.student-challenges {
  background: #f5f6ee;
  color: #193d38;
  padding: 20px;
  border-radius: 16px;
  margin: 18px 0;
  text-align: left;
}
.student-challenges h3 {
  margin: 18px 0 10px;
  color: #193d38;
  font-size: 1.15rem;
}
.student-challenges h4 {
  margin: 0 0 8px;
}
.student-challenges p {
  font-size: 0.88rem;
  line-height: 1.55;
  margin: 8px 0;
  color: #385b54;
}
.student-challenges label {
  display: block;
  color: #193d38;
  font-weight: 600;
  margin: 10px 0 5px;
}
.student-challenges select,
.student-challenges textarea {
  box-sizing: border-box;
  width: 100%;
  background: #fffef9;
  color: #193d38;
  font: inherit;
  padding: 10px;
  border: 1px solid #64837a;
  border-radius: 8px;
}
.student-challenges textarea {
  min-height: 85px;
}
.student-challenges button {
  border: 1px solid #176354;
  background: #176354;
  color: #fff;
  font: inherit;
  font-size: 0.85rem;
  padding: 10px 12px;
  border-radius: 8px;
  margin: 5px 5px 5px 0;
  cursor: pointer;
}
.student-challenges button:disabled {
  opacity: 0.55;
  cursor: default;
}
.student-challenges :focus-visible {
  outline: 3px solid #9d660b;
  outline-offset: 3px;
}
.student-challenges a {
  color: #145b4e;
  display: inline-block;
  margin: 10px;
}
.challenge-choices,
.challenge-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.challenge-card {
  flex: 1 1 150px;
  padding: 16px;
  background: #fffef9;
  border: 1px solid #c2d0bf;
  border-radius: 10px;
}
.challenge-card progress {
  width: 100%;
  accent-color: #176354;
}
.challenge-best,
.challenge-notice,
.challenge-team {
  border: 1px solid #c2d0bf;
  border-left: 3px solid #8a691a;
  padding: 12px;
  margin: 10px 0;
  background: #fffef9;
  border-radius: 6px;
}
.challenge-best {
  animation: best-arrive 0.3s ease-out;
}
@keyframes best-arrive {
  from {
    opacity: 0;
    transform: translateY(5px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}
@media (prefers-reduced-motion: reduce) {
  .challenge-best {
    animation: none;
  }
}
.student-activity-notice {
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 10000;
  max-width: min(340px, calc(100vw - 40px));
  box-sizing: border-box;
  padding: 18px;
  border: 1px solid #b3c8bb;
  border-left: 4px solid #866820;
  background: #fffef9;
  color: #193d38;
  border-radius: 10px;
  box-shadow: 0 8px 24px #102c2b22;
  font:
    14px/1.5 system-ui,
    sans-serif;
}
.student-activity-notice a {
  color: #145b4e;
  margin-right: 15px;
}
.student-activity-notice button {
  padding: 8px 12px;
  border: 1px solid #315e51;
  color: #193d38;
  background: #fffef9;
  border-radius: 6px;
}
.student-challenges .challenge-card-face {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px;
  margin: -12px -12px 14px;
  border-radius: 9px 9px 0 0;
  background: repeating-linear-gradient(
    135deg,
    #e4ebe4,
    #e4ebe4 12px,
    #dce5db 12px,
    #dce5db 13px
  );
  color: #466250;
  font-size: 2.6rem;
  font-weight: 800;
  letter-spacing: -0.04em;
}
.student-challenges .challenge-card-face span {
  font-size: 0.65rem;
  letter-spacing: 0.15em;
  writing-mode: vertical-rl;
}
.student-challenges .is-collected .challenge-card-face {
  background: repeating-linear-gradient(
    135deg,
    #235b4c,
    #235b4c 12px,
    #306957 12px,
    #306957 13px
  );
  color: #fff;
}
.student-challenges .challenge-card:nth-child(2) .challenge-card-face {
  filter: hue-rotate(45deg);
}
.student-challenges .challenge-card:nth-child(3) .challenge-card-face {
  filter: hue-rotate(210deg);
}
.challenge-collection {
  margin: 14px 0;
  padding: 12px 0;
  border-top: 1px solid #c2d0bf;
  border-bottom: 1px solid #c2d0bf;
}
.challenge-collection summary {
  cursor: pointer;
  font-weight: 700;
  padding: 8px 0;
}
.challenge-notice {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  padding: 8px 12px;
}
.challenge-notice p:empty {
  display: none;
}
.challenge-notice button {
  margin-left: auto;
  background: transparent;
  color: #176354;
  padding: 6px 10px;
}