:root {
  color-scheme: light;
  --bg: #f5f2ec;
  --panel: #ffffff;
  --ink: #17212b;
  --muted: #61707f;
  --line: #cad3dd;
  --accent: #007976;
  --accent-strong: #005f5d;
  --disabled: #9aa4ae;
  --shadow: 0 24px 60px rgba(31, 45, 61, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  min-height: 100vh;
  margin: 0;
  display: grid;
  place-items: center;
  background:
    linear-gradient(135deg, rgba(0, 121, 118, 0.14), transparent 36%),
    linear-gradient(315deg, rgba(198, 78, 53, 0.12), transparent 34%),
    var(--bg);
  color: var(--ink);
  font-family: "Segoe UI", Arial, sans-serif;
}

button,
input {
  font: inherit;
}

.app-shell {
  width: min(960px, calc(100vw - 32px));
  padding: 32px 0;
}

.tester {
  display: grid;
  gap: 28px;
  padding: clamp(24px, 5vw, 48px);
  background: var(--panel);
  border: 1px solid rgba(23, 33, 43, 0.08);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.heading {
  display: grid;
  gap: 6px;
}

.eyebrow {
  margin: 0;
  color: var(--accent-strong);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(2.25rem, 8vw, 4.75rem);
  line-height: 0.95;
  letter-spacing: 0;
}

.controls {
  display: grid;
  gap: 18px;
}

.field,
.slider-field {
  display: grid;
  gap: 2px;
}

.field > span:first-child {
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 650;
}

.number-scroll {
  display: block;
  max-width: 100%;
  overflow-x: auto;
  padding-bottom: 4px;
}

input[type="text"] {
  width: 100%;
  height: 44px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fbfcfd;
  color: var(--ink);
  outline: none;
}

#numberInput {
  width: 100%;
  min-width: 50ch;
}

input[readonly] {
  background: #edf2f6;
  color: #344453;
}

#iterationsOutput,
#currentIterationOutput {
  width: 4.5ch;
  min-width: 4.5ch;
  padding: 0 2px;
  text-align: center;
}

#resultOutput {
  width: 18ch;
  text-align: center;
}

input[type="text"]:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(0, 121, 118, 0.18);
}

.iteration-row {
  display: grid;
  grid-template-columns: 126px minmax(220px, 1fr);
  gap: 18px;
  align-items: end;
}

input[type="range"] {
  width: 100%;
  height: 24px;
  accent-color: var(--accent);
}

.slider-ticks {
  position: relative;
  display: block;
  width: 100%;
  height: 24px;
  margin-top: -2px;
  padding: 0 7px;
}

.slider-ticks span {
  position: absolute;
  left: var(--tick-left);
  top: 0;
  display: grid;
  justify-items: center;
  gap: 3px;
  min-width: 2ch;
  color: var(--muted);
  font-size: 0.78rem;
  line-height: 1;
  transform: translateX(-50%);
}

.slider-ticks span::before {
  content: "";
  width: 1px;
  height: 8px;
  background: #6e7b86;
}

.slider-ticks span.minor::before {
  height: 5px;
}

.actions {
  padding-top: 18px;
}

button {
  min-width: 128px;
  height: 44px;
  border: 0;
  border-radius: 6px;
  background: var(--accent);
  color: #ffffff;
  font-weight: 700;
  cursor: pointer;
}

button:hover:not(:disabled) {
  background: var(--accent-strong);
}

button:disabled {
  background: var(--disabled);
  cursor: not-allowed;
}

@media (max-width: 640px) {
  body {
    place-items: start center;
  }

  .iteration-row {
    grid-template-columns: 1fr;
  }

  .tester {
    padding: 24px 18px;
  }
}