:root {
  --color-primary-900: #0f3d3e;
  --color-primary-800: #165b5c;
  --color-primary-700: #1f7a7b;
  --color-primary-600: #2f9e8f;
  --color-accent-500: #f4b860;
  --color-success: #22c55e;
  --color-success-soft: #dcfce7;
  --color-error: #ef4444;
  --color-error-soft: #fee2e2;
  --color-warning: #f59e0b;
  --color-warning-soft: #fef3c7;
  --color-info: #2563eb;
  --color-info-soft: #dbeafe;
  --color-text: #1f2937;
  --color-text-light: #52606d;
  --color-white: #ffffff;
  --color-surface: rgba(255, 255, 255, 0.82);
  --color-surface-strong: rgba(255, 255, 255, 0.94);
  --color-surface-muted: rgba(255, 255, 255, 0.7);
  --color-border: rgba(23, 64, 70, 0.14);
  --color-overlay: rgba(15, 61, 62, 0.08);

  --spacing-2xs: 0.25rem;
  --spacing-xs: 0.5rem;
  --spacing-sm: 0.75rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4.5rem;

  --radius-sm: 0.375rem;
  --radius: 0.5rem;
  --radius-lg: 0.75rem;

  --shadow-sm: 0 10px 24px rgba(15, 61, 62, 0.08);
  --shadow-md: 0 20px 44px rgba(15, 61, 62, 0.12);
  --shadow-lg: 0 36px 72px rgba(15, 61, 62, 0.16);

  --transition-base: 180ms ease;
  --transition-slow: 280ms ease;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--color-text);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.2) 0%, rgba(255, 255, 255, 0) 22%),
    linear-gradient(135deg, #effbf6 0%, #d8efe8 28%, #c6e7ea 58%, #edf8f2 100%);
  line-height: 1.6;
}

img,
svg {
  display: block;
  max-width: 100%;
}

button,
input,
select,
textarea {
  font: inherit;
}

button {
  -webkit-tap-highlight-color: transparent;
}

.container {
  width: min(100%, 1200px);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.hidden {
  display: none;
}

.page {
  display: flex;
  flex-direction: column;
  position: relative;
  overflow-x: hidden;
}

.page::before {
  content: "";
  position: fixed;
  inset: 0;
  background:
    linear-gradient(115deg, rgba(47, 158, 143, 0.08), transparent 38%),
    linear-gradient(240deg, rgba(244, 184, 96, 0.08), transparent 34%);
  pointer-events: none;
  z-index: -1;
}

.page__main {
  flex: 1;
  padding-bottom: var(--spacing-2xl);
}

.header {
  padding: var(--spacing-2xl) 0 var(--spacing-xl);
}

.header__content {
  text-align: center;
}

.header__title {
  color: var(--color-primary-900);
  font-size: clamp(2rem, 5vw, 3.4rem);
  line-height: 1.08;
  margin-bottom: var(--spacing-sm);
}

.header__subtitle {
  max-width: 46rem;
  margin: 0 auto;
  color: var(--color-text-light);
  font-size: 1.05rem;
}

.calculator {
  padding: var(--spacing-md) 0 var(--spacing-xl);
}

.calculator__content,
.results__content,
.comparison__content,
.carbon-credits__content {
  background: var(--color-surface);
  backdrop-filter: blur(16px);
  border: 1px solid rgba(255, 255, 255, 0.48);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
}

.calculator__content {
  padding: clamp(1.5rem, 3vw, 2.5rem);
}

.calculator__title {
  font-size: clamp(1.4rem, 3vw, 2rem);
  margin-bottom: var(--spacing-lg);
  color: var(--color-primary-900);
}

.calculator__form {
  display: grid;
  gap: var(--spacing-lg);
}

.form__group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.form__group--inline {
  flex-direction: row;
  align-items: center;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.form__label,
.form__legend {
  font-weight: 700;
  color: var(--color-primary-900);
}

.form__label--checkbox {
  font-weight: 500;
  color: var(--color-text);
}

.form__input {
  width: 100%;
  min-height: 3.25rem;
  padding: 0.875rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface-strong);
  color: var(--color-text);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.6);
  transition:
    border-color var(--transition-base),
    box-shadow var(--transition-base),
    background-color var(--transition-base),
    transform var(--transition-base);
}

.form__input::placeholder {
  color: #8a97a4;
}

.form__input:hover {
  border-color: rgba(31, 122, 123, 0.28);
}

.form__input:focus {
  outline: none;
  border-color: rgba(37, 99, 235, 0.5);
  box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.14);
}

.form__input[readonly] {
  background: rgba(31, 122, 123, 0.06);
  color: var(--color-text-light);
}

.form__helper-text {
  font-size: 0.95rem;
  color: var(--color-text-light);
}

.form__checkbox,
.transport-selector__input {
  accent-color: var(--color-primary-700);
}

.transport-selector {
  border: 0;
  padding: 0;
}

.transport-selector__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-sm);
}

.transport-selector__option {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  min-height: 4.5rem;
  padding: var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface-strong);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition:
    transform var(--transition-base),
    box-shadow var(--transition-base),
    border-color var(--transition-base),
    background-color var(--transition-base);
}

.transport-selector__option:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: rgba(31, 122, 123, 0.3);
}

.transport-selector__option:has(.transport-selector__input:checked) {
  border-color: rgba(31, 122, 123, 0.5);
  background: linear-gradient(180deg, rgba(47, 158, 143, 0.09), rgba(255, 255, 255, 0.96));
  box-shadow: 0 0 0 4px rgba(47, 158, 143, 0.12);
}

.transport-selector__label {
  font-weight: 600;
  color: var(--color-text);
}

.form__actions {
  display: flex;
  justify-content: flex-start;
}

.form__submit {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  min-height: 3.25rem;
  border: 0;
  border-radius: var(--radius);
  padding: 0.95rem 1.4rem;
  background: linear-gradient(135deg, var(--color-primary-800), var(--color-primary-600));
  color: var(--color-white);
  font-weight: 700;
  box-shadow: var(--shadow-md);
  cursor: pointer;
  transition:
    transform var(--transition-base),
    box-shadow var(--transition-base),
    filter var(--transition-base),
    opacity var(--transition-base);
}

.form__submit:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  filter: saturate(1.08);
}

.form__submit:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.18);
  outline-offset: 3px;
}

.form__submit:disabled {
  cursor: wait;
  opacity: 0.86;
  transform: none;
}

.results,
.comparison,
.carbon-credits {
  margin-top: var(--spacing-lg);
  animation: fade-up var(--transition-slow);
}

.results__content,
.comparison__content,
.carbon-credits__content {
  min-height: 5rem;
  padding: var(--spacing-lg);
}

.results__grid,
.carbon-credits__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--spacing-md);
}

.results__card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: var(--spacing-xs);
  min-height: 9.25rem;
  padding: 1.15rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.98), rgba(245, 251, 249, 0.92));
  box-shadow: var(--shadow-sm);
  transition:
    transform var(--transition-base),
    box-shadow var(--transition-base),
    border-color var(--transition-base);
}

.results__card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: rgba(31, 122, 123, 0.22);
}

.results__card-header {
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-primary-700);
}

.results__card-value {
  font-size: clamp(1.1rem, 2vw, 1.5rem);
  font-weight: 700;
  line-height: 1.25;
  color: var(--color-primary-900);
  overflow-wrap: anywhere;
}

.results__card-detail {
  font-size: 0.96rem;
  color: var(--color-text-light);
}

.comparison__list {
  display: grid;
  gap: var(--spacing-md);
}

.comparison__item {
  display: grid;
  gap: var(--spacing-sm);
  padding: 1rem 1.1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.98), rgba(247, 251, 250, 0.92));
  box-shadow: var(--shadow-sm);
  transition:
    transform var(--transition-base),
    box-shadow var(--transition-base),
    border-color var(--transition-base);
}

.comparison__item:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.comparison__item--selected {
  border-color: rgba(34, 197, 94, 0.36);
  box-shadow: 0 0 0 4px rgba(34, 197, 94, 0.1), var(--shadow-md);
}

.comparison__header,
.comparison__stats {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.comparison__title,
.comparison__emission {
  font-weight: 700;
  color: var(--color-primary-900);
}

.comparison__percentage {
  color: var(--color-text-light);
  font-weight: 600;
}

.comparison__badge {
  padding: 0.28rem 0.65rem;
  border-radius: 999px;
  background: var(--color-success-soft);
  color: #15703b;
  font-size: 0.82rem;
  font-weight: 700;
}

.comparison__progress {
  width: 100%;
  height: 0.7rem;
  border-radius: 999px;
  background: rgba(15, 61, 62, 0.08);
  overflow: hidden;
}

.comparison__progress-bar {
  height: 100%;
  border-radius: inherit;
  transition: width 420ms ease, background-color var(--transition-base);
}

.comparison__tip,
.carbon-credits__info {
  margin-top: var(--spacing-md);
  padding: 1rem 1.1rem;
  border: 1px solid rgba(37, 99, 235, 0.12);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(219, 234, 254, 0.55), rgba(255, 255, 255, 0.9));
  color: #23425b;
}

.carbon-credits__grid {
  margin-bottom: var(--spacing-md);
}

.carbon-credits__actions {
  display: flex;
  justify-content: flex-start;
  margin-top: var(--spacing-lg);
}

.spinner {
  width: 1rem;
  height: 1rem;
  border: 2px solid rgba(255, 255, 255, 0.34);
  border-top-color: var(--color-white);
  border-radius: 999px;
  animation: spin 700ms linear infinite;
}

.footer {
  padding: var(--spacing-lg) 0;
  background: rgba(15, 61, 62, 0.9);
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.footer__credits {
  text-align: center;
  color: rgba(255, 255, 255, 0.82);
  font-size: 0.95rem;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

@keyframes fade-up {
  from {
    opacity: 0;
    transform: translateY(14px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 900px) {
  .results__grid,
  .carbon-credits__grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 var(--spacing-md);
  }

  .header {
    padding-top: 2.75rem;
  }

  .calculator__content,
  .results__content,
  .comparison__content,
  .carbon-credits__content {
    padding: var(--spacing-lg);
  }

  .transport-selector__grid {
    grid-template-columns: 1fr;
  }

  .form__actions,
  .carbon-credits__actions {
    justify-content: stretch;
  }

  .form__submit {
    width: 100%;
  }
}

@media (max-width: 480px) {
  .header__subtitle {
    font-size: 1rem;
  }

  .transport-selector__option {
    min-height: 4rem;
    padding: 0.875rem;
  }

  .results__card,
  .comparison__item {
    padding: 0.95rem;
  }

  .comparison__header,
  .comparison__stats {
    align-items: flex-start;
  }

  .footer__credits {
    font-size: 0.875rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}