.challenge-page {
  background: var(--bg-radial);
}

.challenge-page main > section {
  padding: 1.75rem 0;
}

.challenge-hero {
  background: var(--gradient-blue);
  color: var(--text-on-blue);
  display: flex;
  align-items: flex-start;
  padding-top: 0;
  padding-bottom: 0.2rem;
}

.challenge-hero-inner {
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 clamp(16px, 3vw, 28px) 0.2rem;
  text-align: center;
}

.challenge-eyebrow {
  margin: 0 0 0.2rem;
  font-size: 0.82rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.82);
}

.challenge-hero h1 {
  margin: 0;
  color: #ffffff;
  font-size: clamp(2rem, 4vw, 3rem);
  line-height: 1.02;
}

.challenge-lead {
  max-width: 700px;
  margin: 0.3rem auto 0;
  color: rgba(255, 255, 255, 0.92);
  font-size: clamp(0.98rem, 1.4vw, 1.08rem);
}

.challenge-hero-actions {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.9rem;
  margin-top: 0.55rem;
}

.challenge-primary-link,
.challenge-secondary-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0.8rem 1.2rem;
  border-radius: 999px;
  font-weight: 700;
  text-align: center;
}

.challenge-primary-link {
  background: #ffffff;
  color: var(--main-blue-strong);
  box-shadow: 0 18px 40px rgba(4, 33, 52, 0.16);
}

.challenge-secondary-link {
  border: 1px solid rgba(255, 255, 255, 0.32);
  color: #ffffff;
  background: rgba(255, 255, 255, 0.08);
}

.challenge-primary-link:hover,
.challenge-primary-link:focus,
.challenge-secondary-link:hover,
.challenge-secondary-link:focus {
  text-decoration: none;
}

.challenge-intro,
.challenge-close {
  max-width: 960px;
}

.challenge-intro {
  padding-top: 1rem;
  padding-bottom: 0.4rem;
}

.challenge-card {
  text-align: center;
}

.challenge-card p + p {
  margin-top: 0.9rem;
}

.challenge-card h2,
.challenge-days-heading h2 {
  margin: 0 0 1rem;
  color: var(--main-blue-strong);
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  line-height: 1.12;
}

.challenge-card p,
.challenge-days-heading p,
.challenge-day-card p {
  margin: 0;
  color: rgba(7, 61, 88, 0.88);
}

.challenge-intro-closing {
  font-weight: 700;
  color: var(--main-blue-strong);
}

.challenge-print,
.challenge-close {
  max-width: 960px;
}

.challenge-print {
  padding-top: 0.2rem;
  padding-bottom: 0.4rem;
}

.challenge-rules {
  padding-top: 0.35rem;
  padding-bottom: 0.4rem;
}

.challenge-rules-inner {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
}

.challenge-rule-card {
  padding: 1.1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  background: var(--surface-soft);
  box-shadow: var(--shadow-soft);
}

.challenge-rule-card h2 {
  margin: 0 0 0.9rem;
  color: var(--main-blue-strong);
  font-size: 1.35rem;
  line-height: 1.2;
}

.challenge-rule-card p {
  margin: 0;
  color: rgba(7, 61, 88, 0.88);
}

.challenge-rule-card p + p {
  margin-top: 0.75rem;
}

.challenge-mini-eyebrow {
  margin: 0 0 0.75rem;
  color: var(--main-blue-strong);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.challenge-days {
  padding-top: 0.4rem;
  padding-bottom: 0.8rem;
}

.challenge-days-heading {
  max-width: 720px;
  margin: 0 auto 1rem;
  text-align: center;
}

.challenge-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  align-items: stretch;
}

.challenge-day-card {
  position: relative;
  display: block;
  width: 100%;
  padding: 0;
  border: none;
  background: transparent;
  cursor: pointer;
  perspective: 1200px;
  text-align: left;
  font: inherit;
  color: inherit;
}

.challenge-day-card-inner {
  position: relative;
  display: grid;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transition: transform 0.7s ease;
}

.challenge-day-card[aria-expanded='true'] .challenge-day-card-inner {
  transform: rotateY(180deg);
}

.challenge-day-face {
  grid-area: 1 / 1;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  align-items: center;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  background: var(--surface-soft);
  box-shadow: var(--shadow-soft);
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  text-align: center;
}

.challenge-day-face-front {
  justify-content: flex-start;
}

.challenge-day-face-back {
  transform: rotateY(180deg);
}

.challenge-day-face-front .challenge-day-number {
  align-self: center;
}

.challenge-day-face-front h3 {
  width: 100%;
  margin-bottom: 0;
}

.challenge-card-center {
  display: flex;
  flex: 1;
  width: 100%;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.35rem;
}

.challenge-day-card:hover .challenge-day-face,
.challenge-day-card:focus-visible .challenge-day-face {
  border-color: rgba(31, 180, 230, 0.5);
}

.challenge-day-card:focus-visible {
  outline: none;
}

.challenge-reveal-hint {
  display: flex;
  align-self: center;
  margin-top: 0;
  padding: 0.45rem 0.8rem;
  border-radius: 999px;
  background: rgba(31, 180, 230, 0.14);
  color: var(--main-blue-strong);
  font-size: 0.88rem;
  font-weight: 700;
}

.challenge-card-isotype {
  display: block;
  width: 82px;
  height: auto;
  margin-bottom: 0;
}

.challenge-day-number {
  display: inline-flex;
  margin-bottom: 0.9rem;
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  background: rgba(31, 180, 230, 0.14);
  color: var(--main-blue-strong);
  font-size: 0.84rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.challenge-day-card h3 {
  margin: 0 0 0.6rem;
  color: var(--main-blue-strong);
  font-size: 1.2rem;
  line-height: 1.2;
}

.challenge-day-card p + p {
  margin-top: 0.65rem;
}

.challenge-list {
  margin: 0.9rem 0;
  padding-left: 0;
  list-style-position: inside;
  color: rgba(7, 61, 88, 0.88);
}

.challenge-list li + li {
  margin-top: 0.4rem;
}

.challenge-quote {
  font-weight: 700;
  color: var(--main-blue-strong);
  font-size: 1.05rem;
}

.challenge-card-accent {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.96) 0%, rgba(239, 248, 255, 0.96) 100%);
}

.challenge-card-accent .challenge-primary-link {
  margin-top: 1.5rem;
  background: var(--main-blue-strong);
  color: #ffffff;
  box-shadow: none;
}

@media (max-width: 640px) {
  .challenge-hero {
    padding-top: 0;
    padding-bottom: 0.15rem;
  }

  .challenge-hero-inner {
    padding-top: 0;
    padding-bottom: 0.15rem;
  }

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