:root {
  color-scheme: dark;
  --bg: #0b0d10;
  --panel: #13171c;
  --panel-2: #171c22;
  --border: #2a3038;
  --text: #f4f7fb;
  --muted: #929cab;
  --accent: #8ee3c0;
  --accent-strong: #4bd6a1;
  --blue: #7aa2ff;
  --danger: #ff8d8d;
  --shadow: 0 18px 45px rgba(0, 0, 0, 0.28);
}

* { box-sizing: border-box; }
html { min-width: 320px; background: var(--bg); }
body {
  margin: 0;
  min-width: 320px;
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background:
    radial-gradient(circle at 12% 0%, rgba(75, 214, 161, 0.09), transparent 28rem),
    radial-gradient(circle at 86% 10%, rgba(122, 162, 255, 0.08), transparent 30rem),
    var(--bg);
  color: var(--text);
}
button, input { font: inherit; }
button { -webkit-tap-highlight-color: transparent; }

.app-shell { width: min(1440px, calc(100% - 40px)); margin: 0 auto; padding: 48px 0 64px; }
.hero { display: flex; align-items: flex-end; justify-content: space-between; gap: 32px; margin-bottom: 30px; }
.hero > div:first-child { max-width: 760px; }
.eyebrow, .section-kicker { color: var(--accent); font-size: 0.72rem; font-weight: 700; letter-spacing: 0.16em; text-transform: uppercase; }
h1, h2, p { margin-top: 0; }
h1 { margin-bottom: 14px; font-size: clamp(2.2rem, 5vw, 4.5rem); line-height: 0.98; letter-spacing: -0.055em; }
h2 { margin: 4px 0 0; font-size: 1.08rem; letter-spacing: -0.025em; }
.hero-copy { margin-bottom: 0; max-width: 700px; color: var(--muted); line-height: 1.7; }
.formula-card { min-width: 330px; padding: 18px 20px; border: 1px solid var(--border); border-radius: 18px; background: rgba(19, 23, 28, 0.78); box-shadow: var(--shadow); }
.formula { display: block; font-family: "JetBrains Mono", monospace; font-size: 0.95rem; }
.formula-caption { display: block; margin-top: 7px; color: var(--muted); font-size: 0.76rem; }

.panel { border: 1px solid var(--border); border-radius: 22px; background: linear-gradient(180deg, rgba(23, 28, 34, 0.98), rgba(17, 21, 26, 0.98)); box-shadow: var(--shadow); }
.workspace { display: grid; grid-template-columns: minmax(0, 1fr) 320px; gap: 18px; }
.experiment-panel, .controls-panel, .chart-panel, .trial-panel, .explanation { padding: 22px; }
.panel-heading { display: flex; align-items: center; justify-content: space-between; gap: 16px; margin-bottom: 18px; }
.panel-heading.compact { margin-bottom: 22px; }

.ghost-button, .primary-button { min-height: 42px; padding: 0 15px; border-radius: 11px; cursor: pointer; transition: 160ms ease; }
.ghost-button { border: 1px solid var(--border); background: transparent; color: var(--text); }
.ghost-button:hover { border-color: #414a56; background: #1c2229; }
.primary-button { border: 1px solid var(--accent-strong); background: var(--accent-strong); color: #05251a; font-weight: 700; }
.primary-button:hover { transform: translateY(-1px); filter: brightness(1.06); }
.primary-button:disabled { cursor: not-allowed; opacity: 0.55; transform: none; }

.arena { position: relative; min-height: 460px; overflow: hidden; border: 1px solid #252c34; border-radius: 18px; background: #0d1115; }
.arena-grid { position: absolute; inset: 0; opacity: 0.34; background-image: linear-gradient(rgba(255,255,255,.035) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,.035) 1px, transparent 1px); background-size: 24px 24px; }
.start-target, .goal-target { position: absolute; z-index: 3; border-radius: 50%; transform: translate(-50%, -50%); cursor: pointer; touch-action: manipulation; }
.start-target { width: 72px; height: 72px; border: 1px solid #46505d; background: #1b222a; color: var(--text); font-size: 0.72rem; font-weight: 800; letter-spacing: 0.08em; }
.start-target:hover { border-color: var(--accent); color: var(--accent); }
.start-target[hidden] { display: none; }
.goal-target { border: 2px solid rgba(142, 227, 192, 0.8); background: radial-gradient(circle at 40% 35%, #b5f5dc, var(--accent-strong)); box-shadow: 0 0 0 10px rgba(75, 214, 161, 0.07), 0 8px 28px rgba(75, 214, 161, 0.22); }
.goal-target.ready { animation: targetPulse 1.8s ease-in-out infinite; }
@keyframes targetPulse { 50% { box-shadow: 0 0 0 18px rgba(75, 214, 161, 0.04), 0 8px 30px rgba(75, 214, 161, 0.28); } }
.distance-guide { position: absolute; z-index: 1; height: 1px; border-top: 1px dashed #687281; transform-origin: left center; pointer-events: none; }
.distance-guide::before, .distance-guide::after { content: ""; position: absolute; top: -4px; width: 7px; height: 7px; border-top: 1px solid #687281; border-right: 1px solid #687281; }
.distance-guide::before { left: 0; transform: rotate(-135deg); }
.distance-guide::after { right: 0; transform: rotate(45deg); }
.distance-guide span { position: absolute; left: 50%; top: -28px; transform: translateX(-50%); padding: 4px 8px; border: 1px solid #252c34; border-radius: 7px; background: #11161b; color: var(--muted); font-size: 0.7rem; white-space: nowrap; }
.arena-status { position: absolute; z-index: 2; bottom: 16px; left: 50%; transform: translateX(-50%); width: max-content; max-width: calc(100% - 32px); padding: 8px 12px; border: 1px solid #252c34; border-radius: 999px; background: rgba(13, 17, 21, 0.84); color: var(--muted); font-size: 0.78rem; text-align: center; backdrop-filter: blur(12px); }
.arena.flash-miss { animation: missFlash 220ms ease; }
@keyframes missFlash { 50% { box-shadow: inset 0 0 0 2px rgba(255, 141, 141, 0.75); } }

.experiment-actions { display: flex; align-items: center; justify-content: space-between; gap: 14px; margin-top: 16px; }
.mode-note { display: flex; align-items: center; gap: 8px; color: var(--muted); font-size: 0.8rem; }
.status-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--accent-strong); box-shadow: 0 0 0 4px rgba(75, 214, 161, 0.09); }

.control-group { padding: 18px 0; border-top: 1px solid var(--border); }
.control-label-row { display: flex; align-items: center; justify-content: space-between; gap: 14px; margin-bottom: 12px; }
.control-label-row label, .split-inputs label > span { font-size: 0.82rem; color: var(--muted); }
.control-label-row output { font-family: "JetBrains Mono", monospace; font-size: 0.8rem; }
input[type="range"] { width: 100%; accent-color: var(--accent-strong); }
.range-hints { display: flex; justify-content: space-between; margin-top: 5px; color: #697483; font-size: 0.68rem; }
.split-inputs { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.number-input-wrap { display: flex; align-items: center; gap: 6px; margin-top: 8px; padding: 0 10px; border: 1px solid var(--border); border-radius: 10px; background: #0f1317; }
.number-input-wrap input { width: 100%; min-width: 0; padding: 10px 0; border: 0; outline: 0; background: transparent; color: var(--text); }
.number-input-wrap span { color: var(--muted); font-size: 0.68rem; white-space: nowrap; }
.difficulty-card { margin-top: 12px; padding: 16px; border: 1px solid var(--border); border-radius: 15px; background: #10151a; }
.difficulty-card > div:first-child { display: flex; justify-content: space-between; gap: 14px; font-size: 0.78rem; color: var(--muted); }
.difficulty-card strong { color: var(--text); }
.difficulty-meter { height: 6px; margin: 12px 0 10px; overflow: hidden; border-radius: 999px; background: #252c33; }
.difficulty-meter span { display: block; height: 100%; border-radius: inherit; background: linear-gradient(90deg, var(--accent), var(--blue)); transition: width 180ms ease; }
.difficulty-card p { margin: 0; color: var(--muted); font-size: 0.73rem; }

.metrics-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin: 18px 0; }
.metric-card { padding: 18px; border: 1px solid var(--border); border-radius: 17px; background: var(--panel); }
.metric-card span { display: block; color: var(--muted); font-size: 0.73rem; }
.metric-card strong { display: block; margin: 9px 0 6px; font-size: clamp(1.45rem, 3vw, 2.15rem); letter-spacing: -0.04em; }
.metric-card small { color: #6f7a88; font-size: 0.7rem; }

.lower-grid { display: grid; grid-template-columns: minmax(0, 1.35fr) minmax(360px, .65fr); gap: 18px; }
.legend { display: flex; align-items: center; gap: 7px; color: var(--muted); font-size: 0.7rem; }
.legend i { width: 18px; height: 3px; border-radius: 999px; }
.legend-measured { margin-left: 4px; background: var(--accent); }
.legend-predicted { margin-left: 8px; background: var(--blue); }
.chart-wrap { position: relative; min-height: 290px; }
#resultsChart { display: block; width: 100%; height: 290px; }
.empty-chart { position: absolute; inset: 0; display: grid; place-items: center; color: var(--muted); font-size: 0.8rem; pointer-events: none; }
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 0.76rem; }
th { padding: 10px 8px; border-bottom: 1px solid var(--border); color: var(--muted); font-weight: 600; text-align: left; }
td { padding: 12px 8px; border-bottom: 1px solid rgba(42, 48, 56, 0.6); white-space: nowrap; }
.empty-row td { padding: 46px 8px; color: var(--muted); text-align: center; }
.explanation { margin-top: 18px; display: grid; grid-template-columns: 220px 1fr; gap: 38px; }
.explanation-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.explanation-grid p { margin: 0; color: var(--muted); font-size: 0.82rem; line-height: 1.65; }
.explanation-grid strong { color: var(--text); }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { scroll-behavior: auto !important; animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; } }
@media (max-width: 980px) {
  .hero { align-items: flex-start; flex-direction: column; }
  .formula-card { min-width: 0; width: 100%; }
  .workspace, .lower-grid { grid-template-columns: 1fr; }
  .metrics-grid { grid-template-columns: repeat(2, 1fr); }
  .controls-panel { order: -1; }
  .explanation { grid-template-columns: 1fr; gap: 20px; }
}
@media (max-width: 680px) {
  .app-shell { width: min(100% - 24px, 1440px); padding: 28px 0 42px; }
  .experiment-panel, .controls-panel, .chart-panel, .trial-panel, .explanation { padding: 16px; }
  .arena { min-height: 390px; }
  .metrics-grid { grid-template-columns: 1fr 1fr; gap: 10px; }
  .metric-card { padding: 14px; }
  .experiment-actions { align-items: stretch; flex-direction: column; }
  .primary-button { width: 100%; }
  .explanation-grid { grid-template-columns: 1fr; }
  .legend { width: 100%; }
}
@media (max-width: 430px) {
  .metrics-grid { grid-template-columns: 1fr; }
  .panel-heading { align-items: flex-start; flex-direction: column; }
  .ghost-button { width: 100%; }
  .split-inputs { grid-template-columns: 1fr; }
}