:root {
  color-scheme: light;
  --background: #f6f8fb;
  --surface: #ffffff;
  --surface-soft: #eef4f8;
  --surface-strong: #0f2f3a;
  --text: #17313b;
  --muted: #637785;
  --border: #d8e2e8;
  --accent: #0f766e;
  --accent-dark: #115e59;
  --accent-soft: #d9f3ef;
  --danger: #b42318;
  --danger-soft: #fff1f0;
  --success: #047857;
  --warning: #a15c07;
  --warning-soft: #fff7e6;
  --shadow: 0 24px 60px rgba(15, 47, 58, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  line-height: 1.5;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(15, 118, 110, 0.15), transparent 34rem),
    linear-gradient(180deg, #f8fbfd 0%, var(--background) 48%, #edf4f7 100%);
}

button,
input {
  font: inherit;
}

button {
  cursor: pointer;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
}

a {
  color: var(--accent);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.2em;
}

code {
  font-size: 0.95em;
}

.page-shell {
  width: min(100% - 2rem, 1180px);
  margin: 0 auto;
  padding: 4rem 0 2rem;
}

.hero {
  min-height: 18rem;
  margin-bottom: 2rem;
  padding: clamp(1.5rem, 4vw, 2.5rem);
  border: 1px solid rgba(216, 226, 232, 0.75);
  border-radius: 1.75rem;
  background:
    linear-gradient(
      90deg,
      rgba(248, 251, 253, 0.98) 0%,
      rgba(248, 251, 253, 0.9) 42%,
      rgba(248, 251, 253, 0.45) 72%,
      rgba(248, 251, 253, 0.12) 100%
    ),
    url("backgrount.png") right center / cover no-repeat;
  box-shadow: var(--shadow);
}

.eyebrow {
  margin: 0 0 0.7rem;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.brand-logo {
  display: block;
  width: min(12rem, 52vw);
  height: auto;
  margin-bottom: 1.25rem;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 780px;
  margin-bottom: 1rem;
  font-size: clamp(2.45rem, 6vw, 5rem);
  line-height: 0.95;
  letter-spacing: -0.055em;
}

h2 {
  margin-bottom: 0.4rem;
  font-size: clamp(1.25rem, 2vw, 1.55rem);
}

.intro {
  max-width: 680px;
  margin-bottom: 0;
  color: var(--muted);
  font-size: 1.1rem;
}

.calculator-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(20rem, 0.75fr);
  gap: 1rem;
  align-items: start;
}

.calculator-card,
.result-card,
.info-card,
.faq-card,
.disclaimer-card {
  border: 1px solid var(--border);
  border-radius: 1.5rem;
  background: rgba(255, 255, 255, 0.9);
  box-shadow: var(--shadow);
  backdrop-filter: blur(12px);
}

.calculator-card,
.result-card {
  padding: clamp(1rem, 3vw, 1.5rem);
}

.result-card {
  position: sticky;
  top: 1rem;
}

.section-heading {
  margin-bottom: 1.25rem;
}

.section-heading p:not(.eyebrow) {
  margin-bottom: 0;
  color: var(--muted);
}

.step-card {
  display: grid;
  gap: 1rem;
  margin: 0 0 1rem;
  padding: 1.1rem;
  border: 1px solid var(--border);
  border-radius: 1.2rem;
  background: #fbfdfe;
}

.step-card legend {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0 0.35rem;
  font-weight: 800;
}

.step-number {
  display: inline-grid;
  width: 1.75rem;
  height: 1.75rem;
  place-items: center;
  border-radius: 50%;
  color: #ffffff;
  background: var(--accent);
  font-size: 0.9rem;
}

.segmented-control,
.unit-toggle {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.5rem;
}

.unit-toggle {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  align-self: end;
}

.segmented-control input,
.unit-toggle input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.segmented-control span,
.unit-toggle span,
.preset-button,
.example-button {
  display: inline-flex;
  min-height: 2.75rem;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--text);
  background: var(--surface);
  font-weight: 800;
  text-align: center;
  transition:
    background-color 160ms ease,
    border-color 160ms ease,
    color 160ms ease,
    transform 160ms ease;
}

.segmented-control input:checked + span,
.unit-toggle input:checked + span,
.preset-button.active {
  border-color: var(--accent);
  color: var(--accent-dark);
  background: var(--accent-soft);
}

.segmented-control label:focus-within span,
.unit-toggle label:focus-within span,
.preset-button:focus-visible,
.example-button:focus-visible,
.primary-button:focus-visible,
.secondary-button:focus-visible,
.copy-button:focus-visible {
  outline: 3px solid rgba(15, 118, 110, 0.22);
  outline-offset: 2px;
}

.preset-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.5rem;
}

.preset-button,
.example-button {
  padding: 0.65rem 0.85rem;
}

.preset-button:hover,
.example-button:hover {
  border-color: var(--accent);
  color: var(--accent-dark);
}

.field-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(9rem, 12rem);
  gap: 0.75rem;
}

.field {
  display: grid;
  gap: 0.45rem;
  color: var(--text);
  font-weight: 800;
}

.input-with-unit {
  display: flex;
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: 0.95rem;
  background: var(--surface);
}

.input-with-unit:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 4px rgba(15, 118, 110, 0.12);
}

.input-with-unit input {
  width: 100%;
  min-width: 0;
  border: 0;
  padding: 0.85rem 1rem;
  color: var(--text);
  background: transparent;
  outline: 0;
}

.input-with-unit > span {
  display: inline-flex;
  align-items: center;
  padding: 0 1rem;
  color: var(--muted);
  border-left: 1px solid var(--border);
  background: var(--surface-soft);
  font-weight: 800;
}

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

.validation-message,
.copy-status,
.warning-message {
  min-height: 1.5rem;
  margin: 0.75rem 0 0;
  font-size: 0.95rem;
}

.validation-message {
  color: var(--danger);
}

.warning-message {
  min-height: 0;
  padding: 0.8rem 0.95rem;
  border: 1px solid #ffd591;
  border-radius: 1rem;
  color: var(--warning);
  background: var(--warning-soft);
}

.warning-message:empty {
  display: none;
}

.copy-status {
  color: var(--success);
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  margin-top: 1rem;
}

.primary-button,
.secondary-button,
.copy-button {
  border: 1px solid transparent;
  border-radius: 999px;
  padding: 0.8rem 1.1rem;
  font-weight: 800;
  transition:
    background-color 160ms ease,
    border-color 160ms ease,
    color 160ms ease,
    transform 160ms ease;
}

.primary-button,
.copy-button {
  color: #ffffff;
  background: var(--accent);
}

.primary-button:hover,
.copy-button:hover {
  background: var(--accent-dark);
}

.secondary-button {
  color: var(--text);
  border-color: var(--border);
  background: var(--surface);
}

.secondary-button:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.primary-button:active,
.secondary-button:active,
.preset-button:active,
.copy-button:active,
.example-button:active {
  transform: translateY(1px);
}

.result-list {
  display: grid;
  gap: 0.65rem;
  margin: 0;
}

.result-list div {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--border);
}

.result-list div:last-child {
  border-bottom: 0;
}

.result-list dt {
  color: var(--muted);
  font-weight: 700;
}

.result-list dd {
  margin: 0;
  font-weight: 900;
  text-align: right;
}

.copy-button {
  width: 100%;
  margin-top: 1.25rem;
}

.content-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

.info-card,
.faq-card,
.disclaimer-card {
  padding: clamp(1.25rem, 3vw, 1.75rem);
}

.clean-list {
  display: grid;
  gap: 0.75rem;
  margin: 1rem 0 0;
  padding: 0;
  list-style: none;
}

.clean-list li {
  padding: 0.9rem 1rem;
  border: 1px solid var(--border);
  border-radius: 1rem;
  background: var(--surface-soft);
  font-weight: 800;
}

.example-list {
  display: grid;
  gap: 0.75rem;
  margin-top: 1rem;
}

.example-button {
  justify-content: flex-start;
  border-radius: 1rem;
  padding: 0.9rem 1rem;
  text-align: left;
}

.faq-card,
.disclaimer-card {
  margin-top: 1rem;
}

details {
  border-top: 1px solid var(--border);
}

details:last-child {
  border-bottom: 1px solid var(--border);
}

summary {
  padding: 1rem 0;
  cursor: pointer;
  font-weight: 900;
}

details p {
  margin-bottom: 1rem;
  color: var(--muted);
}

.disclaimer-card {
  color: #7a271a;
  background: var(--danger-soft);
  border-color: #ffccc7;
  box-shadow: none;
}

.disclaimer-card p {
  margin-bottom: 0;
  font-weight: 800;
}

.site-footer {
  width: min(100% - 2rem, 1180px);
  margin: 0 auto;
  padding: 0 0 3rem;
  color: var(--muted);
  text-align: center;
}

@media (max-width: 940px) {
  .calculator-layout,
  .content-grid {
    grid-template-columns: 1fr;
  }

  .result-card {
    position: static;
  }
}

@media (max-width: 620px) {
  .page-shell {
    width: min(100% - 1rem, 1180px);
    padding-top: 2.25rem;
  }

  .brand-logo {
    width: min(10rem, 60vw);
  }

  .preset-grid,
  .segmented-control,
  .field-row {
    grid-template-columns: 1fr;
  }

  .unit-toggle {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .result-list div {
    display: grid;
    gap: 0.25rem;
  }

  .result-list dd {
    text-align: left;
  }
}