/* Tip & Bill Splitter — clean, mobile-first */

:root {
  --bg: #f4f7f6;
  --surface: #ffffff;
  --text: #1a2e2b;
  --muted: #5a6f6b;
  --border: #d8e3e0;
  --accent: #0f766e;
  --accent-hover: #0d9488;
  --accent-soft: #ccfbf1;
  --highlight: #134e4a;
  --radius: 12px;
  --shadow: 0 4px 24px rgba(15, 118, 110, 0.08);
  --font: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

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

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100dvh;
  font-family: var(--font);
  font-size: 1rem;
  line-height: 1.5;
  color: var(--text);
  background: var(--bg);
}

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

.page {
  max-width: 440px;
  margin: 0 auto;
  padding: 1.25rem 1rem 2.5rem;
}

.header {
  text-align: center;
  margin-bottom: 1.25rem;
}

.header h1 {
  margin: 0 0 0.35rem;
  font-size: clamp(1.4rem, 5vw, 1.75rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--highlight);
}

.tagline {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.card {
  background: var(--surface);
  border-radius: calc(var(--radius) + 4px);
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  padding: 1.25rem 1.15rem 1.35rem;
}

.field {
  margin-bottom: 1.15rem;
}

.field label,
.field legend {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 0.4rem;
  color: var(--text);
}

.tip-field {
  border: 0;
  padding: 0;
  margin: 0 0 1.15rem;
  min-width: 0;
}

.tip-field legend {
  padding: 0;
}

.optional {
  font-weight: 400;
  color: var(--muted);
}

.hint {
  margin: 0.35rem 0 0;
  font-size: 0.8rem;
  color: var(--muted);
}

.input-affix {
  display: flex;
  align-items: stretch;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #fafcfb;
  overflow: hidden;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.input-affix:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(15, 118, 110, 0.18);
  background: #fff;
}

.input-affix .prefix,
.input-affix .suffix-label {
  display: flex;
  align-items: center;
  padding: 0 0.75rem;
  color: var(--muted);
  font-weight: 600;
  background: #eef5f3;
  user-select: none;
}

.input-affix input {
  flex: 1;
  border: 0;
  background: transparent;
  padding: 0.7rem 0.75rem;
  font-size: 1.1rem;
  font-family: inherit;
  color: var(--text);
  min-width: 0;
  width: 100%;
}

.input-affix input:focus {
  outline: none;
}

.input-affix.suffix .suffix-label {
  border-left: 1px solid var(--border);
}

/* Hide number spinners — use our steppers / presets instead */
input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

input[type="number"] {
  -moz-appearance: textfield;
  appearance: textfield;
}

.tip-presets {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.5rem;
  margin-bottom: 0.65rem;
}

.tip-btn {
  font-family: inherit;
  font-size: 0.95rem;
  font-weight: 600;
  padding: 0.65rem 0.25rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: #fafcfb;
  color: var(--text);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
}

.tip-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.tip-btn[aria-pressed="true"] {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.tip-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.custom-tip-row {
  max-width: 8.5rem;
}

.stepper {
  display: flex;
  align-items: stretch;
  gap: 0.5rem;
}

.stepper input {
  flex: 1;
  text-align: center;
  font-size: 1.15rem;
  font-weight: 600;
  font-family: inherit;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.65rem;
  background: #fafcfb;
  color: var(--text);
  min-width: 0;
}

.stepper input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(15, 118, 110, 0.18);
  background: #fff;
}

.stepper-btn {
  width: 2.75rem;
  flex-shrink: 0;
  font-size: 1.35rem;
  font-weight: 600;
  line-height: 1;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #eef5f3;
  color: var(--highlight);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}

.stepper-btn:hover {
  background: var(--accent-soft);
  border-color: var(--accent);
}

.stepper-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.actions {
  margin-top: 0.25rem;
  margin-bottom: 0.25rem;
}

.btn-secondary {
  font-family: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  padding: 0.55rem 1rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
}

.btn-secondary:hover {
  color: var(--text);
  border-color: var(--muted);
  background: #f0f4f3;
}

.btn-secondary:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.results {
  margin-top: 1.35rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--border);
}

.results-heading {
  margin: 0 0 0.75rem;
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted);
}

.results-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin: 0;
}

.result-item {
  margin: 0;
  padding: 0.85rem 0.9rem;
  background: #f7faf9;
  border-radius: 10px;
  border: 1px solid var(--border);
}

.result-item dt {
  margin: 0 0 0.2rem;
  font-size: 0.8rem;
  color: var(--muted);
  font-weight: 500;
}

.result-item dd {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--text);
}

.result-item.highlight {
  grid-column: 1 / -1;
  background: var(--accent-soft);
  border-color: #99f6e4;
}

.result-item.highlight dd {
  font-size: 1.6rem;
  color: var(--highlight);
}

.summary {
  margin: 0.85rem 0 0;
  font-size: 0.85rem;
  color: var(--muted);
  text-align: center;
}

.footer {
  margin-top: 1.5rem;
  text-align: center;
}

.footer p {
  margin: 0;
  font-size: 0.8rem;
  color: var(--muted);
}

@media (min-width: 480px) {
  .page {
    padding-top: 2rem;
  }

  .card {
    padding: 1.5rem 1.4rem 1.6rem;
  }
}