/* ==========================================================================
   CSS CUSTOM DESIGN PROPERTIES
   ========================================================================== */
:root {
  --color-green-200: hsl(148, 38%, 91%);
  --color-green-500: hsl(169, 82%, 35%);
  --color-green-600: hsl(169, 82%, 27%);
  --color-red: hsl(0, 66%, 54%);
  --color-neutral-400: hsl(186, 15%, 59%);
  --color-neutral-900: hsl(187, 24%, 22%);
  --color-white: hsl(0, 0%, 100%);
  
  --font-family: 'Karla', sans-serif;
  
  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 1.5rem;
  --space-lg: 2.5rem;
}

/* ==========================================================================
   GLOBAL STRUCTURE RESET STRATEGY
   ========================================================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-family);
  background-color: var(--color-green-200);
  color: var(--color-neutral-900);
  font-size: 1rem;
  line-height: 1.5;
  min-block-size: 100vh;
  display: grid;
  place-items: center;
  padding: var(--space-md) var(--space-sm);
}

/* ==========================================================================
   FORM CONTAINER LAYOUT WRAPPERS
   ========================================================================== */
.main-container {
  width: 100%;
  max-inline-size: 730px;
}

.card {
  background-color: var(--color-white);
  padding: var(--space-md);
  border-radius: 1rem;
}

@media (min-width: 600px) {
  .card {
    padding: var(--space-lg);
  }
}

.card__title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-neutral-900);
  margin-block-end: var(--space-md);
  letter-spacing: -1px;
}

/* ==========================================================================
   BEM FORM SYSTEM ARCHITECTURE
   ========================================================================== */
.form {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.form__row {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

@media (min-width: 600px) {
  .form__row--split {
    flex-direction: row;
    gap: var(--space-md);
  }
  .form__row--split > * {
    flex: 1;
  }
}

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

.form__fieldset {
  border: none;
}

.form__label {
  font-size: 1rem;
  font-weight: 400;
  color: var(--color-neutral-900);
}

.form__required {
  color: var(--color-green-600);
  margin-inline-start: 0.25rem;
}

/* Field Input Components */
.form__input,
.form__textarea {
  font-family: inherit;
  font-size: 1.125rem;
  padding: 0.75rem 1.25rem;
  border: 1px solid var(--color-neutral-400);
  border-radius: 0.5rem;
  color: var(--color-neutral-900);
  outline: none;
  transition: border-color 0.15s, box-shadow 0.15s;
  width: 100%;
}

.form__textarea {
  min-block-size: 240px;
  resize: vertical;
}

@media (min-width: 600px) {
  .form__textarea {
    min-block-size: 105px;
  }
}

/* Hover Elements Interaction States */
.form__input:hover,
.form__textarea:hover,
.form__radio-wrapper:hover,
.form__checkbox-wrapper:hover {
  border-color: var(--color-green-600);
}

/* Focus States */
.form__input:focus,
.form__textarea:focus {
  border-color: var(--color-green-600);
}

/* Custom Interactive Box Wrap Layout Rules */
.form__radio-wrapper,
.form__checkbox-wrapper {
  display: flex;
  align-items: center;
  padding: 0.875rem 1.25rem;
  border: 1px solid var(--color-neutral-400);
  border-radius: 0.5rem;
  cursor: pointer;
  position: relative;
  transition: background-color 0.2s, border-color 0.2s;
}

/* Custom Checkbox Placement Tweak */
.form__checkbox-wrapper {
  border: none;
  padding: var(--space-xs) 0 0 0;
  align-items: flex-start;
}

/* Selected Element Active Wrap Highlight Classes */
.form__radio-wrapper--selected {
  background-color: var(--color-green-200);
  border-color: var(--color-green-600);
}

/* Accessible Native Element Hiding Pattern */
.form__radio,
.form__checkbox {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

/* Custom Checkbox/Radio Component Architecture */
.form__custom-radio {
  inline-size: 20px;
  block-size: 20px;
  border: 1px solid var(--color-neutral-400);
  border-radius: 50%;
  margin-inline-end: 0.875rem;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.form__radio:checked + .form__custom-radio {
  border-color: var(--color-green-600);
  background-image: url('./assets/images/icon-radio-selected.svg');
  background-repeat: no-repeat;
  background-position: center;
}

.form__custom-checkbox {
  inline-size: 18px;
  block-size: 18px;
  border: 1px solid var(--color-neutral-400);
  border-radius: 3px;
  margin-inline-end: 1rem;
  margin-block-start: 3px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.form__checkbox:checked + .form__custom-checkbox {
  border: none;
  background-image: url('./assets/images/icon-checkbox-check.svg');
  background-repeat: no-repeat;
  background-position: center;
}

/* Keyboard Navigation Focus Indicator Support Elements */
.form__radio:focus-visible + .form__custom-radio,
.form__checkbox:focus-visible + .form__custom-checkbox {
  outline: 2px solid var(--color-green-600);
  outline-offset: 4px;
}

/* Error Element Display Architecture Styles */
.form__group--error .form__input,
.form__group--error .form__textarea,
.form__group--error .form__radio-wrapper {
  border-color: var(--color-red);
}

.form__error-message {
  color: var(--color-red);
  font-size: 0.875rem;
  display: none;
}

.form__group--error > .form__error-message,
.form__fieldset.form__group--error .form__error-message {
  display: block;
}

/* ==========================================================================
   SUBMIT INTERACTIVE TRIGGER BUTTON
   ========================================================================== */
.form__submit-btn {
  background-color: var(--color-green-600);
  color: var(--color-white);
  border: none;
  font-family: inherit;
  font-size: 1.125rem;
  font-weight: 700;
  padding: 1rem;
  border-radius: 0.5rem;
  cursor: pointer;
  transition: background-color 0.15s;
  margin-block-start: var(--space-xs);
}

.form__submit-btn:hover,
.form__submit-btn:focus-visible {
  background-color: var(--color-neutral-900);
  outline: none;
}

/* ==========================================================================
   TOAST MODAL NOTIFICATION PATTERNS
   ========================================================================== */
.toast {
  position: fixed;
  top: 24px;
  left: 50%;
  transform: translateX(-50%);
  background-color: var(--color-neutral-900);
  color: var(--color-white);
  padding: var(--space-md);
  border-radius: 0.75rem;
  width: calc(100% - 32px);
  max-inline-size: 450px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
  z-index: 1000;
  transition: opacity 0.3s cubic-bezier(0.4, 0, 0.2, 1), transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.toast.hidden {
  opacity: 0;
  transform: translate(-50%, -40px);
  pointer-events: none;
}

.toast__header {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  margin-block-end: 0.5rem;
}

.toast__title {
  font-size: 1.125rem;
  font-weight: 700;
}

.toast__body {
  font-size: 0.875rem;
  color: var(--color-green-200);
}

/* ==========================================================================
   ATTRIBUTION FOOTER
   ========================================================================== */
.attribution {
  font-size: 0.75rem;
  text-align: center;
  margin-block-start: var(--space-md);
}
.attribution a {
  color: var(--color-green-600);
  text-decoration: none;
  font-weight: 700;
}
.attribution a:hover {
  text-decoration: underline;
}