/* ==========================================================================
   Split the Bill — styles
   A small, framework-free stylesheet. Tokens first, then layout, then
   components. Light & dark themes via prefers-color-scheme.
   ========================================================================== */

:root {
  color-scheme: light dark;

  /* Palette — light */
  --color-bg: #f6f7fb;
  --color-surface: #ffffff;
  --color-text: #1e293b;
  --color-muted: #64748b;
  --color-accent: #2563eb;
  --color-accent-text: #ffffff;
  --color-border: #e2e8f0;
  --color-credit: #047857;
  --color-credit-bg: #ecfdf5;
  --color-debit: #b45309;
  --color-debit-bg: #fffbeb;
  --color-danger: #dc2626;

  /* Shape & depth */
  --radius: 14px;
  --radius-sm: 10px;
  --shadow: 0 10px 30px -12px rgba(15, 23, 42, 0.25);
  --shadow-sm: 0 2px 8px -4px rgba(15, 23, 42, 0.3);

  --max-width: 40rem;
  --font: "Segoe UI", system-ui, -apple-system, Roboto, Helvetica, Arial,
    sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0b1120;
    --color-surface: #131c2e;
    --color-text: #e2e8f0;
    --color-muted: #94a3b8;
    --color-accent: #60a5fa;
    --color-accent-text: #0b1120;
    --color-border: #233047;
    --color-credit: #34d399;
    --color-credit-bg: #0c2a22;
    --color-debit: #fbbf24;
    --color-debit-bg: #2a230c;
    --color-danger: #f87171;
    --shadow: 0 12px 32px -12px rgba(0, 0, 0, 0.6);
    --shadow-sm: 0 2px 10px -4px rgba(0, 0, 0, 0.6);
  }
}

/* --------------------------------------------------------------------------
   Base
   -------------------------------------------------------------------------- */

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  font-family: var(--font);
  line-height: 1.5;
  color: var(--color-text);
  background: var(--color-bg);
  /* A soft gradient wash that works in both themes. */
  background-image: radial-gradient(
      1200px 600px at 100% -10%,
      color-mix(in srgb, var(--color-accent) 12%, transparent),
      transparent
    ),
    radial-gradient(
      900px 500px at -10% 110%,
      color-mix(in srgb, var(--color-accent) 8%, transparent),
      transparent
    );
  background-attachment: fixed;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--color-accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

h1,
h2,
p {
  margin: 0;
}

:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--color-accent) 60%, transparent);
  outline-offset: 2px;
  border-radius: 4px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--color-accent);
  color: var(--color-accent-text);
  padding: 0.5rem 1rem;
  border-radius: 0 0 var(--radius-sm) 0;
  z-index: 10;
}
.skip-link:focus {
  left: 0;
}

/* --------------------------------------------------------------------------
   Header & footer
   -------------------------------------------------------------------------- */

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  max-width: var(--max-width);
  width: 100%;
  margin: 0 auto;
  padding: 1.25rem 1.25rem 0.5rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  color: var(--color-text);
}
.brand:hover {
  text-decoration: none;
}
.brand-mark {
  font-size: 1.4rem;
}

.site-nav a {
  font-weight: 600;
}

.site-footer {
  max-width: var(--max-width);
  width: 100%;
  margin: 2rem auto 0;
  padding: 1.5rem 1.25rem 2.5rem;
  color: var(--color-muted);
  font-size: 0.85rem;
  text-align: center;
}

/* --------------------------------------------------------------------------
   App shell
   -------------------------------------------------------------------------- */

.app {
  max-width: var(--max-width);
  width: 100%;
  margin: 0 auto;
  padding: 0.5rem 1.25rem 1rem;
  flex: 1 0 auto;
}

/* Progress dots */
.steps {
  display: flex;
  align-items: center;
  justify-content: space-between;
  list-style: none;
  counter-reset: step;
  margin: 0.5rem 0 1.5rem;
  padding: 0;
}

.steps__item {
  counter-increment: step;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.35rem;
  flex: 1;
  position: relative;
  font-size: 0.72rem;
  color: var(--color-muted);
  text-align: center;
}

/* connecting line */
.steps__item::after {
  content: "";
  position: absolute;
  top: 13px;
  left: calc(50% + 16px);
  right: calc(-50% + 16px);
  height: 2px;
  background: var(--color-border);
  z-index: 0;
}
.steps__item:last-child::after {
  display: none;
}

.steps__item::before {
  content: counter(step);
  display: grid;
  place-items: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  color: var(--color-muted);
  font-weight: 700;
  font-size: 0.8rem;
  position: relative;
  z-index: 1;
  transition: all 0.2s ease;
}

.steps__item.is-active::before {
  border-color: var(--color-accent);
  color: var(--color-accent);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--color-accent) 18%, transparent);
}
.steps__item.is-done::before {
  content: "✓";
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-text);
}
.steps__item.is-active span,
.steps__item.is-done span {
  color: var(--color-text);
  font-weight: 600;
}

/* --------------------------------------------------------------------------
   Card / step
   -------------------------------------------------------------------------- */

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.75rem;
  animation: rise 0.25s ease both;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (prefers-reduced-motion: reduce) {
  .card {
    animation: none;
  }
  * {
    scroll-behavior: auto !important;
  }
}

.step__title {
  font-size: 1.6rem;
  letter-spacing: -0.01em;
}

.step__lead {
  color: var(--color-muted);
  margin-top: 0.4rem;
}

.step__actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 1.75rem;
}

/* --------------------------------------------------------------------------
   Fields & inputs
   -------------------------------------------------------------------------- */

.field {
  margin-top: 1.5rem;
}

.field label,
.field__label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.field__hint {
  margin-top: 0.6rem;
  font-size: 0.85rem;
  color: var(--color-muted);
}

input[type="number"],
input[type="text"] {
  font: inherit;
  color: var(--color-text);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 0.7rem 0.85rem;
  width: 100%;
}

input::placeholder {
  color: var(--color-muted);
  opacity: 0.7;
}

input:focus {
  border-color: var(--color-accent);
}

input.is-invalid {
  border-color: var(--color-danger);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-danger) 22%, transparent);
}

.inline-select,
.inline-select:focus {
  font: inherit;
  color: var(--color-text);
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 0.15rem 0.35rem;
}

/* Money input with a leading symbol */
.money-input {
  display: flex;
  align-items: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  overflow: hidden;
}
.money-input:focus-within {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-accent) 16%, transparent);
}
.money-input__symbol {
  padding: 0 0.4rem 0 0.85rem;
  color: var(--color-muted);
  font-weight: 600;
  white-space: nowrap;
}
.money-input input {
  border: none;
  border-radius: 0;
  background: transparent;
}
.money-input input:focus {
  box-shadow: none;
}

/* Stepper for people count */
.stepper {
  display: inline-flex;
  align-items: stretch;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  overflow: hidden;
  max-width: 12rem;
}
.stepper__btn {
  font: inherit;
  font-size: 1.3rem;
  line-height: 1;
  width: 3rem;
  border: none;
  background: color-mix(in srgb, var(--color-accent) 8%, transparent);
  color: var(--color-accent);
  cursor: pointer;
}
.stepper__btn:hover {
  background: color-mix(in srgb, var(--color-accent) 16%, transparent);
}
.stepper input {
  border: none;
  border-radius: 0;
  text-align: center;
  width: 4rem;
  -moz-appearance: textfield;
}
.stepper input::-webkit-outer-spin-button,
.stepper input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

/* --------------------------------------------------------------------------
   Buttons & chips
   -------------------------------------------------------------------------- */

.btn {
  font: inherit;
  font-weight: 600;
  cursor: pointer;
  border-radius: var(--radius-sm);
  padding: 0.7rem 1.4rem;
  border: 1px solid transparent;
  transition: transform 0.05s ease, background 0.15s ease;
}
.btn:active {
  transform: translateY(1px);
}

.btn--primary {
  background: var(--color-accent);
  color: var(--color-accent-text);
}
.btn--primary:hover {
  background: color-mix(in srgb, var(--color-accent) 85%, #000);
}

.btn--ghost {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border);
}
.btn--ghost:hover {
  background: color-mix(in srgb, var(--color-text) 6%, transparent);
}

.tip-options {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}
.chip {
  font: inherit;
  font-weight: 600;
  cursor: pointer;
  padding: 0.55rem 1.1rem;
  border-radius: 999px;
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text);
}
.chip:hover {
  border-color: var(--color-accent);
}
.chip.is-selected {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-text);
}

/* --------------------------------------------------------------------------
   Payers (step 4)
   -------------------------------------------------------------------------- */

.payers {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-top: 1.25rem;
}
.payer {
  display: grid;
  grid-template-columns: 1fr 9.5rem;
  gap: 0.75rem;
}
.payer__name input {
  width: 100%;
}

.paid-summary {
  margin-top: 1.1rem;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-muted);
}
.paid-summary.is-ok {
  color: var(--color-credit);
}
.paid-summary.is-warn {
  color: var(--color-debit);
}

/* --------------------------------------------------------------------------
   Result (step 5)
   -------------------------------------------------------------------------- */

.summary {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.6rem;
  margin: 1.25rem 0;
}
.summary__tile {
  background: color-mix(in srgb, var(--color-accent) 6%, transparent);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 0.75rem 0.5rem;
  text-align: center;
}
.summary__label {
  display: block;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-muted);
}
.summary__value {
  display: block;
  font-weight: 700;
  font-size: 1.05rem;
  margin-top: 0.2rem;
}

.settlements {
  list-style: none;
  margin: 1rem 0 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}
.settlement {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto;
  align-items: center;
  gap: 0.6rem;
  padding: 0.85rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  box-shadow: var(--shadow-sm);
}
.settlement__from {
  font-weight: 600;
  color: var(--color-debit);
}
.settlement__to {
  font-weight: 600;
  color: var(--color-credit);
}
.settlement__arrow {
  color: var(--color-muted);
}
.settlement__amount {
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.balances {
  margin-top: 1.25rem;
  border-top: 1px solid var(--color-border);
  padding-top: 0.75rem;
}
.balances summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--color-muted);
}
.balances__body {
  margin-top: 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}
.balance {
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: 0.75rem;
  align-items: baseline;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  background: color-mix(in srgb, var(--color-text) 3%, transparent);
}
.balance__name {
  font-weight: 600;
}
.balance__paid {
  color: var(--color-muted);
  font-size: 0.85rem;
  font-variant-numeric: tabular-nums;
}
.balance__status {
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}
.balance.is-credit {
  background: var(--color-credit-bg);
}
.balance.is-credit .balance__status {
  color: var(--color-credit);
}
.balance.is-debit {
  background: var(--color-debit-bg);
}
.balance.is-debit .balance__status {
  color: var(--color-debit);
}

/* --------------------------------------------------------------------------
   Generic content pages (About etc.)
   -------------------------------------------------------------------------- */

.prose {
  max-width: var(--max-width);
  width: 100%;
  margin: 0 auto;
  padding: 0.5rem 1.25rem 1rem;
  flex: 1 0 auto;
}
.prose .card {
  animation: none;
}
.prose h1 {
  font-size: 1.8rem;
  margin-bottom: 0.5rem;
}
.prose h2 {
  font-size: 1.2rem;
  margin: 1.5rem 0 0.5rem;
}
.prose p,
.prose li {
  color: var(--color-text);
}
.prose p {
  margin-top: 0.75rem;
}
.prose ul,
.prose ol {
  margin: 0.5rem 0 0;
  padding-left: 1.25rem;
}
.prose li {
  margin: 0.35rem 0;
}
.prose .muted {
  color: var(--color-muted);
}

/* --------------------------------------------------------------------------
   Small screens
   -------------------------------------------------------------------------- */

@media (max-width: 560px) {
  .card {
    padding: 1.35rem;
  }
  .summary {
    grid-template-columns: repeat(2, 1fr);
  }
  .steps__item span {
    display: none;
  }
  .steps__item.is-active span {
    display: block;
  }
  .settlement {
    grid-template-columns: 1fr auto 1fr;
  }
  .settlement__amount {
    grid-column: 1 / -1;
    text-align: right;
    padding-top: 0.25rem;
    border-top: 1px dashed var(--color-border);
  }
}