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

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: linear-gradient(135deg, #0f0c29, #302b63, #24243e);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
}

.page-menu {
  background: linear-gradient(135deg, #0f0c29, #302b63, #24243e);
}

.page-menu .container {
  max-width: 740px;
}

[data-mode] .container {
  max-width: 700px;
}

.container {
  background: rgba(255, 255, 255, 0.07);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-radius: 24px;
  padding: 36px 32px;
  width: 100%;
  box-shadow: 0 25px 80px rgba(0, 0, 0, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.06);
}

header {
  text-align: center;
  margin-bottom: 24px;
}

header h1 {
  color: #fff;
  font-size: 2.2rem;
  font-weight: 800;
  letter-spacing: 1px;
}

.subtitle {
  color: rgba(255, 255, 255, 0.5);
  font-size: 0.95rem;
  margin-top: 4px;
}

.controls {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin-bottom: 28px;
}

.btn {
  padding: 10px 24px;
  border: none;
  border-radius: 12px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  user-select: none;
  text-decoration: none;
}

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

.btn-primary {
  background: linear-gradient(135deg, #667eea, #764ba2);
  color: #fff;
  box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.btn-primary:hover {
  box-shadow: 0 6px 25px rgba(102, 126, 234, 0.6);
  transform: translateY(-2px);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.08);
  color: rgba(255, 255, 255, 0.7);
  border: 1px solid rgba(255, 255, 255, 0.12);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.14);
  color: #fff;
  transform: translateY(-2px);
}

.btn-secondary:disabled {
  opacity: 0.3;
  cursor: not-allowed;
  transform: none;
}

.btn-challenge {
  background: linear-gradient(135deg, #ff9800, #f57c00);
  color: #fff;
  box-shadow: 0 4px 15px rgba(255, 152, 0, 0.35);
}

.btn-challenge:hover {
  box-shadow: 0 6px 25px rgba(255, 152, 0, 0.55);
  transform: translateY(-2px);
}

.cards {
  display: flex;
  justify-content: center;
  gap: 14px;
  flex-wrap: wrap;
  min-height: 162px;
  align-items: center;
  margin-bottom: 20px;
  perspective: 800px;
}

.card {
  width: 110px;
  height: 152px;
  background: linear-gradient(160deg, #ffffff, #f5f5f8);
  border-radius: 12px;
  border: 2px solid #d0d0d8;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.9);
  cursor: pointer;
  transition: all 0.2s ease;
  user-select: none;
  position: relative;
  overflow: hidden;
  font-family: 'Georgia', 'Times New Roman', serif;
  flex-shrink: 0;
}

.card:hover:not(.card-back):not(.card-disabled) {
  transform: translateY(-6px);
  box-shadow: 0 14px 35px rgba(0, 0, 0, 0.4);
}

.card:active:not(.card-back):not(.card-disabled) {
  transform: translateY(-2px) scale(0.97);
}

.card-corner {
  position: absolute;
  display: flex;
  flex-direction: column;
  align-items: center;
  line-height: 1.1;
}

.card-corner-top {
  top: 7px;
  left: 9px;
}

.card-corner-bottom {
  bottom: 7px;
  right: 9px;
  transform: rotate(180deg);
}

.corner-value {
  font-size: 0.85rem;
  font-weight: 700;
}

.corner-suit {
  font-size: 0.6rem;
  line-height: 1;
}

.card-center {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  line-height: 1;
}

.center-value {
  font-size: 2.4rem;
  font-weight: 800;
  letter-spacing: -1px;
}

.center-suit {
  font-size: 1.8rem;
  margin-top: 2px;
}

.suit-red {
  color: #d32f2f;
}

.suit-red .corner-suit,
.suit-red .center-suit {
  color: #d32f2f;
}

.suit-black {
  color: #1a1a2e;
}

.suit-black .corner-value,
.suit-black .center-value {
  color: #1a1a2e;
}

.card-back {
  background: linear-gradient(135deg, #1a237e, #283593);
  border: 2px solid rgba(255, 255, 255, 0.08);
  cursor: default;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.35);
}

.card-back:hover {
  transform: none;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.35);
}

.card-back:active {
  transform: none;
}

.card-back-inner {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 82%;
  height: 88%;
  border: 2px solid rgba(255, 255, 255, 0.05);
  border-radius: 8px;
  background: repeating-linear-gradient(
    45deg,
    transparent,
    transparent 4px,
    rgba(255, 255, 255, 0.02) 4px,
    rgba(255, 255, 255, 0.02) 8px
  );
}

.card-selected {
  border-color: #4a90d9;
  box-shadow: 0 0 35px rgba(74, 144, 217, 0.7), 0 0 60px rgba(74, 144, 217, 0.25), 0 8px 30px rgba(0, 0, 0, 0.35);
  transform: translateY(-6px);
}

.card-selected::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(105deg, transparent 20%, rgba(255, 255, 255, 0.5) 45%, rgba(255, 255, 255, 0.2) 50%, transparent 70%);
  pointer-events: none;
  border-radius: inherit;
  animation: cardShimmer 2s ease-in-out infinite;
}

.card-selected:hover {
  transform: translateY(-6px);
}

.card-disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

.card-won {
  border-color: #4caf50;
  box-shadow: 0 0 35px rgba(76, 175, 80, 0.5), 0 8px 30px rgba(0, 0, 0, 0.35);
}

.card-lost {
  border-color: #f44336;
  box-shadow: 0 0 30px rgba(244, 67, 54, 0.3), 0 8px 30px rgba(0, 0, 0, 0.35);
}

.operations {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin-bottom: 20px;
}

.op-btn {
  width: 62px;
  height: 62px;
  border-radius: 14px;
  border: 2px solid rgba(255, 255, 255, 0.08);
  font-size: 1.6rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.2s;
  background: rgba(255, 255, 255, 0.06);
  color: rgba(255, 255, 255, 0.7);
  user-select: none;
  display: flex;
  align-items: center;
  justify-content: center;
}

.op-btn:hover:not(:disabled) {
  background: rgba(255, 255, 255, 0.14);
  color: #fff;
  transform: scale(1.06);
}

.op-btn:active:not(:disabled) {
  transform: scale(0.94);
}

.op-btn:disabled {
  opacity: 0.25;
  cursor: not-allowed;
  transform: none;
}

.op-btn.active {
  background: #ff9800;
  border-color: #ff9800;
  color: #fff;
  box-shadow: 0 0 24px rgba(255, 152, 0, 0.45);
  transform: scale(1.06);
}

.info {
  text-align: center;
  color: rgba(255, 255, 255, 0.75);
  margin-bottom: 16px;
  min-height: 28px;
  font-size: 0.95rem;
  line-height: 1.5;
}

.info-success {
  color: #81c784;
  font-weight: 600;
}

.info-error {
  color: #e57373;
  font-weight: 600;
}

.steps {
  background: rgba(0, 0, 0, 0.25);
  border-radius: 14px;
  padding: 16px 20px;
  min-height: 52px;
  border: 1px solid rgba(255, 255, 255, 0.04);
}

.steps-title {
  color: rgba(255, 255, 255, 0.35);
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 8px;
}

.step-item {
  color: rgba(255, 255, 255, 0.85);
  padding: 4px 0;
  font-size: 1rem;
  font-family: 'Courier New', 'Consolas', monospace;
}

.step-item .step-result {
  color: #ffd54f;
  font-weight: 700;
}

.steps-empty {
  color: rgba(255, 255, 255, 0.2);
  font-size: 0.85rem;
  font-style: italic;
}

.challenge-header {
  display: none;
  justify-content: space-between;
  align-items: center;
  padding: 10px 16px;
  background: rgba(0, 0, 0, 0.25);
  border-radius: 12px;
  margin-bottom: 16px;
  border: 1px solid rgba(255, 255, 255, 0.04);
}

.challenge-timer {
  font-size: 1.3rem;
  font-weight: 700;
  color: #ffd54f;
  font-family: 'Courier New', 'Consolas', monospace;
}

.challenge-timer.warning {
  color: #ff8a65;
  animation: timerBlink 0.5s ease-in-out infinite alternate;
}

@keyframes timerBlink {
  from { opacity: 1; }
  to { opacity: 0.25; }
}

.challenge-score {
  font-size: 1.2rem;
  font-weight: 700;
  color: #81c784;
}

.overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2000;
}

.overlay-content {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 24px;
  padding: 40px 36px;
  max-width: 440px;
  width: 90%;
  text-align: center;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

.overlay-content h2 {
  color: #fff;
  font-size: 1.6rem;
  font-weight: 700;
  margin-bottom: 24px;
}

.challenge-rules {
  text-align: left;
  margin-bottom: 28px;
}

.challenge-rules p {
  color: rgba(255, 255, 255, 0.8);
  padding: 7px 0;
  line-height: 1.5;
  font-size: 0.95rem;
}

.challenge-buttons {
  display: flex;
  gap: 12px;
  justify-content: center;
}

.overlay-countdown {
  background: rgba(0, 0, 0, 0.88);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

.countdown-number {
  font-size: 10rem;
  font-weight: 900;
  color: #fff;
  text-shadow: 0 0 80px rgba(255, 255, 255, 0.2);
  animation: countdownPulse 1s ease-in-out;
  user-select: none;
}

@keyframes countdownPulse {
  0% { transform: scale(1.5); opacity: 0.2; }
  40% { transform: scale(1); opacity: 1; }
  100% { transform: scale(0.9); opacity: 0.6; }
}

@keyframes cardShimmer {
  0% { transform: translateX(-120%) rotate(5deg); }
  100% { transform: translateX(120%) rotate(5deg); }
}

@keyframes cardShuffle {
  0%   { transform: translateY(0) rotate(0deg) scale(1); }
  20%  { transform: translateY(-18px) rotate(6deg) scale(1.04); }
  40%  { transform: translateY(-4px) rotate(-3deg) scale(0.97); }
  60%  { transform: translateY(-12px) rotate(4deg) scale(1.02); }
  80%  { transform: translateY(-6px) rotate(-2deg) scale(0.99); }
  100% { transform: translateY(0) rotate(0deg) scale(1); }
}

.card-shuffling {
  animation: cardShuffle 0.5s ease-in-out;
}

.countdown-number.go {
  font-size: 7rem;
  color: #66bb6a;
  text-shadow: 0 0 80px rgba(102, 187, 106, 0.4);
}

.result-score {
  margin: 28px 0;
}

.result-score-value {
  font-size: 5rem;
  font-weight: 900;
  color: #ffd54f;
  display: block;
  line-height: 1;
}

.result-score-label {
  font-size: 1.1rem;
  color: rgba(255, 255, 255, 0.45);
  margin-top: 6px;
  display: block;
}

.result-stars {
  display: flex;
  justify-content: center;
  gap: 4px;
  margin-top: 8px;
  min-height: 32px;
}

.result-star {
  font-size: 1.8rem;
  color: #ffd54f;
  text-shadow: 0 0 12px rgba(255, 213, 79, 0.5);
  animation: starPop 0.3s ease-out backwards;
}

@keyframes starPop {
  0% { transform: scale(0); opacity: 0; }
  80% { transform: scale(1.2); }
  100% { transform: scale(1); opacity: 1; }
}

.btn-back-menu {
  position: fixed;
  top: 16px;
  right: 16px;
  z-index: 1000;
  padding: 8px 16px;
  background: rgba(255, 255, 255, 0.06);
  color: rgba(255, 255, 255, 0.35);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 10px;
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 600;
  transition: all 0.2s;
  backdrop-filter: blur(8px);
  cursor: pointer;
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
}

.btn-back-menu:hover {
  background: rgba(255, 255, 255, 0.12);
  color: #fff;
  border-color: rgba(255, 255, 255, 0.15);
  transform: translateY(-1px);
}

.menu-screen {
  text-align: center;
  padding: 48px 32px;
}

.menu-title {
  color: #fff;
  font-size: 3.2rem;
  font-weight: 800;
  letter-spacing: 2px;
  margin-bottom: 8px;
}

.menu-subtitle {
  color: rgba(255, 255, 255, 0.45);
  font-size: 1.1rem;
  margin-bottom: 48px;
}

.menu-footer {
  text-align: center;
  color: rgba(255, 255, 255, 0.15);
  font-size: 0.8rem;
  margin-top: 48px;
  font-weight: 600;
  letter-spacing: 1px;
}

.menu-leaderboard-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin-top: 24px;
  padding: 12px 28px;
  background: rgba(255, 215, 0, 0.08);
  border: 2px solid rgba(255, 215, 0, 0.2);
  border-radius: 14px;
  color: #ffd54f;
  text-decoration: none;
  font-size: 1rem;
  font-weight: 700;
  transition: all 0.25s ease;
  cursor: pointer;
}

.menu-leaderboard-link:hover {
  background: rgba(255, 215, 0, 0.15);
  border-color: rgba(255, 215, 0, 0.4);
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(255, 215, 0, 0.15);
}

/* Leaderboard Page */
.page-leaderboard .container {
  max-width: 640px;
}

.leaderboard-container {
  text-align: center;
}

.lb-tabs {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin: 28px 0 24px;
}

.lb-tab {
  padding: 10px 32px;
  border: 2px solid rgba(255, 255, 255, 0.1);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.04);
  color: rgba(255, 255, 255, 0.5);
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.2s;
  font-family: inherit;
}

.lb-tab:hover {
  background: rgba(255, 255, 255, 0.08);
  color: rgba(255, 255, 255, 0.8);
  border-color: rgba(255, 255, 255, 0.2);
}

.lb-tab.active {
  background: linear-gradient(135deg, #667eea, #764ba2);
  color: #fff;
  border-color: transparent;
  box-shadow: 0 4px 20px rgba(102, 126, 234, 0.35);
}

.lb-content {
  background: rgba(0, 0, 0, 0.2);
  border-radius: 16px;
  border: 1px solid rgba(255, 255, 255, 0.04);
  overflow: hidden;
}

.lb-table {
  width: 100%;
  border-collapse: collapse;
}

.lb-table th {
  padding: 14px 12px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: rgba(255, 255, 255, 0.3);
  text-align: left;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.lb-table td {
  padding: 12px;
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.85);
  border-bottom: 1px solid rgba(255, 255, 255, 0.03);
}

.lb-table tr:last-child td {
  border-bottom: none;
}

.lb-table tr:hover td {
  background: rgba(255, 255, 255, 0.03);
}

.col-rank {
  width: 60px;
  text-align: center !important;
  font-weight: 700;
}

.col-name {
  font-weight: 600;
  text-align: center !important;
}

.col-score {
  width: 100px;
  text-align: center !important;
}

.col-time {
  width: 140px;
  text-align: right !important;
  color: rgba(255, 255, 255, 0.4) !important;
  font-size: 0.8rem !important;
}

@media (max-width: 500px) {
  .lb-tab {
    padding: 8px 20px;
    font-size: 0.85rem;
  }

  .lb-table th,
  .lb-table td {
    padding: 10px 8px;
    font-size: 0.8rem;
  }

  .col-time {
    width: auto;
    font-size: 0.7rem !important;
  }

  .col-rank {
    width: 40px;
  }

  .col-score {
    width: 70px;
  }
}

.menu-options {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.menu-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 155px;
  height: 200px;
  background: rgba(255, 255, 255, 0.05);
  border: 2px solid rgba(255, 255, 255, 0.08);
  border-radius: 20px;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.25s ease;
}

.menu-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.18);
  transform: translateY(-8px);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
}

.menu-btn-battle {
  border-width: 2px;
  border-color: #ffd54f;
}

.menu-btn-battle:hover {
  border-color: #ffb300;
}

.menu-btn-num {
  font-size: 3.8rem;
  font-weight: 800;
  color: #fff;
  line-height: 1;
  margin-bottom: 12px;
}

.menu-btn-desc {
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.4);
  font-weight: 500;
}

.save-score {
  margin: 20px 0 12px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-items: center;
}

.save-score .setup-input {
  width: 100%;
  max-width: 260px;
  text-align: center;
  font-size: 1.1rem;
}

.btn-save {
  width: 100%;
  max-width: 260px;
  padding: 12px 20px;
  font-size: 0.95rem;
}

@media (max-width: 500px) {
  .container {
    padding: 24px 16px;
  }

  .card {
    width: 78px;
    height: 110px;
    border-radius: 9px;
  }

  .cards {
    gap: 10px;
    min-height: 120px;
  }

  .card-corner-top {
    top: 5px;
    left: 6px;
  }

  .card-corner-bottom {
    bottom: 5px;
    right: 6px;
  }

  .corner-value {
    font-size: 0.7rem;
  }

  .corner-suit {
    font-size: 0.5rem;
  }

  .center-value {
    font-size: 1.6rem;
  }

  .center-suit {
    font-size: 1.2rem;
  }

  .op-btn {
    width: 52px;
    height: 52px;
    font-size: 1.3rem;
  }

  header h1 {
    font-size: 1.6rem;
  }

  .menu-title {
    font-size: 2rem;
  }

  .menu-btn {
    width: 120px;
    height: 150px;
  }

  .menu-btn-num {
    font-size: 2.8rem;
  }
}

.setup-screen {
  max-width: 480px;
}

#gameScreen .container {
  max-width: 700px;
}

.setup-form {
  display: flex;
  flex-direction: column;
  gap: 18px;
  margin-top: 32px;
}

.setup-field {
  display: flex;
  flex-direction: column;
  gap: 6px;
  text-align: left;
}

.setup-label {
  color: rgba(255, 255, 255, 0.6);
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.setup-input {
  background: rgba(255, 255, 255, 0.06);
  border: 2px solid rgba(255, 255, 255, 0.1);
  border-radius: 12px;
  padding: 12px 16px;
  font-size: 1.2rem;
  font-weight: 700;
  color: #fff;
  outline: none;
  transition: border-color 0.2s;
  font-family: inherit;
}

.setup-input:focus {
  border-color: #667eea;
}

.setup-input::placeholder {
  color: rgba(255, 255, 255, 0.2);
  font-weight: 400;
}

.setup-error {
  color: #e57373;
  font-size: 0.85rem;
  font-weight: 600;
  min-height: 20px;
  text-align: center;
}

.btn-start {
  margin-top: 4px;
  padding: 14px 24px;
  font-size: 1.1rem;
}

.setup-note {
  color: rgba(255, 255, 255, 0.25);
  font-size: 0.8rem;
  text-align: center;
  line-height: 1.5;
  margin-top: 4px;
}

.impossible-text {
  color: #fff !important;
  font-size: 1.1rem;
  line-height: 1.7;
  padding: 8px 0 36px;
  margin: 0;
}

@media (max-width: 500px) {
.btn-back-menu {
    top: 10px;
    right: 10px;
    padding: 6px 12px;
    font-size: 0.75rem;
  }

  .countdown-number {
    font-size: 6rem;
  }

  .countdown-number.go {
    font-size: 4rem;
  }

  .overlay-content {
    padding: 28px 20px;
  }

  .overlay-content h2 {
    font-size: 1.3rem;
  }

  .result-score-value {
    font-size: 3.5rem;
  }

  .setup-input {
    font-size: 1rem;
    padding: 10px 14px;
  }

  .challenge-timer {
    font-size: 1rem;
  }

  .challenge-score {
    font-size: 1rem;
  }
}