:root {
  color-scheme: light;
  font-family: "Work Sans", "Segoe UI", sans-serif;
  color: #1f2933;
  --font-display: "Space Grotesk", "Work Sans", sans-serif;
  --bg-base: #f5f6ee;
  --bg-mid: #eef3e7;
  --bg-end: #f8faf2;
  --bg-accent: #e9f1de;
  --panel: #ffffff;
  --ink: #1f2933;
  --muted: #5b6776;
  --accent: #166f9d;
  --accent-strong: #95a95a;
  --shadow: 0 12px 24px rgba(15, 23, 42, 0.1);
  --curve-color: #166f9d;
  --curve-fill: rgba(22, 111, 157, 0.2);
  --plot-color: #95a95a;
  --hist-color: #c3d06d;
  --panel-border: rgba(15, 23, 42, 0.08);
  --input-border: rgba(15, 23, 42, 0.2);
  --hero-tip-border: rgba(22, 111, 157, 0.2);
  --hero-tip-ink: #344054;
  --accent-shadow: rgba(22, 111, 157, 0.18);
  --accent-shadow-strong: rgba(22, 111, 157, 0.3);
  --button-secondary-bg: #f1f5f9;
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    color: #e5e7eb;
    --bg-base: #0f172a;
    --bg-mid: #101c33;
    --bg-end: #0b1222;
    --bg-accent: #1f2a3d;
    --panel: #111827;
    --ink: #e5e7eb;
    --muted: #9ca3af;
    --accent: #4fb3e8;
    --accent-strong: #c8d97b;
    --shadow: 0 12px 24px rgba(0, 0, 0, 0.35);
    --curve-color: #4fb3e8;
    --curve-fill: rgba(79, 179, 232, 0.25);
    --plot-color: #c8d97b;
    --hist-color: #f5d36b;
    --panel-border: rgba(148, 163, 184, 0.18);
    --input-border: rgba(148, 163, 184, 0.35);
    --hero-tip-border: rgba(79, 179, 232, 0.35);
    --hero-tip-ink: #e2e8f0;
    --accent-shadow: rgba(79, 179, 232, 0.25);
    --accent-shadow-strong: rgba(79, 179, 232, 0.45);
    --button-secondary-bg: #1f2937;
  }
}

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

body {
  margin: 0;
  padding: 28px;
  min-height: 100vh;
  background: linear-gradient(
    120deg,
    var(--bg-base),
    var(--bg-mid) 55%,
    var(--bg-end) 100%
  );
  color: var(--ink);
}

.hero {
  display: flex;
  gap: 24px;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 28px;
}

.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 3vw, 2.8rem);
  margin: 0 0 8px;
  letter-spacing: -0.02em;
}

.hero p {
  margin: 0;
  color: var(--muted);
  font-size: 1rem;
}

h2 {
  font-family: var(--font-display);
  margin: 0 0 12px;
}

h3 {
  font-family: var(--font-display);
  margin: 0 0 10px;
  font-size: 1.1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 18px;
}

.brand-logo {
  width: clamp(110px, 18vw, 160px);
  height: auto;
  display: block;
}

.brand-name {
  color: var(--accent-strong);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.75rem;
  margin-bottom: 6px;
}

.hero-tip {
  max-width: 280px;
  padding: 12px 16px;
  border-radius: 12px;
  background: var(--bg-accent);
  border: 1px solid var(--hero-tip-border);
  color: var(--hero-tip-ink);
  font-size: 0.95rem;
}

main {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.panel {
  background: var(--panel);
  border-radius: 18px;
  padding: 18px;
  box-shadow: var(--shadow);
  border: 1px solid var(--panel-border);
  animation: floatIn 0.6s ease both;
}

.panel--wide {
  grid-column: 1 / -1;
}

.mode-switch {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.mode-button {
  background: var(--panel);
  color: var(--accent);
  border: 1px solid var(--input-border);
  box-shadow: none;
}

.mode-button:hover {
  box-shadow: 0 6px 16px var(--accent-shadow);
}

.mode-button.is-active {
  background: var(--accent);
  color: #ffffff;
  border-color: var(--accent);
}

.page {
  display: none;
}

.page.is-active {
  display: block;
}

.page-grid {
  display: grid;
  grid-template-columns: minmax(240px, 1fr) minmax(280px, 1.2fr);
  gap: 20px;
  align-items: start;
}

.page-inputs {
  display: grid;
  gap: 12px;
}

.page-chart {
  background: var(--panel);
  border-radius: 16px;
  padding: 16px;
  border: 1px solid var(--panel-border);
}

.helper {
  color: var(--muted);
  font-size: 0.95rem;
}

.input-stack {
  display: grid;
  gap: 10px;
}

label {
  font-size: 0.9rem;
  color: var(--muted);
}

input,
textarea {
  width: 100%;
  border-radius: 10px;
  border: 1px solid var(--input-border);
  padding: 10px 12px;
  font: inherit;
  background: var(--panel);
  color: var(--ink);
}

textarea {
  resize: vertical;
}

.field-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(90px, 1fr));
  gap: 10px;
}

button {
  border: none;
  border-radius: 999px;
  padding: 10px 18px;
  background: var(--accent);
  color: #ffffff;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

button:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 10px var(--accent-shadow-strong);
}

.button-secondary {
  background: var(--button-secondary-bg);
  color: var(--accent-strong);
}

.actions {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.actions-panel {
  padding: 14px 18px;
}

.status {
  color: var(--muted);
  font-size: 0.95rem;
}

canvas {
  width: 100%;
  height: 240px;
}

.page-chart canvas {
  height: 320px;
}

@keyframes floatIn {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 720px) {
  body {
    padding: 20px;
  }

  .hero {
    align-items: flex-start;
  }

  .brand {
    flex-direction: column;
    align-items: flex-start;
  }

  .hero-tip {
    max-width: none;
    width: 100%;
  }

  .page-grid {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  .panel {
    animation: none;
  }

  button {
    transition: none;
  }
}