:root {
  --bg: #fafaf7;
  --surface: #ffffff;
  --ink: #18261d;
  --ink-soft: #54655c;
  --muted: #97a39c;
  --line: #e6e8e3;

  --green: #2f8f3f;
  --green-strong: #1f7530;
  --green-soft: #c8e6c9;
  --green-bg: #ecf6ec;

  --red: #c94434;
  --red-bg: #fbeae6;

  --gray: #6b7280;

  --shadow-sm: 0 1px 2px rgba(20, 30, 25, 0.04), 0 1px 1px rgba(20, 30, 25, 0.03);
  --shadow-md: 0 8px 24px rgba(20, 30, 25, 0.06), 0 2px 6px rgba(20, 30, 25, 0.04);
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Inter", "SF Pro Text", -apple-system, BlinkMacSystemFont, "Helvetica Neue", Arial, sans-serif;
  font-size: 15px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

.page {
  max-width: 1240px;
  margin: 0 auto;
  padding: 56px 28px 64px;
}

/* HERO */
.hero {
  text-align: center;
  margin-bottom: 36px;
}
.badge {
  display: inline-block;
  padding: 6px 12px;
  background: var(--green-bg);
  color: var(--green-strong);
  border: 1px solid var(--green-soft);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 18px;
}
h1 {
  font-size: clamp(28px, 4vw, 44px);
  font-weight: 700;
  letter-spacing: -0.015em;
  margin: 0 0 12px;
}
h1 .brand {
  background: linear-gradient(135deg, var(--green-strong), var(--green));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.subtitle {
  margin: 0 auto;
  max-width: 640px;
  color: var(--ink-soft);
  font-size: 16px;
}

/* RESET BUTTON */
.reset-btn {
  margin-left: 4px;
  padding: 4px 12px;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink-soft);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  font-family: inherit;
  transition: all 0.15s ease;
}
.reset-btn:hover {
  border-color: var(--green);
  color: var(--green-strong);
  background: var(--green-bg);
}

/* CHARTS */
.charts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(440px, 1fr));
  gap: 20px;
  margin-bottom: 36px;
}
.chart-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 22px 22px 18px;
  box-shadow: var(--shadow-md);
}
.chart-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 8px;
  flex-wrap: wrap;
  gap: 8px;
}
.chart-header h2 {
  margin: 0;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.005em;
}
.chart-header .symbol {
  color: var(--ink-soft);
  font-weight: 500;
  font-size: 14px;
  margin-left: 2px;
  font-style: italic;
}
.legend {
  display: flex;
  gap: 14px;
  font-size: 12px;
  color: var(--ink-soft);
}
.legend-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  display: inline-block;
}
.dot-green { background: var(--green); }
.dot-red { background: var(--red); }
.dot-gray { background: var(--gray); }
.dash {
  width: 16px;
  height: 0;
  display: inline-block;
}
.dash-green { border-top: 2px dashed var(--green); }
.dash-gray { border-top: 2px dashed var(--gray); }

svg {
  width: 100%;
  height: auto;
  display: block;
  user-select: none;
  cursor: default;
}

.hint {
  margin: 6px 4px 0;
  font-size: 12px;
  color: var(--muted);
  text-align: center;
}

/* CHART INTERNALS */
.axis line, .axis path {
  stroke: var(--line);
  stroke-width: 1;
  shape-rendering: crispEdges;
}
.axis text {
  fill: var(--ink-soft);
  font-size: 11px;
  font-family: inherit;
}
.axis-label {
  fill: var(--ink-soft);
  font-size: 12px;
  font-weight: 500;
}
.grid line {
  stroke: var(--line);
  stroke-dasharray: 3 4;
  stroke-width: 1;
}
.bound {
  stroke: var(--green);
  stroke-width: 1.5;
  stroke-dasharray: 6 5;
  opacity: 0.55;
  fill: none;
}
.entropy-line {
  fill: none;
  stroke: var(--green-strong);
  stroke-width: 2.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.entropy-area {
  fill: var(--green);
  opacity: 0.08;
}
.entropy-baseline {
  fill: none;
  stroke: var(--gray);
  stroke-width: 2;
  stroke-dasharray: 4 5;
  stroke-linecap: round;
  opacity: 0.7;
}
.acc-line {
  fill: none;
  stroke: var(--red);
  stroke-width: 2.4;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.acc-baseline {
  fill: none;
  stroke: var(--gray);
  stroke-width: 2;
  stroke-dasharray: 4 5;
  stroke-linecap: round;
  opacity: 0.7;
}
.handle {
  fill: var(--green-strong);
  stroke: #fff;
  stroke-width: 2.5;
  cursor: grab;
  transition: r 0.12s ease, fill 0.12s ease;
}
.handle:hover {
  fill: var(--green);
  r: 8;
}
.handle.dragging {
  cursor: grabbing;
  fill: var(--green);
  r: 9;
}
.bg-band-good {
  fill: #e8f5e9;
  opacity: 0.55;
}
.bg-band-bad {
  fill: #fdecea;
  opacity: 0.45;
}

/* INSIGHT CARDS */
.insight {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
  margin-bottom: 28px;
}
.insight-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 18px 18px 16px;
  box-shadow: var(--shadow-sm);
}
.insight-card.highlight {
  background: var(--green-bg);
  border-color: var(--green-soft);
}
.insight-icon {
  font-size: 20px;
  color: var(--green-strong);
  margin-bottom: 6px;
  font-weight: 700;
}
.insight-card h3 {
  margin: 0 0 6px;
  font-size: 15px;
  font-weight: 600;
}
.insight-card p {
  margin: 0;
  font-size: 13px;
  color: var(--ink-soft);
  line-height: 1.5;
}

/* FOOTER */
.footer {
  text-align: center;
  font-size: 12px;
  color: var(--muted);
  padding-top: 8px;
}

@media (max-width: 720px) {
  .page { padding: 36px 16px 48px; }
  .chart-card { padding: 16px 14px; }
  .legend { width: 100%; }
}