/* ===== INFINITE STAIRS (무한의 계단) CSS ===== */

#stairsGame {
  padding: 0;
  gap: 0;
  background: #0d1b2a;
  overflow: hidden;
  position: relative;
  user-select: none;
  -webkit-user-select: none;
}

/* ===== HUD ===== */
.st-hud {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding: 48px 16px 8px;
  z-index: 10;
  position: relative;
}

.st-hud .back-btn {
  background: rgba(255,255,255,0.08) !important;
  border: 1px solid rgba(255,255,255,0.1) !important;
  border-radius: 10px !important;
  color: rgba(255,255,255,0.6) !important;
  width: 36px !important;
  height: 36px !important;
  display: flex !important;
  align-items: center !important;
  justify-content: center !important;
  font-size: 16px !important;
  padding: 0 !important;
}

.st-score-box {
  text-align: left;
}

.st-score-label {
  font-size: 9px;
  text-transform: uppercase;
  letter-spacing: 2px;
  color: rgba(255,255,255,0.35);
  font-family: 'Oswald', sans-serif;
}

.st-score-value {
  font-family: 'Oswald', sans-serif;
  font-size: 28px;
  font-weight: 700;
  color: #fff;
  line-height: 1;
}

.st-hud-right {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 6px;
}

.st-combo {
  background: rgba(253,114,114,0.2);
  border: 1px solid rgba(253,114,114,0.4);
  color: #fd7272;
  font-family: 'Oswald', sans-serif;
  font-size: 13px;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 100px;
  display: none;
}

.st-step-display {
  font-size: 11px;
  color: rgba(255,255,255,0.3);
  font-family: 'Oswald', sans-serif;
  letter-spacing: 1px;
}

/* ===== Stamina Bar ===== */
.st-stamina-wrap {
  padding: 0 16px;
  margin-bottom: 6px;
  z-index: 10;
  position: relative;
}

.st-stamina-outer {
  width: 100%;
  height: 6px;
  background: rgba(255,255,255,0.08);
  border-radius: 3px;
  overflow: hidden;
}

.st-stamina-fill {
  height: 100%;
  border-radius: 3px;
  width: 100%;
  background: linear-gradient(90deg, #55efc4, #00b894);
  box-shadow: 0 0 12px rgba(85,239,196,0.4);
  transition: width 0.1s linear;
}

.st-stamina-fill.warn {
  background: linear-gradient(90deg, #ffeaa7, #fdcb6e);
  box-shadow: 0 0 12px rgba(255,234,167,0.4);
}

.st-stamina-fill.danger {
  background: linear-gradient(90deg, #fd7272, #e17055);
  box-shadow: 0 0 12px rgba(253,114,114,0.4);
  animation: st-stamina-pulse 0.8s ease-in-out infinite;
}

@keyframes st-stamina-pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.6; }
}

.st-stamina-info {
  display: flex;
  justify-content: space-between;
  font-size: 9px;
  color: rgba(255,255,255,0.3);
  margin-top: 2px;
  font-family: 'Oswald', sans-serif;
  letter-spacing: 1px;
  text-transform: uppercase;
}

/* ===== Canvas Area ===== */
.st-canvas-wrap {
  flex: 1;
  position: relative;
  overflow: hidden;
  min-height: 0;
}

.st-canvas-wrap canvas {
  display: block;
  width: 100%;
  height: 100%;
}

/* Vignette overlay for low stamina */
.st-vignette {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 5;
  opacity: 0;
  background: radial-gradient(ellipse at center, transparent 50%, rgba(253,60,60,0.4) 100%);
  transition: opacity 0.3s;
}

/* ===== Controls ===== */
.st-controls {
  display: flex;
  gap: 12px;
  padding: 12px 16px 36px;
  z-index: 10;
  position: relative;
}

.st-btn {
  flex: 1;
  height: 72px;
  border-radius: 20px;
  border: none;
  font-family: 'Black Han Sans', sans-serif;
  font-size: 16px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  position: relative;
  overflow: hidden;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  transition: transform 0.1s;
}

.st-btn:active {
  transform: scale(0.96);
}

.st-btn-left {
  background: linear-gradient(135deg, rgba(253,114,114,0.2), rgba(253,114,114,0.1));
  border: 1.5px solid rgba(253,114,114,0.35);
  color: #fd7272;
}

.st-btn-right {
  background: linear-gradient(135deg, rgba(85,239,196,0.2), rgba(85,239,196,0.1));
  border: 1.5px solid rgba(85,239,196,0.35);
  color: #55efc4;
}

.st-btn-arrow {
  font-size: 22px;
}

.st-btn-sub {
  font-size: 9px;
  opacity: 0.5;
  position: absolute;
  bottom: 8px;
  letter-spacing: 1px;
  font-family: 'Oswald', sans-serif;
}

/* ===== Countdown Overlay ===== */
.st-countdown-overlay {
  position: absolute;
  inset: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.6);
  backdrop-filter: blur(4px);
}

.st-countdown-num {
  font-family: 'Oswald', sans-serif;
  font-size: 120px;
  font-weight: 700;
  color: #fff;
  text-shadow: 0 0 60px rgba(108,92,231,0.6);
  animation: st-countdown-pop 1s ease-in-out infinite;
}

.st-countdown-num.go {
  font-size: 80px;
  color: #55efc4;
  text-shadow: 0 0 60px rgba(85,239,196,0.6);
}

@keyframes st-countdown-pop {
  0% { transform: scale(1.2); opacity: 0.5; }
  50% { transform: scale(1); opacity: 1; }
  100% { transform: scale(0.9); opacity: 0.5; }
}

/* ===== Death Overlay ===== */
.st-death-overlay {
  position: absolute;
  inset: 0;
  z-index: 60;
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.75);
  backdrop-filter: blur(6px);
  padding: 40px 30px;
}

.st-death-title {
  font-family: 'Oswald', sans-serif;
  font-size: 36px;
  font-weight: 700;
  color: #fd7272;
  margin-bottom: 8px;
  text-shadow: 0 0 30px rgba(253,114,114,0.4);
}

.st-death-reason {
  font-size: 14px;
  color: rgba(255,255,255,0.4);
  margin-bottom: 32px;
}

.st-death-score-box {
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 20px;
  padding: 20px 48px;
  text-align: center;
  margin-bottom: 12px;
}

.st-death-score {
  font-family: 'Oswald', sans-serif;
  font-size: 52px;
  font-weight: 700;
  color: #fff;
  line-height: 1;
}

.st-death-score-label {
  font-size: 10px;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: rgba(255,255,255,0.3);
  margin-top: 4px;
}

.st-death-stats {
  display: flex;
  gap: 24px;
  margin-bottom: 32px;
}

.st-death-stat {
  text-align: center;
}

.st-death-stat-val {
  font-family: 'Oswald', sans-serif;
  font-size: 20px;
  font-weight: 700;
  color: #a29bfe;
}

.st-death-stat-label {
  font-size: 9px;
  color: rgba(255,255,255,0.3);
  letter-spacing: 1px;
  text-transform: uppercase;
}

.st-death-waiting {
  font-size: 13px;
  color: rgba(255,255,255,0.4);
  margin-top: 12px;
}

/* ===== Results Overlay ===== */
.st-results-overlay {
  position: absolute;
  inset: 0;
  z-index: 70;
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.85);
  backdrop-filter: blur(8px);
  padding: 40px 20px;
}

.st-results-title {
  font-family: 'Oswald', sans-serif;
  font-size: 28px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 24px;
  text-shadow: 0 0 20px rgba(108,92,231,0.4);
}

.st-results-list {
  width: 100%;
  max-width: 340px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 24px;
}

.st-rank-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px;
  background: rgba(255,255,255,0.06);
  border-left: 4px solid #a29bfe;
  border-radius: 0 8px 8px 0;
  animation: slideIn 0.3s ease;
}

.st-rank-item.st-rank-me {
  background: rgba(108,92,231,0.15);
  border-left-color: #6c5ce7;
}

.st-rank-pos {
  font-family: 'Oswald', sans-serif;
  font-size: 18px;
  font-weight: 700;
  color: #a29bfe;
  min-width: 32px;
  text-align: center;
}

.st-rank-avatar {
  font-size: 20px;
}

.st-rank-name {
  flex: 1;
  font-weight: 700;
  font-size: 14px;
  color: #fff;
}

.st-rank-score {
  font-family: 'Oswald', sans-serif;
  font-size: 14px;
  color: rgba(255,255,255,0.7);
}

.st-results-btn {
  max-width: 280px;
  width: 100%;
}

/* ===== Players Bar (multiplayer) ===== */
.st-players-bar {
  display: flex;
  justify-content: center;
  gap: 8px;
  padding: 4px 16px;
  z-index: 10;
  position: relative;
}

.st-player-pip {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  font-size: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255,255,255,0.08);
  border: 1.5px solid rgba(255,255,255,0.15);
  transition: all 0.3s;
}

.st-player-pip.alive {
  border-color: rgba(85,239,196,0.4);
}

.st-player-pip.dead {
  opacity: 0.3;
  filter: grayscale(1);
}

.st-player-pip.me {
  border-color: rgba(108,92,231,0.6);
  box-shadow: 0 0 8px rgba(108,92,231,0.3);
}

@keyframes slideIn {
  from { opacity: 0; transform: translateX(-10px); }
  to { opacity: 1; transform: translateX(0); }
}

/* ===== Canvas touch hint ===== */
.st-canvas-wrap {
  cursor: pointer;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

/* ===== Mobile: bigger touch targets ===== */
@media (max-width: 430px) {
  .st-btn {
    height: 64px;
    font-size: 15px;
    border-radius: 16px;
  }
  .st-btn-arrow { font-size: 20px; }
  .st-controls { gap: 10px; padding: 10px 12px 28px; }
  .st-hud { padding: 40px 12px 6px; }
}

@media (max-width: 360px) {
  .st-btn {
    height: 56px;
    font-size: 14px;
    border-radius: 14px;
  }
  .st-btn-arrow { font-size: 18px; }
  .st-controls { gap: 8px; padding: 8px 10px 24px; }
  .st-hud { padding: 36px 10px 4px; }
  .st-score-value { font-size: 20px; }
}

@media (max-height: 600px) {
  .st-btn { height: 50px; font-size: 13px; }
  .st-controls { padding: 6px 10px 16px; }
  .st-hud { padding: 28px 10px 4px; }
}