/* Import Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=DM+Sans:ital,opsz,wght@0,9..40,300;0,9..40,500;0,9..40,600;0,9..40,700;1,9..40,600&family=Bricolage+Grotesque:opsz,wght@12..96,700&display=swap');

/* CSS Custom Properties */
:root {
  /* Colors from style guide */
  --neutral-900: hsl(243, 96%, 9%);
  --neutral-800: hsl(243, 27%, 20%);
  --neutral-700: hsl(243, 23%, 24%);
  --neutral-600: hsl(243, 23%, 30%);
  --neutral-300: hsl(240, 6%, 70%);
  --neutral-200: hsl(250, 6%, 84%);
  --neutral-0: hsl(0, 0%, 100%);
  --orange-500: hsl(28, 100%, 52%);
  --blue-500: hsl(233, 67%, 56%);
  --blue-700: hsl(248, 70%, 36%);

  /* Typography */
  --font-body: 'DM Sans', sans-serif;
  --font-display: 'Bricolage Grotesque', sans-serif;
  --font-size-base: 18px;

  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 0.75rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;

  /* Border radius */
  --radius-sm: 0.5rem;
  --radius-md: 1rem;
  --radius-lg: 1.5rem;
  --radius-xl: 2rem;
}

/* Reset and base styles */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-body);
  font-size: var(--font-size-base);
  font-weight: 500;
  line-height: 1.6;
  color: var(--neutral-0);
  background-color: var(--neutral-900);
  min-height: 100vh;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
}

input {
  font-family: inherit;
  border: none;
  outline: none;
}

/* App Layout */
.app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  padding: var(--spacing-lg);
  max-width: 1440px;
  margin: 0 auto;
}

/* Header */
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-3xl);
  position: relative;
}

.header__brand {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.header__logo {
  width: 40px;
  height: 40px;
}

.header__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.125rem;
  color: var(--neutral-0);
}

/* Units Dropdown */
.units-dropdown {
  position: relative;
}

.units-dropdown__toggle {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--neutral-800);
  border-radius: var(--radius-sm);
  color: var(--neutral-0);
  font-weight: 500;
  transition: background-color 0.2s ease;
}

.units-dropdown__toggle:hover {
  background: var(--neutral-700);
}

.units-dropdown__toggle:focus {
  outline: 2px solid var(--blue-500);
  outline-offset: 2px;
}

.units-dropdown__icon {
  width: 20px;
  height: 20px;
}

.units-dropdown__arrow {
  width: 16px;
  height: 16px;
  transition: transform 0.2s ease;
}

.units-dropdown__toggle[aria-expanded="true"] .units-dropdown__arrow {
  transform: rotate(180deg);
}

.units-dropdown__content {
  position: absolute;
  top: calc(100% + var(--spacing-sm));
  right: 0;
  background: var(--neutral-800);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  min-width: 240px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all 0.2s ease;
  z-index: 10;
}

.units-dropdown__toggle[aria-expanded="true"] + .units-dropdown__content {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.units-dropdown__section {
  margin-bottom: var(--spacing-lg);
}

.units-dropdown__section:last-child {
  margin-bottom: 0;
}

.units-dropdown__section-title {
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--neutral-200);
  font-size: 0.875rem;
}

.units-dropdown__option {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-xs) 0;
  cursor: pointer;
  font-size: 0.875rem;
  position: relative;
}

.units-dropdown__option input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.units-dropdown__checkmark {
  width: 20px;
  height: 20px;
  border: 2px solid var(--neutral-600);
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
}

.units-dropdown__option input:checked + .units-dropdown__checkmark {
  background: var(--blue-500);
  border-color: var(--blue-500);
}

.units-dropdown__checkmark img {
  width: 12px;
  height: 12px;
  opacity: 0;
  transition: opacity 0.2s ease;
}

.units-dropdown__option input:checked + .units-dropdown__checkmark img {
  opacity: 1;
}

/* Main Content */
.content {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-2xl);
}

/* Search Section */
.search-section {
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

.search-section__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(2rem, 5vw, 3rem);
  margin-bottom: var(--spacing-xl);
  color: var(--neutral-0);
}

.search-form {
  display: flex;
  gap: var(--spacing-md);
  max-width: 600px;
  margin: 0 auto;
}

.search-form__input-group {
  flex: 1;
  position: relative;
  display: flex;
  align-items: center;
}

.search-form__icon {
  position: absolute;
  left: var(--spacing-md);
  width: 20px;
  height: 20px;
  z-index: 1;
}

.search-form__input {
  width: 100%;
  padding: var(--spacing-md) var(--spacing-md) var(--spacing-md) 3rem;
  background: var(--neutral-800);
  border-radius: var(--radius-sm);
  color: var(--neutral-0);
  font-size: 1rem;
  transition: background-color 0.2s ease;
}

.search-form__input::placeholder {
  color: var(--neutral-300);
}

.search-form__input:focus {
  background: var(--neutral-700);
  outline: 2px solid var(--blue-500);
  outline-offset: 2px;
}

.search-form__button {
  padding: var(--spacing-md) var(--spacing-xl);
  background: var(--blue-500);
  color: var(--neutral-0);
  border-radius: var(--radius-sm);
  font-weight: 600;
  transition: background-color 0.2s ease;
}

.search-form__button:hover {
  background: var(--blue-700);
}

.search-form__button:focus {
  outline: 2px solid var(--blue-500);
  outline-offset: 2px;
}

/* Weather Display */
.weather-display {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
}

/* Current Weather Card */
.current-weather {
  background: linear-gradient(135deg, var(--blue-500), var(--blue-700));
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  position: relative;
  overflow: hidden;
  min-height: 280px;
}

.current-weather__background {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  opacity: 0.1;
}

.current-weather__bg-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.current-weather__content {
  position: relative;
  z-index: 2;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.current-weather__location {
  margin-bottom: var(--spacing-lg);
}

.current-weather__city {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.5rem;
  margin-bottom: var(--spacing-xs);
}

.current-weather__date {
  color: var(--neutral-200);
  font-size: 0.875rem;
}

.current-weather__main {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
}

.current-weather__icon {
  width: 80px;
  height: 80px;
}

.current-weather__temp {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 4rem;
  line-height: 1;
}

/* Weather Metrics */
.weather-metrics {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-md);
}

.weather-metric {
  background: var(--neutral-800);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  text-align: center;
}

.weather-metric__label {
  display: block;
  color: var(--neutral-300);
  font-size: 0.875rem;
  margin-bottom: var(--spacing-xs);
}

.weather-metric__value {
  display: block;
  font-weight: 700;
  font-size: 1.25rem;
}

/* Forecasts */
.forecasts {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xl);
}

/* Daily Forecast */
.daily-forecast {
  background: var(--neutral-800);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
}

.daily-forecast__title {
  font-weight: 600;
  margin-bottom: var(--spacing-lg);
  color: var(--neutral-200);
}

.daily-forecast__list {
  display: flex;
  justify-content: space-between;
  gap: var(--spacing-sm);
}

.daily-forecast__item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-sm);
  text-align: center;
}

.daily-forecast__day {
  font-size: 0.875rem;
  color: var(--neutral-300);
  font-weight: 600;
}

.daily-forecast__icon {
  width: 40px;
  height: 40px;
}

.daily-forecast__temps {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.daily-forecast__high {
  font-weight: 700;
  font-size: 0.875rem;
}

.daily-forecast__low {
  font-size: 0.875rem;
  color: var(--neutral-300);
}

/* Hourly Forecast */
.hourly-forecast {
  background: var(--neutral-800);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
}

.hourly-forecast__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-lg);
}

.hourly-forecast__title {
  font-weight: 600;
  color: var(--neutral-200);
}

.hourly-forecast__day-selector {
  background: var(--neutral-700);
  color: var(--neutral-0);
  border-radius: var(--radius-sm);
  padding: var(--spacing-xs) var(--spacing-sm);
  font-size: 0.875rem;
  cursor: pointer;
}

.hourly-forecast__day-selector:focus {
  outline: 2px solid var(--blue-500);
  outline-offset: 2px;
}

.hourly-forecast__list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.hourly-forecast__item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-sm) 0;
}

.hourly-forecast__time {
  font-size: 0.875rem;
  color: var(--neutral-300);
  min-width: 60px;
}

.hourly-forecast__icon {
  width: 32px;
  height: 32px;
}

.hourly-forecast__temp {
  font-weight: 700;
  min-width: 40px;
  text-align: right;
}

/* Attribution */
.attribution {
  font-size: 11px;
  text-align: center;
  margin-top: var(--spacing-xl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--neutral-800);
  color: var(--neutral-300);
}

.attribution a {
  color: var(--blue-500);
  text-decoration: none;
  transition: color 0.2s ease;
}

.attribution a:hover {
  color: var(--orange-500);
}

/* Responsive Design */
@media (max-width: 1024px) {
  .weather-display {
    grid-template-columns: 1fr;
  }

  .forecasts {
    grid-template-columns: 1fr;
  }

  .weather-metrics {
    grid-template-columns: repeat(4, 1fr);
  }
}

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

  .header {
    margin-bottom: var(--spacing-xl);
  }

  .search-form {
    flex-direction: column;
  }

  .search-form__button {
    padding: var(--spacing-md);
  }

  .current-weather {
    padding: var(--spacing-lg);
    min-height: 240px;
  }

  .current-weather__temp {
    font-size: 3rem;
  }

  .weather-metrics {
    grid-template-columns: 1fr 1fr;
  }

  .daily-forecast__list {
    flex-wrap: wrap;
    justify-content: center;
  }

  .units-dropdown__content {
    right: auto;
    left: 0;
    min-width: 200px;
  }
}

@media (max-width: 480px) {
  .header {
    flex-direction: column;
    gap: var(--spacing-md);
    align-items: stretch;
  }

  .units-dropdown {
    align-self: flex-end;
  }

  .current-weather__main {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--spacing-md);
  }

  .current-weather__temp {
    font-size: 2.5rem;
  }

  .daily-forecast__list {
    gap: var(--spacing-xs);
  }

  .daily-forecast__item {
    min-width: 0;
    flex: 1;
  }

  .weather-metrics {
    grid-template-columns: 1fr;
  }
}

/* Loading States */
.loading {
  opacity: 0.6;
  pointer-events: none;
  position: relative;
}

.loading::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 40px;
  height: 40px;
  margin: -20px 0 0 -20px;
  border: 3px solid var(--neutral-600);
  border-top: 3px solid var(--blue-500);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  z-index: 1000;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Error States */
.error {
  color: var(--orange-500);
  background: var(--neutral-800);
  border: 1px solid var(--orange-500);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  margin: var(--spacing-md) 0;
  text-align: center;
  font-weight: 500;
  animation: fadeIn 0.3s ease-in;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Enhanced search form states */
.search-form__input:invalid {
  border: 2px solid var(--orange-500);
}

.search-form__button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* Weather data transition */
.current-weather,
.weather-metrics,
.daily-forecast,
.hourly-forecast {
  transition: opacity 0.3s ease;
}

/* Focus visible for better accessibility */
@media (prefers-reduced-motion: no-preference) {
  * {
    scroll-behavior: smooth;
  }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  :root {
    --neutral-800: hsl(243, 27%, 15%);
    --neutral-700: hsl(243, 23%, 18%);
  }
}

/* Reduced motion preferences */
@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;
  }
}