:root {
  --bg-deep: #0c1f24;
  --bg-mid: #14343c;
  --bg-soft: #1a4550;
  --surface: rgba(232, 244, 242, 0.08);
  --surface-strong: rgba(232, 244, 242, 0.12);
  --ink: #e8f4f2;
  --ink-muted: #a8c5c0;
  --accent: #c6f54e;
  --accent-ink: #0c1f24;
  --line: rgba(232, 244, 242, 0.18);
  --focus: #7ee0d0;
  --danger-soft: #ffb4a8;
  --radius: 4px;
  --font-display: "Bebas Neue", "Arial Narrow", sans-serif;
  --font-body: "Source Sans 3", "Segoe UI", sans-serif;
  --space-xs: 0.35rem;
  --space-sm: 0.75rem;
  --space-md: 1.25rem;
  --space-lg: 2rem;
  --space-xl: 3.5rem;
  --max-width: 68rem;
  --transition: 180ms ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: 1.05rem;
  line-height: 1.55;
  color: var(--ink);
  background: var(--bg-deep);
  position: relative;
  overflow-x: hidden;
}

.atmosphere {
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(ellipse 80% 50% at 10% 0%, rgba(198, 245, 78, 0.12), transparent 55%),
    radial-gradient(ellipse 70% 60% at 90% 20%, rgba(30, 120, 130, 0.35), transparent 50%),
    linear-gradient(165deg, var(--bg-deep) 0%, var(--bg-mid) 45%, var(--bg-soft) 100%);
}

.atmosphere::after {
  content: "";
  position: absolute;
  inset: 0;
  opacity: 0.35;
  background-image:
    repeating-linear-gradient(
      -12deg,
      transparent,
      transparent 38px,
      rgba(232, 244, 242, 0.03) 38px,
      rgba(232, 244, 242, 0.03) 40px
    );
  pointer-events: none;
}

.page {
  width: min(100% - 2rem, var(--max-width));
  margin: 0 auto;
  padding: var(--space-xl) 0 var(--space-lg);
  display: grid;
  gap: var(--space-lg);
}

@media (min-width: 900px) {
  .page {
    gap: var(--space-lg) var(--space-xl);
    padding-block: 4rem 3rem;
  }

  .workspace {
    display: grid;
    grid-template-columns: 1.05fr 0.95fr;
    gap: var(--space-lg) var(--space-xl);
    align-items: start;
  }

  .advice {
    position: sticky;
    top: 1.5rem;
  }
}

.workspace {
  display: grid;
  gap: var(--space-lg);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.brand {
  animation: rise-in 520ms ease both;
}

.brand__name {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(4.5rem, 14vw, 7.5rem);
  letter-spacing: 0.04em;
  line-height: 0.9;
  color: var(--ink);
  text-transform: uppercase;
}

.brand__tagline {
  margin: var(--space-sm) 0 0;
  max-width: 34rem;
  color: var(--ink-muted);
  font-size: 1.1rem;
  font-weight: 500;
}

.calculator {
  animation: rise-in 560ms ease 80ms both;
}

.calculator.is-preset-applied {
  animation: preset-flash 420ms ease;
}

.fields {
  display: grid;
  gap: var(--space-md);
}

.field {
  margin: 0;
  padding: 0;
  border: 0;
  border-bottom: 1px solid var(--line);
  padding-bottom: var(--space-md);
}

.field__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
}

.field__header label,
.field__header legend {
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-muted);
  padding: 0;
}

.field__control {
  display: flex;
  align-items: baseline;
  gap: var(--space-sm);
}

.field__unit {
  color: var(--ink-muted);
  font-size: 0.95rem;
  white-space: nowrap;
}

input[type="number"] {
  width: 100%;
  max-width: 12rem;
  appearance: textfield;
  -moz-appearance: textfield;
  background: transparent;
  border: 0;
  border-bottom: 2px solid var(--line);
  border-radius: 0;
  padding: 0.35rem 0.15rem;
  font-family: var(--font-display);
  font-size: clamp(2rem, 6vw, 2.75rem);
  letter-spacing: 0.03em;
  color: var(--ink);
  transition: border-color var(--transition), color var(--transition);
}

input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

input[type="number"]:hover {
  border-color: rgba(198, 245, 78, 0.45);
}

input[type="number"]:focus {
  outline: none;
  border-color: var(--accent);
  color: var(--accent);
}

input[type="number"]:invalid {
  border-color: var(--danger-soft);
}

.time-inputs {
  display: flex;
  align-items: flex-end;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.time-part {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.time-part__label {
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-muted);
}

.time-part input {
  max-width: 4.5rem;
  text-align: center;
}

.time-sep {
  font-family: var(--font-display);
  font-size: 2rem;
  color: var(--ink-muted);
  padding-bottom: 0.35rem;
  line-height: 1;
}

.actions {
  margin-top: var(--space-lg);
}

.btn {
  font-family: var(--font-body);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background var(--transition), color var(--transition), transform var(--transition),
    border-color var(--transition);
}

.btn:active {
  transform: translateY(1px);
}

.btn--ghost {
  background: transparent;
  border: 1px solid transparent;
  color: var(--ink-muted);
  padding: 0.3rem 0.55rem;
}

.btn--ghost:hover,
.btn--ghost:focus-visible {
  color: var(--accent);
  border-color: rgba(198, 245, 78, 0.35);
  outline: none;
}

.btn--primary {
  background: var(--accent);
  color: var(--accent-ink);
  border: 0;
  padding: 0.85rem 1.5rem;
  font-size: 0.95rem;
}

.btn--primary:hover,
.btn--primary:focus-visible {
  filter: brightness(1.06);
  outline: 2px solid var(--focus);
  outline-offset: 3px;
}

.advice {
  padding-top: var(--space-sm);
  animation: rise-in 600ms ease 140ms both;
}

.advice__title {
  margin: 0 0 var(--space-md);
  font-family: var(--font-display);
  font-size: clamp(2rem, 5vw, 2.75rem);
  letter-spacing: 0.05em;
  font-weight: 400;
  text-transform: uppercase;
  color: var(--accent);
  border-bottom: 1px solid var(--line);
  padding-bottom: var(--space-sm);
}

.advice__body {
  display: grid;
  gap: var(--space-md);
}

.advice__body.is-updating {
  animation: advice-pulse 280ms ease;
}

.advice__body p,
.advice__goals {
  margin: 0;
  color: var(--ink);
}

.advice__subtitle {
  margin: 0;
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-muted);
}

.advice__goals {
  padding-left: 1.25rem;
  display: grid;
  gap: var(--space-sm);
}

.advice__goals li::marker {
  color: var(--accent);
  font-weight: 700;
}

.advice__tip {
  margin-top: var(--space-xs);
  padding-top: var(--space-md);
  border-top: 1px solid var(--line);
  color: var(--ink-muted);
  font-size: 0.98rem;
}

.advice__tip strong {
  color: var(--accent);
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-size: 0.8rem;
  display: block;
  margin-bottom: 0.35rem;
}

.presets {
  position: relative;
  z-index: 1;
  padding-top: var(--space-sm);
  border-top: 1px solid var(--line);
  animation: rise-in 640ms ease 180ms both;
}

.presets__intro {
  margin-bottom: var(--space-md);
}

.presets__title {
  margin: 0 0 var(--space-sm);
  font-family: var(--font-display);
  font-size: clamp(2rem, 5vw, 2.75rem);
  letter-spacing: 0.05em;
  font-weight: 400;
  text-transform: uppercase;
  color: var(--accent);
}

.presets__lede {
  margin: 0;
  max-width: 40rem;
  color: var(--ink-muted);
  font-size: 1rem;
}

.presets__scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border: 1px solid var(--line);
  background: var(--surface);
}

.presets__scroll:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 3px;
}

.presets__table {
  width: 100%;
  border-collapse: collapse;
  min-width: 36rem;
}

.presets__table th,
.presets__table td {
  padding: 0.85rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--line);
  vertical-align: middle;
}

.presets__table thead th {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-muted);
  background: var(--surface-strong);
  white-space: nowrap;
}

.presets__table tbody th {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 400;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink);
  white-space: nowrap;
}

.presets__distance {
  color: var(--ink-muted);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.presets__table tbody tr:last-child th,
.presets__table tbody tr:last-child td {
  border-bottom: 0;
}

.presets__table tbody tr:hover {
  background: rgba(198, 245, 78, 0.05);
}

.preset-time {
  font-family: var(--font-body);
  font-size: 0.98rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
  color: var(--ink);
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius);
  padding: 0.4rem 0.65rem;
  cursor: pointer;
  transition: background var(--transition), color var(--transition), border-color var(--transition);
  white-space: nowrap;
}

.preset-time:hover,
.preset-time:focus-visible {
  color: var(--accent);
  border-color: rgba(198, 245, 78, 0.4);
  background: rgba(198, 245, 78, 0.08);
  outline: none;
}

.preset-time.is-selected {
  color: var(--accent-ink);
  background: var(--accent);
  border-color: var(--accent);
}

.preset-time.is-selected:hover,
.preset-time.is-selected:focus-visible {
  color: var(--accent-ink);
  filter: brightness(1.06);
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

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

@keyframes advice-pulse {
  0% {
    opacity: 0.55;
    transform: translateY(4px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes preset-flash {
  0% {
    outline: 2px solid transparent;
    outline-offset: 6px;
  }
  35% {
    outline: 2px solid var(--accent);
    outline-offset: 6px;
  }
  100% {
    outline: 2px solid transparent;
    outline-offset: 10px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
}