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

:root {
  --color-white: hsl(0, 100%, 100%);
  --color-purple-100: hsl(275, 100%, 97%);
  --color-purple-600: hsl(292, 16%, 49%);
  --color-purple-950: hsl(292, 42%, 14%);

  --font-family: 'Work Sans', sans-serif;
  --font-size-body: 1rem;        /* 16px */
  --font-size-question: 1rem;
  --font-size-title: 2rem;

  --transition-speed: 300ms;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-body);
  background-color: var(--color-purple-100);
  background-image: url('./assets/images/background-pattern-mobile.svg');
  background-repeat: no-repeat;
  background-position: top center;
  background-size: 100% auto;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
}

main {
  width: 100%;
  display: flex;
  justify-content: center;
  flex: 1;
  align-items: center;
}

/* ===========================
   Card
   =========================== */
.card {
  background-color: var(--color-white);
  border-radius: 1rem;
  width: 100%;
  max-width: 37.5rem;
}

.card__content {
  position: relative;
  z-index: 1;
  padding: 2.5rem 1.5rem;
}

.card__header {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.card__star {
  width: 2.5rem;
  height: 2.5rem;
  flex-shrink: 0;
}

.card__title {
  font-size: var(--font-size-title);
  font-weight: 700;
  color: var(--color-purple-950);
  line-height: 1;
}

/* ===========================
   Accordion
   =========================== */
.accordion {
  list-style: none;
}

.accordion__item {
  border-bottom: 1px solid var(--color-purple-100);
  padding: 1.25rem 0;
}

.accordion__item:first-child {
  padding-top: 0;
}

.accordion__item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

/* Trigger button */
.accordion__trigger {
  width: 100%;
  background: none;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  text-align: left;
  color: var(--color-purple-950);
  font-family: var(--font-family);
  font-size: var(--font-size-question);
  font-weight: 600;
  padding: 0;
  line-height: 1.4;
  transition: color var(--transition-speed) ease;
  border-radius: 0.25rem;
}

.accordion__trigger:hover,
.accordion__trigger:focus-visible {
  color: hsl(292, 100%, 40%);
}

.accordion__trigger:focus-visible {
  outline: 3px solid hsl(292, 100%, 40%);
  outline-offset: 4px;
}

.accordion__icon {
  flex-shrink: 0;
  width: 1.875rem;
  height: 1.875rem;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.accordion__icon img {
  position: absolute;
  width: 100%;
  height: 100%;
  transition: opacity var(--transition-speed) ease, transform var(--transition-speed) ease;
}

.icon-plus  { opacity: 1; }
.icon-minus { opacity: 0; }

.accordion__trigger[aria-expanded="true"] .icon-plus  { opacity: 0; }
.accordion__trigger[aria-expanded="true"] .icon-minus { opacity: 1; }

.accordion__panel {
  overflow: hidden;
}

.accordion__panel[hidden] {
  display: none;
}

.accordion__panel p {
  color: var(--color-purple-600);
  line-height: 1.6;
  padding-top: 1.25rem;
}

@media (min-width: 600px) {
  body {
    background-image: url('./assets/images/background-pattern-desktop.svg');
    background-size: 100% auto;
  }

  .card {
    max-width: 40rem;
  }

  .card__content {
    padding: 2.5rem;
  }

  .card__title {
    font-size: 3.5rem;
  }

  :root {
    --font-size-question: 1.125rem;
  }

  .card__star {
    width: 2.75rem;
    height: 2.75rem;
  }
}

.attribution {
  font-size: 0.6875rem;
  text-align: center;
  padding: 1rem 0 0.5rem;
  color: var(--color-purple-600);
}

.attribution a {
  color: hsl(228, 45%, 44%);
  text-underline-offset: 2px;
}

.attribution a:focus-visible {
  outline: 2px solid hsl(228, 45%, 44%);
  outline-offset: 3px;
  border-radius: 2px;
}