/* Custom Variables & Color Palette */
:root {
  --clr-primary-orange: hsl(25, 97%, 53%);
  --clr-neutral-white: hsl(0, 100%, 100%);
  --clr-neutral-grey-500: hsl(217, 12%, 75%);
  --clr-neutral-grey-900: hsl(213, 19%, 18%);
  --clr-neutral-grey-950: hsl(216, 12%, 8%);
  
  /* Additional dark gradient values based on visual spec */
  --clr-card-bg: radial-gradient(circle at top, hsl(213, 19%, 18%) 0%, hsl(216, 12%, 8%) 100%);
  --clr-circle-bg: hsl(213, 19%, 22%);

  --ff-primary: 'Overpass', sans-serif;
  --fs-body: 0.9375rem; /* 15px */
  --fw-regular: 400;
  --fw-bold: 700;
}

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

body {
  font-family: var(--ff-primary);
  font-size: var(--fs-body);
  background-color: var(--clr-neutral-grey-950);
  color: var(--clr-neutral-white);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 1.5rem;
}

/* Screen reader utility helper */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

/* App Container and Card Component Blocks (BEM Layout Engine) */
.app-container {
  width: 100%;
  max-width: 412px;
  display: flex;
  justify-content: center;
}

.card {
  background: var(--clr-card-bg);
  background-color: var(--clr-neutral-grey-900); /* Fallback */
  border-radius: 1.875rem;
  padding: 1.5rem;
  width: 100%;
}

@media (min-width: 576px) {
  .card {
    padding: 2rem 2.25rem;
  }
}

/* Card Element Views */
.card__view--hidden {
  display: none !important;
}

.card__view--thank-you {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 0.625rem 0;
}

/* UI Elements inside layout framework */
.card__icon-wrapper {
  background-color: var(--clr-circle-bg);
  width: 2.75rem;
  height: 2.75rem;
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  margin-bottom: 1.5rem;
}

.card__title {
  font-size: 1.5rem;
  font-weight: var(--fw-bold);
  margin-bottom: 0.75rem;
}

.card__title--center {
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

.card__description {
  color: var(--clr-neutral-grey-500);
  line-height: 1.5;
  font-size: 0.875rem;
  margin-bottom: 1.5rem;
}

@media (min-width: 576px) {
  .card__title { font-size: 1.75rem; }
  .card__description { font-size: 0.9375rem; }
}

.card__fieldset {
  border: none;
  margin-bottom: 1.5rem;
}

.card__ratings {
  display: flex;
  justify-content: space-between;
  gap: 0.5rem;
}

/* Custom Interactive Radio Component Structuring */
.card__rating-label {
  position: relative;
  flex: 1;
  max-width: 3.125rem;
  aspect-ratio: 1;
}

.card__rating-input {
  position: absolute;
  opacity: 0;
  width: 100%;
  height: 100%;
  cursor: pointer;
}

.card__rating-button {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  background-color: var(--clr-circle-bg);
  color: var(--clr-neutral-grey-500);
  display: flex;
  justify-content: center;
  align-items: center;
  font-weight: var(--fw-bold);
  transition: background-color 0.2s ease, color 0.2s ease;
}

/* Hover/Focus states for Ratings Input items */
.card__rating-input:hover + .card__rating-button {
  background-color: var(--clr-neutral-grey-500);
  color: var(--clr-neutral-white);
}

.card__rating-input:checked + .card__rating-button {
  background-color: var(--clr-primary-orange);
  color: var(--clr-neutral-white);
}

.card__rating-input:focus-visible + .card__rating-button {
  outline: 2px solid var(--clr-neutral-white);
  outline-offset: 3px;
}

/* Interactive Action Buttons styling rules */
.card__submit-btn {
  width: 100%;
  background-color: var(--clr-primary-orange);
  color: var(--clr-neutral-white);
  border: none;
  border-radius: 1.375rem;
  padding: 0.875rem;
  text-transform: uppercase;
  font-weight: var(--fw-bold);
  letter-spacing: 2px;
  cursor: pointer;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.card__submit-btn:hover {
  background-color: var(--clr-neutral-white);
  color: var(--clr-primary-orange);
}

.card__submit-btn:focus-visible {
  outline: 2px solid var(--clr-primary-orange);
  outline-offset: 3px;
}

/* Thank You badge configuration rendering specs */
.card__badge {
  background-color: var(--clr-circle-bg);
  padding: 0.375rem 1rem;
  border-radius: 1.375rem;
  margin-top: 1.5rem;
}

.card__badge-text {
  color: var(--clr-primary-orange);
  font-size: 0.875rem;
  line-height: 1.4;
}

/* Footer Attribution styling rules */
.attribution { 
  font-size: 0.6875rem; 
  text-align: center; 
  margin-top: 2rem;
  color: var(--clr-neutral-grey-500);
}
.attribution a { color: hsl(228, 45%, 54%); text-decoration: none; }
.attribution a:hover { text-decoration: underline; }