@import url('https://fonts.googleapis.com/css2?family=IBM+Plex+Mono:wght@400;500;600;700&family=IBM+Plex+Sans:wght@400;500;600&display=swap');

:root{
  --bg: #0e1013;
  --panel: #161920;
  --panel-2: #1c2029;
  --border: #262b36;
  --text: #e7e9ee;
  --text-dim: #8b93a3;
  --text-dimmer: #5b6272;
  --accent: #f2a65a;
  --accent-dim: #b97f42;
  --accent-glow: rgba(242,166,90,0.18);
  --code-kw: #7fd4c9;
  --code-str: #e0b869;
  --code-com: #626a7a;
  --code-fn: #9fc4ee;
  --radius: 10px;
  --mono: 'IBM Plex Mono', ui-monospace, Menlo, Consolas, monospace;
  --sans: 'IBM Plex Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

*{ box-sizing: border-box; }
html{ scroll-behavior: smooth; }

body{
  margin:0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  line-height: 1.55;
  min-height:100vh;
  position: relative;
}

/* subtle scanline texture, static, no animation */
.scanlines{
  position: fixed; inset:0; pointer-events:none; z-index:0;
  background: repeating-linear-gradient(
    to bottom, rgba(255,255,255,0.012) 0px, rgba(255,255,255,0.012) 1px,
    transparent 1px, transparent 3px
  );
  opacity: 0.5;
}

/* ---------- topbar ---------- */
.topbar{
  position: sticky; top:0; z-index:10;
  display:flex; align-items:center; justify-content:space-between;
  padding: 14px 22px;
  background: rgba(14,16,19,0.88);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.brand{ display:flex; align-items:center; gap:10px; font-family: var(--mono); }
.brand-glyph{ color: var(--accent); font-weight:700; font-size: 18px; }
.brand-text{ font-weight:600; font-size:17px; letter-spacing: 0.2px; }
.brand-dim{ color: var(--text-dim); font-weight: 400; }
.stats{ font-family: var(--mono); font-size:12px; color: var(--text-dimmer); }

/* ---------- layout ---------- */
.wrap{
  max-width: 880px;
  margin: 0 auto;
  padding: 40px 20px 100px;
  position: relative; z-index:1;
}

.hero{ margin-bottom: 28px; }
.hero h1{
  font-family: var(--mono);
  font-size: clamp(26px, 5vw, 38px);
  font-weight: 700;
  margin: 0 0 10px;
  letter-spacing: -0.5px;
}
.cursor-line{ color: var(--accent); }
.cursor-line::after{
  content: "_";
  animation: blink 1s step-end infinite;
  color: var(--accent);
  margin-left: 2px;
}
@keyframes blink{ 50%{ opacity: 0; } }
.sub{ color: var(--text-dim); font-size: 15px; max-width: 56ch; margin:0; }

/* ---------- search ---------- */
.search-box{
  display:flex; align-items:center; gap:10px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 18px;
  margin: 24px 0 16px;
  transition: border-color .15s ease, box-shadow .15s ease;
}
.search-box:focus-within{
  border-color: var(--accent-dim);
  box-shadow: 0 0 0 3px var(--accent-glow);
}
.search-icon{ font-family: var(--mono); color: var(--accent); font-weight:700; font-size:16px; }
#search{
  flex:1; background: transparent; border: none; outline: none;
  color: var(--text); font-family: var(--mono); font-size: 15px;
}
#search::placeholder{ color: var(--text-dimmer); }
.search-count{ font-family: var(--mono); font-size: 12px; color: var(--text-dimmer); white-space: nowrap; }

/* ---------- tabs ---------- */
.tabs{ display:flex; gap:8px; margin-bottom: 24px; }
.tab{
  font-family: var(--mono); font-size: 13px;
  background: transparent; color: var(--text-dim);
  border: 1px solid var(--border); border-radius: 999px;
  padding: 7px 16px; cursor:pointer;
  transition: all .15s ease;
}
.tab:hover{ color: var(--text); border-color: var(--text-dimmer); }
.tab.active{ background: var(--accent-glow); border-color: var(--accent-dim); color: var(--accent); }

/* ---------- results ---------- */
.results{ display:flex; flex-direction:column; gap: 10px; }

.group-heading{
  font-family: var(--mono); font-size: 12px; font-weight:600;
  text-transform: uppercase; letter-spacing: 1px;
  color: var(--accent); margin: 26px 0 10px; padding-bottom:6px;
  border-bottom: 1px solid var(--border);
}
.group-heading:first-child{ margin-top: 0; }

.card{
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
}
.card + .card{ margin-top: 0; }

.card-q{
  font-weight: 600; font-size: 15px; margin: 0 0 8px;
  display:flex; gap: 10px; align-items:flex-start;
}
.q-idx{ color: var(--accent); font-family: var(--mono); font-size: 13px; flex-shrink:0; margin-top:2px; }
.card-a{ color: var(--text-dim); font-size: 14.5px; margin:0; }

mark{ background: var(--accent-glow); color: var(--accent); border-radius: 3px; padding: 0 2px; }

/* practice card */
.card.practice .card-q{ margin-bottom: 4px; }
.card-note{ color: var(--text-dimmer); font-size: 13px; font-style: italic; margin: 0 0 10px; }
.code-wrap{ position: relative; margin-top: 8px; }
pre.code{
  margin:0; padding: 14px 16px; background: var(--panel-2);
  border: 1px solid var(--border); border-radius: 8px;
  overflow-x: auto; font-family: var(--mono); font-size: 13px; line-height: 1.6;
}
.copy-btn{
  position: absolute; top: 8px; right: 8px;
  font-family: var(--mono); font-size: 11px;
  background: var(--panel); color: var(--text-dim);
  border: 1px solid var(--border); border-radius: 6px;
  padding: 4px 10px; cursor: pointer;
  transition: all .15s ease;
}
.copy-btn:hover{ color: var(--accent); border-color: var(--accent-dim); }
.copy-btn.copied{ color: var(--accent); border-color: var(--accent-dim); }

.explain-btn{
  display:block; margin-top:10px;
  font-family: var(--mono); font-size: 12px;
  background: transparent; color: var(--text-dim);
  border: 1px dashed var(--border); border-radius: 6px;
  padding: 6px 12px; cursor: pointer; text-align:left;
  transition: all .15s ease;
}
.explain-btn:hover{ color: var(--accent); border-color: var(--accent-dim); }
.explain-btn.open{ color: var(--accent); border-color: var(--accent-dim); border-style: solid; }
.explain-panel{
  margin-top: 8px; padding: 4px 4px;
  background: var(--accent-glow); border: 1px solid var(--accent-dim);
  border-radius: 8px;
  flex-direction: column; gap: 2px;
}
.explain-panel:not([hidden]){ display: flex; }
.explain-panel[hidden]{ display: none; }
.explain-row{
  display:flex; align-items: flex-start; gap: 10px;
  padding: 8px 10px; border-radius: 6px;
  transition: background .1s ease;
}
.explain-row:hover{ background: rgba(255,255,255,0.03); }
.explain-code{
  flex: 0 0 auto; max-width: 42%;
  font-family: var(--mono); font-size: 12px; color: var(--accent);
  background: rgba(0,0,0,0.25); border-radius: 5px; padding: 3px 7px;
  white-space: pre-wrap; word-break: break-word; line-height: 1.5;
}
.explain-arrow{ color: var(--text-dimmer); flex: 0 0 auto; margin-top: 3px; font-size: 12px; }
.explain-desc{ color: var(--text); font-size: 13.5px; line-height: 1.55; flex: 1 1 auto; }

@media (max-width: 600px){
  .explain-row{ flex-direction: column; gap: 4px; }
  .explain-code{ max-width: 100%; }
  .explain-arrow{ display:none; }
}

.tok-kw{ color: var(--code-kw); }
.tok-str{ color: var(--code-str); }
.tok-com{ color: var(--code-com); }
.tok-fn{ color: var(--code-fn); }

.empty-state{
  text-align:center; color: var(--text-dimmer);
  font-family: var(--mono); font-size: 14px; margin-top: 60px;
}

/* ---------- footer ---------- */
.foot{
  position: fixed; bottom:0; left:0; right:0; z-index:5;
  display:flex; justify-content:center; gap:10px;
  font-family: var(--mono); font-size: 11px; color: var(--text-dimmer);
  padding: 10px; background: rgba(14,16,19,0.9); backdrop-filter: blur(6px);
  border-top: 1px solid var(--border);
}
.foot-dot{ color: var(--text-dimmer); }

/* ---------- focus visibility ---------- */
a:focus-visible, button:focus-visible, input:focus-visible{
  outline: 2px solid var(--accent); outline-offset: 2px;
}

/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion: reduce){
  .cursor-line::after{ animation: none; opacity: 1; }
  html{ scroll-behavior: auto; }
}

/* ---------- mobile ---------- */
@media (max-width: 600px){
  .wrap{ padding: 24px 14px 90px; }
  .topbar{ padding: 12px 14px; }
  .search-box{ padding: 12px 14px; }
  .card{ padding: 14px; }
  .foot{ font-size: 10px; gap:6px; flex-wrap: wrap; }
}