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

html, body {
  height: 100%;
}

.mute-btn {
  position: fixed;
  top: 10px;
  right: 10px;
  z-index: 999;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(6px);
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #374151;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.18);
  transition: background 0.15s, transform 0.1s;
}
.mute-btn:hover { background: rgba(255, 255, 255, 1); transform: scale(1.08); }
.mute-btn:active { transform: scale(0.95); }

body {
  min-height: 100%;
  background-color: var(--start-bg-color, #9c3b00);
  background-image: var(--start-bg-image, none);
  background-size: contain;
  background-position: center;
  background-repeat: repeat;
}

a {
  text-decoration: none;
  color: #333;
}

.stage-select-section {
  min-height: 100vh;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  padding: 2.4vh 0;
}

.back-button-wrap {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--border-color, #e68600);
  color: #fff;
  font-weight: 700;
  font-size: 15px;
  padding: 10px 28px;
  border-radius: 999px;
  margin-bottom: 20px;
  cursor: pointer;
}

.back-button-img-wrap {
  display: block;
  margin: 0 auto 2vh;
  flex-shrink: 0;
}

.back-button-img-wrap img {
  display: block;
  height: 6vh;
  width: auto;
  max-width: calc(100vw - 32px);
  cursor: pointer;
  border: solid 0.7vh var(--border-color, #e68600);
  border-radius: 1.7vh;
}

.stage-card {
  position: relative;
  display: block;
  width: fit-content;
  height: auto;
  flex-shrink: 0;
  max-width: calc(100vw - 32px);
  margin: 0 auto 2vh;
  background: #fff;
  border: solid 0.7vh var(--border-color, #e68600);
  border-radius: 1.7vh;
  overflow: hidden;
  text-align: center;
}

.stage-card.is-locked {
  opacity: .5;
  cursor: not-allowed;
  pointer-events: none;
}

.stage-card img {
  display: block;
  width: auto;
  max-width: 100%;
  height: 17vh;
  object-fit: contain;
}

.stage-card--intro img {
  height: 26.5vh;
}

.stage-card-default {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 20px;
  gap: 6px;
  font-size: 15px;
  font-weight: 700;
  color: #333;
}

.stage-num {
  font-size: 12px;
  color: var(--border-color, #e68600);
  font-weight: 600;
}

.stage-badge-wrap {
  position: absolute;
  right: 0.8vh;
  bottom: 0.8vh;
  z-index: 2;
  margin: 0;
  line-height: 1;
}

.stage-card img.stage-clear-band {
  position: absolute;
  right: -1.8vh;
  bottom: -3.5vh;
  z-index: 2;
  width: 17vh;
  height: 17vh;
  max-width: none;
  pointer-events: none;
}

.stage-badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  padding: 2px 12px;
  border-radius: 20px;
}

.stage-badge--cleared {
  background: #10b981;
  color: #fff;
}
.stage-badge--progress {
  background: #f59e0b;
  color: #fff;
}