panel {
  margin-bottom: 18px; border: 1px solid var(--stroke-strong); border-radius: var(--radius);
  background: linear-gradient(180deg, color-mix(in srgb, var(--accent-3) 8%, var(--panel)), var(--panel));
  backdrop-filter: blur(10px); overflow: hidden; animation: rise 0.35s ease both;
}
.ai-head { display: flex; align-items: center; justify-content: space-between; padding: 12px 18px; border-bottom: 1px solid var(--stroke); }
.ai-title { font-weight: 700; font-size: 15px; }
.ai-model { font-size: 11px; font-weight: 600; color: var(--accent-3); border: 1px solid rgba(177,108,255,0.4); padding: 2px 8px; border-radius: 999px; margin-left: 6px; }
.ai-close { background: none; border: 1px solid var(--stroke); color: var(--muted); width: 28px; height: 28px; border-radius: 8px; cursor: pointer; }
.ai-close:hover { color: var(--text); border-color: var(--stroke-strong); }
.ai-body { padding: 6px 20px 4px; font-size: 14.5px; line-height: 1.6; color: var(--text); }
.ai-body h3 { font-size: 15.5px; margin: 16px 0 6px; color: var(--accent); }
.ai-body h4 { font-size: 14px; margin: 12px 0 4px; color: var(--accent-2); }
.ai-body p { margin: 6px 0; color: var(--muted); }
.ai-body ul { margin: 6px 0 6px; padding-left: 20px; }
.ai-body li { margin: 4px 0; color: var(--muted); }
.ai-body strong { color: var(--text); }
.ai-body code { background: var(--bg-2); border: 1px solid var(--stroke); border-radius: 5px; padding: 1px 5px; font-size: 12.5px; }
.ai-cites { font-size: 11px; }
.ai-cite { color: var(--accent-3); text-decoration: none; font-weight: 700; padding: 0 1px; }
.ai-cite:hover { text-decoration: underline; }
.ai-foot { padding: 10px 20px 14px; font-size: 12px; color: var(--faint); border-top: 1px solid var(--stroke); margin-top: 6px; }
.ai-error { padding: 16px 4px; color: #ff8a8a; }
.ai-loading { padding: 16px 4px; color: var(--muted); display: flex; align-items: center; gap: 5px; }
.ai-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--accent-3); display: inline-block; animation: aipulse 1.2s infinite ease-in-out; }
.ai-dot:nth-child(2) { animation-delay: 0.2s; }
.ai-dot:nth-child(3) { animation-delay: 0.4s; margin-right: 6px; }
@keyframes aipulse { 0%, 100% { opacity: 0.3; transform: scale(0.8); } 50% { opacity: 1; transform: scale(1); } }
.ai-caret { display: inline-block; width: 8px; height: 15px; background: var(--accent-3); margin-left: 2px; vertical-align: text-bottom; animation: aiblink 1s steps(1) infinite; }
@keyframes aiblink { 50% { opacity: 0; } }

.results { display: flex; flex-direction: column; gap: 14px; }

/* Matrix view */
.matrix-view { animation: rise 0.35s ease both; }
.matrix-scroll { overflow-x: auto; border: 1px solid var(--stroke); border-radius: var(--radius); background: var(--panel); backdrop-filter: blur(10px); }
.matrix-table { width: 100%; border-collapse: collapse; font-size: 13.5px; min-width: 820px; }
.matrix-table thead th {
  position: sticky; top: 0; z-index: 2; text-align: left; padding: 12px 14px;
  background: var(--panel-solid); color: var(--muted); font-weight: 600; white-space: nowrap;
  border-bottom: 1px solid var(--stroke-strong);
}
.matrix-table th.sortable { cursor: pointer; user-select: none; }
.matrix-table th.sortable:hover { color: var(--accent); }
.matrix-table tbody tr { border-bottom: 1px solid var(--stroke); transition: background 0.15s; }
.matrix-table tbody tr:hover { background: rgba(120, 150, 220, 0.08); }
.matrix-table td { padding: 11px 14px; vertical-align: top; color: var(--text); }
.mx-idx { color: var(--faint); }
.mx-title { max-width: 380px; }
.mx-title a { color: var(--text); text-decoration: none; }
.mx-title a:hover { color: var(--accent); }
.mx-venue { max-width: 200px; color: var(--muted); font-style: italic; }
.mx-num { text-align: right; font-variant-numeric: tabular-nums; color: var(--accent-3); }
.mx-views { color: #46c8ff; }
.mx-oa { color: var(--accent); }
.mx-src { font-size: 11.5px; padding: 2px 8px; border-radius: 6px; white-space: nowrap; color: var(--sc); border: 1px solid color-mix(in srgb, var(--sc) 40%, transparent); background: color-mix(in srgb, var(--sc) 12%, transparent); }
.matrix-hint { text-align: center; color: var(--faint); font-size: 12.5px; margin: 14px 0 0; }

/* Map view */
.map-view { display: flex; flex-direction: column; gap: 18px; animation: rise 0.35s ease both; }
.map-panel { background: var(--panel); border: 1px solid var(--stroke); border-radius: var(--radius); padding: 18px 20px; backdrop-filter: blur(10px); }
.map-panel-head { display: flex; flex-direction: column; gap: 2px; margin-bottom: 12px; }
.map-panel-head h3 { margin: 0; font-size: 17px; }
.map-panel-sub { font-size: 12.5px; color: var(--faint); }
.map-legend { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 8px; }
.lg-item { display: inline-flex; align-items: center; gap: 6px; font-size: 12px; color: var(--muted); }
.lg-dot { width: 11px; height: 11px; border-radius: 50%; display: inline-block; }
.map-canvas-wrap { width: 100%; overflow-x: auto; }
.map-svg { width: 100%; min-width: 560px; height: auto; display: block; }
.map-axis { stroke: var(--stroke-strong); stroke-width: 1; }
.map-grid { stroke: var(--stroke); stroke-width: 1; stroke-dasharray: 3 4; }
.map-axis-lbl { fill: var(--faint); font-size: 11px; font-family: var(--font); }
.map-axis-title { fill: var(--muted); font-size: 12px; font-family: var(--font); font-weight: 600; }
.map-dot { cursor: pointer; fill-opacity: 0.72; stroke: rgba(255,255,255,0.35); stroke-width: 1; transition: fill-opacity 0.15s, stroke-width 0.15s; transform-origin: center; animation: pop 0.4s ease both; }
.map-dot:hover { fill-opacity: 0.95; stroke-width: 2.5; }
@keyframes pop { from { transform: scale(0); opacity: 0; } to { transform: scale(1); opacity: 1; } }

.theme-cloud { display: flex; flex-wrap: wrap; gap: 9px; align-items: center; }
.theme-chip {
  background: var(--bg-2); border: 1px solid var(--stroke); color: var(--text);
  padding: 6px 13px; border-radius: 999px; cursor: pointer; font-family: var(--font); line-height: 1.2;
  transition: all 0.18s;
}
.theme-chip:hover { border-color: var(--accent); color: var(--accent); transform: translateY(-2px); opacity: 1 !important; }
.card {
  background: var(--panel); border: 1px solid var(--stroke); border-radius: var(--radius);
  padding: 20px 22px; backdrop-filter: blur(10px);
  transition: border-color 0.2s, transform 0.2s;
  animation: rise 0.4s ease both;
}
@keyframes rise { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
.card:hover { border-color: var(--stroke-strong); transform: translateY(-2px); }
.card-top { display: flex; justify-content: space-between; gap: 12px; align-items: flex-start; }
.card h3 { margin: 0 0 8px; font-size: 17.5px; line-height: 1.35; }
.card h3 a { color: var(--text); text-decoration: none; }
.card h3 a:hover { color: var(--accent); }
.card-meta { font-size: 13px; color: var(--muted); margin-bottom: 10px; }
.card-authors { color: var(--faint); }
.card-abstract { font-size: 14px; color: var(--muted); margin: 10px 0 12px; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.card-tags { display: flex; flex-wrap: wrap; gap: 7px; align-items: center; }
.tag {
  font-size: 11.5px; padding: 3px 9px; border-radius: 6px;
  background: var(--bg-2); border: 1px solid var(--stroke); color: var(--muted);
}
.tag.src { color: var(--accent-2); border-color: var(--stroke-strong); }
.tag.oa { color: var(--accent); border-color: rgba(53,224,200,0.3); }
.tag.cite { color: var(--accent-3); }
.tag.hot { color: #ff8a3d; border-color: rgba(255, 138, 61, 0.4); background: rgba(255, 138, 61, 0.08); }
.tag.view { color: #46c8ff; border-color: rgba(70, 200, 255, 0.4); background: rgba(70, 200, 255, 0.08); }
.tag.src.id { color: #ff5a7a; border-color: rgba(255, 90, 122, 0.4); }
.src-card.id { border-color: rgba(255, 90, 122, 0.35); }
.src-card.id h3 { color: #ff5a7a; }
.card-actions { display: flex; gap: 8px; margin-top: 4px; }
.act-btn {
  font-size: 12.5px; padding: 6px 12px; border-radius: 8px; text-decoration: none;
  border: 1px solid var(--stroke); color: var(--text); transition: all 0.2s; cursor: pointer; background: none; font-family: var(--font);
}
.act-btn:hover { border-color: var(--accent); color: var(--accent); }
.act-btn.pdf { border-color: rgba(53,224,200,0.4); color: var(--accent); }

.pager { display: flex; justify-content: center; align-items: center; gap: 18px; margin: 28px 0 10px; }
.pg-btn {
  background: var(--panel); border: 1px solid var(--stroke); color: var(--text);
  padding: 10px 18px; border-radius: 10px; cursor: pointer; font-size: 14px; font-family: var(--font);
}
.pg-btn:hover:not(:disabled) { border-color: var(--stroke-strong); }
.pg-btn:disabled { opacity: 0.4; cursor: not-allowed; }
#pageInfo { color: var(--muted); font-size: 14px; }

/* States */
.loader { text-align: center; padding: 50px; }
.spinner {
  width: 40px; height: 40px; margin: 0 auto 16px; border-radius: 50%;
  border: 3px solid var(--stroke); border-top-color: var(--accent);
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
.empty { text-align: center; padding: 50px; color: var(--muted); }

/* Trending & sources */
.trending, .sources { max-width: 1080px; margin: 70px auto 0; padding: 0 24px; }
.trending h2, .sources h2 { font-size: 26px; margin: 0 0 6px; }
.section-sub { color: var(--muted); margin: 0 0 24px; }
.trending-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 16px; }
.t-card {
  background: var(--panel); border: 1px solid var(--stroke); border-radius: 14px; padding: 18px;
  transition: transform 0.2s, border-color 0.2s; animation: rise 0.4s ease both;
}
.t-card:hover { transform: translateY(-3px); border-color: var(--stroke-strong); }
.t-card h4 { margin: 0 0 8px; font-size: 15px; line-height: 1.4; }
.t-card h4 a { color: var(--text); text-decoration: none; }
.t-card h4 a:hover { color: var(--accent); }
.t-card .t-meta { font-size: 12.5px; color: var(--faint); margin-bottom: 8px; }
.t-card .t-cite { font-size: 12px; color: var(--accent-3); font-weight: 600; }
.skeleton { height: 150px; border-radius: 14px; background: linear-gradient(100deg, var(--panel) 30%, rgba(120,150,220,0.12) 50%, var(--panel) 70%); background-size: 200% 100%; animation: shimmer 1.4s infinite; }
@keyframes shimmer { to { background-position: -200% 0; } }

.source-cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 14px; }
.src-card { background: var(--panel); border: 1px solid var(--stroke); border-radius: 14px; padding: 18px; }
.src-card h3 { margin: 0 0 6px; font-size: 16px; color: var(--accent-2); }
.src-card p { margin: 0; font-size: 13.5px; color: var(--muted); }

footer { max-width: 900px; margin: 80px auto 40px; padding: 24px; text-align: center; color: var(--faint); font-size: 13px; border-top: 1px solid var(--stroke); }

@media (max-width: 640px) {
  .topbar { padding: 12px 16px; }
  .brand-sub { display: none; }
  .top-nav { gap: 14px; }
  .advanced { flex-direction: column; align-items: stretch; }
  .adv-field select, .adv-field input { min-width: 0; width: 100%; }
  .search-bar { flex-wrap: wrap; }
  .go-btn { width: 100%; }
}