:root {
  --font-title: 'Poppins', sans-serif;
  --font-body: 'Inter', sans-serif;

  --color-orange: #E67E22;
  --color-orange-dark: #D35400;
  --color-green: #27AE60;
  --color-green-dark: #1E8449;
  --color-cream: #FFF8F0;
  --color-cream-dark: #F5E6D3;

  --radius-sm: 12px;
  --radius-md: 16px;
  --radius-lg: 20px;
  --shadow-soft: 0 4px 20px rgba(0, 0, 0, 0.08);
  --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.12);
  --shadow-inset: inset 0 2px 4px rgba(0, 0, 0, 0.06);

  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;
}

[data-theme="light"] {
  --bg-body: #F2F0EB;
  --bg-card: #FFFFFF;
  --bg-input: #FAFAFA;
  --bg-header: #FFFFFF;
  --text-primary: #2D2D2D;
  --text-secondary: #6B6B6B;
  --text-muted: #9E9E9E;
  --border-color: #E8E4DE;
  --border-focus: var(--color-orange);
  --btn-primary-bg: var(--color-orange);
  --btn-primary-text: #FFFFFF;
  --btn-secondary-bg: var(--color-cream);
  --btn-secondary-text: var(--color-orange-dark);
  --accent-green: var(--color-green);
  --shadow-color: rgba(0, 0, 0, 0.08);
}

[data-theme="dark"] {
  --bg-body: #1A1816;
  --bg-card: #252320;
  --bg-input: #2E2B28;
  --bg-header: #252320;
  --text-primary: #F0EBE3;
  --text-secondary: #B8B0A6;
  --text-muted: #8A8279;
  --border-color: #3D3833;
  --border-focus: var(--color-orange);
  --btn-primary-bg: var(--color-orange);
  --btn-primary-text: #FFFFFF;
  --btn-secondary-bg: #3D3833;
  --btn-secondary-text: var(--color-orange);
  --accent-green: var(--color-green);
  --shadow-color: rgba(0, 0, 0, 0.25);
}

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  color: var(--text-primary);
  background-color: var(--bg-body);
  min-height: 100vh;
  line-height: 1.5;
  transition: background-color var(--transition-slow);
}

.page-wrapper {
  max-width: 480px;
  margin: 0 auto;
  padding: 0 16px;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* Header */
.site-header {
  padding: 20px 0 16px;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-family: var(--font-title);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-orange);
  letter-spacing: -0.02em;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.theme-toggle {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  border: none;
  background-color: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-soft);
  transition: transform var(--transition-base), box-shadow var(--transition-base), background-color var(--transition-base);
}

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

.theme-toggle:focus-visible {
  outline: 3px solid var(--color-orange);
  outline-offset: 2px;
}

.icon-moon {
  display: none;
}

[data-theme="dark"] .icon-sun {
  display: none;
}

[data-theme="dark"] .icon-moon {
  display: block;
}

/* Main */
.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 20px;
  padding-bottom: 24px;
}

/* Cards */
.converter-card,
.history-card {
  background-color: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-soft);
  transition: background-color var(--transition-slow), box-shadow var(--transition-slow);
  animation: fadeIn 400ms ease both;
}

.history-card {
  animation-delay: 100ms;
}

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

@media (prefers-reduced-motion: reduce) {
  .converter-card,
  .history-card {
    animation: none;
  }
}

/* Form */
.input-group {
  margin-bottom: 16px;
}

.input-group:last-child {
  margin-bottom: 0;
}

.input-label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.input-field,
.input-select {
  width: 100%;
  height: 52px;
  padding: 0 16px;
  font-family: var(--font-body);
  font-size: 1rem;
  color: var(--text-primary);
  background-color: var(--bg-input);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  outline: none;
  transition: border-color var(--transition-base), box-shadow var(--transition-base), background-color var(--transition-slow);
  -webkit-appearance: none;
  appearance: none;
}

.input-field:hover,
.input-select:hover {
  border-color: var(--text-muted);
}

.input-field:focus,
.input-select:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(230, 126, 34, 0.15);
}

.custom-select-wrapper {
  position: relative;
}

.custom-select-wrapper::after {
  content: '';
  position: absolute;
  right: 16px;
  top: 50%;
  transform: translateY(-50%);
  width: 10px;
  height: 10px;
  border-right: 2px solid var(--text-muted);
  border-bottom: 2px solid var(--text-muted);
  transform: translateY(-70%) rotate(45deg);
  pointer-events: none;
  transition: border-color var(--transition-base);
}

.input-hint {
  display: block;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

/* Swap */
.swap-row {
  display: flex;
  justify-content: center;
  margin: 4px 0 12px;
}

.swap-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 18px;
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--btn-secondary-text);
  background-color: var(--btn-secondary-bg);
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  box-shadow: var(--shadow-soft);
  transition: transform var(--transition-base), box-shadow var(--transition-base), background-color var(--transition-base);
}

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

.swap-btn:focus-visible {
  outline: 3px solid var(--color-orange);
  outline-offset: 2px;
}

.swap-btn:active {
  transform: translateY(0);
}

/* Result */
.result-area {
  margin-top: 8px;
  padding: 20px;
  background-color: var(--bg-input);
  border-radius: var(--radius-md);
  text-align: center;
  position: relative;
  transition: background-color var(--transition-slow);
  animation: popIn 300ms ease both;
  animation-delay: 200ms;
}

@keyframes popIn {
  from {
    opacity: 0;
    transform: scale(0.96);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@media (prefers-reduced-motion: reduce) {
  .result-area {
    animation: none;
  }
}

.result-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 4px;
}

.result-value {
  font-family: var(--font-title);
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-green);
  line-height: 1.2;
  word-break: break-word;
}

.result-value.is-empty {
  color: var(--text-muted);
}

.copy-btn {
  margin-top: 12px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--btn-primary-text);
  background-color: var(--btn-primary-bg);
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  box-shadow: var(--shadow-soft);
  transition: transform var(--transition-base), box-shadow var(--transition-base), background-color var(--transition-base);
}

.copy-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
  background-color: var(--color-orange-dark);
}

.copy-btn:focus-visible {
  outline: 3px solid var(--color-green);
  outline-offset: 2px;
}

.copy-btn:active {
  transform: translateY(0);
}

.copy-feedback {
  display: block;
  font-size: 0.75rem;
  color: var(--color-green);
  margin-top: 6px;
  min-height: 1.2em;
}

/* History */
.section-title {
  font-family: var(--font-title);
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.section-subtitle {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-bottom: 14px;
}

.history-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.history-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 14px;
  background-color: var(--bg-input);
  border-radius: var(--radius-sm);
  border-left: 4px solid var(--color-orange);
  transition: transform var(--transition-base), box-shadow var(--transition-base), background-color var(--transition-slow);
}

.history-item:hover {
  transform: translateX(2px);
  box-shadow: var(--shadow-soft);
}

.history-conversion {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-primary);
}

.history-result {
  font-family: var(--font-title);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--color-green);
}

.history-empty {
  font-size: 0.875rem;
  color: var(--text-muted);
  text-align: center;
  padding: 16px 0;
}

/* Footer */
.site-footer {
  padding: 20px 0 24px;
  text-align: center;
}

.site-footer p {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* Utilities */
.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;
}

/* Responsive */
@media (min-width: 768px) {
  .page-wrapper {
    max-width: 560px;
    padding: 0 24px;
  }

  .converter-card,
  .history-card {
    padding: 28px;
  }

  .result-value {
    font-size: 2.25rem;
  }
}

@media (min-width: 1024px) {
  .page-wrapper {
    max-width: 640px;
  }

  .main-content {
    gap: 24px;
  }
}

/* Navigation */
.header-brand {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.logo-link {
  text-decoration: none;
  color: inherit;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-link {
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-muted);
  text-decoration: none;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  transition: color var(--transition-base), background-color var(--transition-base);
}

.nav-link:hover {
  color: var(--text-secondary);
  background-color: var(--bg-input);
}

.nav-link.is-active {
  color: var(--color-orange);
  background-color: var(--color-cream);
}

[data-theme="dark"] .nav-link.is-active {
  background-color: var(--btn-secondary-bg);
}

/* Diet checkboxes */
.diet-fieldset {
  border: none;
  margin: 0 0 16px;
  padding: 0;
}

.checkbox-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 6px;
}

.checkbox-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-primary);
  background-color: var(--bg-input);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: border-color var(--transition-base), box-shadow var(--transition-base), background-color var(--transition-base);
}

.checkbox-label:hover {
  border-color: var(--text-muted);
}

.checkbox-input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.checkbox-box {
  width: 18px;
  height: 18px;
  border-radius: 4px;
  border: 2px solid var(--text-muted);
  background-color: var(--bg-card);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: border-color var(--transition-base), background-color var(--transition-base);
  flex-shrink: 0;
}

.checkbox-box::after {
  content: '';
  width: 10px;
  height: 10px;
  background-color: var(--bg-card);
  border-radius: 2px;
  transform: scale(0);
  transition: transform var(--transition-base);
}

.checkbox-input:checked + .checkbox-box {
  border-color: var(--color-green);
  background-color: var(--color-green);
}

.checkbox-input:checked + .checkbox-box::after {
  content: '';
  width: 10px;
  height: 6px;
  background: transparent;
  border-left: 2px solid #fff;
  border-bottom: 2px solid #fff;
  border-radius: 0;
  transform: rotate(-45deg) scale(1);
  margin-bottom: 2px;
}

.checkbox-input:focus-visible + .checkbox-box {
  box-shadow: 0 0 0 3px rgba(39, 174, 96, 0.25);
}

/* Action row */
.action-row {
  display: flex;
  justify-content: center;
  margin-top: 4px;
}

/* Results */
.results-section {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.results-section[hidden] {
  display: none;
}

.results-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.substitute-card {
  background-color: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 20px;
  box-shadow: var(--shadow-soft);
  transition: transform var(--transition-base), box-shadow var(--transition-base), background-color var(--transition-slow);
  animation: fadeIn 400ms ease both;
  position: relative;
  overflow: hidden;
}

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

.substitute-card.is-top {
  border: 2px solid var(--color-green);
}

.substitute-card.is-top .top-badge {
  position: absolute;
  top: 0;
  right: 0;
  background-color: var(--color-green);
  color: #fff;
  font-size: 0.6875rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 4px 10px;
  border-bottom-left-radius: var(--radius-sm);
}

.substitute-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 10px;
}

.substitute-name {
  font-family: var(--font-title);
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--text-primary);
}

.substitute-amount {
  font-family: var(--font-title);
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-orange);
  white-space: nowrap;
}

.substitute-bar-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 10px;
}

.substitute-bar-track {
  flex: 1;
  height: 8px;
  background-color: var(--bg-input);
  border-radius: 999px;
  overflow: hidden;
}

.substitute-bar-fill {
  height: 100%;
  background-color: var(--color-green);
  border-radius: 999px;
  transition: width 600ms ease;
}

.substitute-bar-value {
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--color-green);
  min-width: 36px;
  text-align: right;
}

.substitute-note {
  font-size: 0.8125rem;
  color: var(--text-secondary);
  line-height: 1.45;
}

.substitute-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 10px;
}

.substitute-tag {
  font-size: 0.6875rem;
  font-weight: 600;
  color: var(--text-muted);
  background-color: var(--bg-input);
  padding: 3px 8px;
  border-radius: 6px;
  text-transform: capitalize;
}

/* Staggered animation delays for cards */
.results-list .substitute-card:nth-child(1) { animation-delay: 0ms; }
.results-list .substitute-card:nth-child(2) { animation-delay: 60ms; }
.results-list .substitute-card:nth-child(3) { animation-delay: 120ms; }
.results-list .substitute-card:nth-child(4) { animation-delay: 180ms; }
.results-list .substitute-card:nth-child(5) { animation-delay: 240ms; }
.results-list .substitute-card:nth-child(6) { animation-delay: 300ms; }

@media (prefers-reduced-motion: reduce) {
  .results-list .substitute-card {
    animation: none;
  }
  .substitute-bar-fill {
    transition: none;
  }
}

/* Language switcher */
.lang-switcher {
  display: flex;
  align-items: center;
  gap: 2px;
  padding: 3px;
  background-color: var(--bg-card);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-soft);
}

.lang-btn {
  font-family: var(--font-body);
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--text-muted);
  background-color: transparent;
  border: none;
  padding: 5px 9px;
  border-radius: 10px;
  cursor: pointer;
  transition: color var(--transition-base), background-color var(--transition-base);
}

.lang-btn:hover {
  color: var(--text-secondary);
  background-color: var(--bg-input);
}

.lang-btn.is-active {
  color: var(--color-orange);
  background-color: var(--color-cream);
}

[data-theme="dark"] .lang-btn.is-active {
  background-color: var(--btn-secondary-bg);
}

.nutrition-info {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 8px;
  padding: 8px 12px;
  background-color: var(--bg-input);
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--color-orange);
  font-size: 0.75rem;
  color: var(--text-secondary);
  transition: background-color var(--transition-slow);
}

.nutrition-icon {
  flex-shrink: 0;
  color: var(--color-orange);
}

.nutrition-value {
  font-weight: 600;
  color: var(--color-orange-dark);
}

/* Recipe specific */
.steps-list {
  list-style: none;
  counter-reset: step;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.step-item {
  position: relative;
  padding: 12px 14px 12px 44px;
  background-color: var(--bg-input);
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  color: var(--text-primary);
  line-height: 1.5;
  transition: background-color var(--transition-slow);
}

.step-item::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 24px;
  height: 24px;
  background-color: var(--color-orange);
  color: #fff;
  font-family: var(--font-title);
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.substitutions-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.substitution-item {
  padding: 10px 14px;
  background-color: var(--bg-input);
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  color: var(--text-primary);
  line-height: 1.5;
  border-left: 4px solid var(--color-green);
  transition: background-color var(--transition-slow);
}

.sub-note {
  display: block;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 2px;
}

.original-name {
  font-size: 0.8125rem;
  color: var(--text-muted);
  font-weight: 400;
}

.optional-badge {
  display: inline-block;
  font-size: 0.6875rem;
  font-weight: 700;
  color: var(--color-orange);
  background-color: var(--color-cream);
  padding: 2px 8px;
  border-radius: 6px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-top: 6px;
}

[data-theme="dark"] .optional-badge {
  background-color: var(--btn-secondary-bg);
}

.substitute-card.is-optional {
  border-left: 4px solid var(--color-orange);
}

/* Textarea */
textarea.input-field {
  height: auto;
  min-height: 120px;
  padding: 14px 16px;
  resize: vertical;
  line-height: 1.5;
}

/* Focus visible polyfill style */
:focus:not(:focus-visible) {
  outline: none;
}