body {
  font-family: Arial, sans-serif;
  background: #d6e2f0;
  color: #162842;
  text-align: center;
  padding: 40px;
}

.app {
  max-width: 680px;
  margin: 0 auto;
}

h1 {
  font-size: 52px;
  margin-bottom: 10px;
}

h2 {
  font-size: 36px;
}

h3 {
  margin-top: 28px;
  margin-bottom: 10px;
}

#puzzle-label {
  font-weight: bold;
  margin-bottom: 6px;
}

#instructions {
  max-width: 520px;
  margin: 0 auto 24px auto;
  line-height: 1.4;
}

#current-number {
  font-size: 72px;
  margin: 20px 0;
  color: #162842;
}

.button-row {
  margin-bottom: 8px;
}

button {
  font-size: 20px;
  padding: 12px 18px;
  margin: 6px;
  border-radius: 10px;
  border: 2px solid #162842;
  background: #f8fbff;
  color: #162842;
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

button:hover {
  background: #c4d8ee;
}

button.selected {
  background: #162842;
  color: #f8fbff;
}

button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

#apply-button {
  margin-top: 15px;
  font-weight: bold;
}

#message {
  font-size: 20px;
  font-weight: bold;
  margin-top: 24px;
  min-height: 28px;
}

#history {
  list-style: none;
  padding: 0;
  margin: 0 auto 25px auto;
  font-size: 18px;
  max-width: 500px;
}

.history-item {
  background: #f8fbff;
  border: 2px solid #162842;
  border-left-width: 12px;
  border-radius: 12px;
  padding: 12px 14px;
  margin: 10px 0;
  text-align: left;
}

.history-top-line {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 6px;
}

.feedback-pill {
  font-size: 14px;
  font-weight: bold;
  padding: 4px 8px;
  border-radius: 999px;
  background: #d6e2f0;
}

.feedback-green {
  border-left-color: #2f8f5b;
}

.feedback-yellow {
  border-left-color: #d6a531;
}

.feedback-red {
  border-left-color: #b84646;
}

.end-screen {
  background: #f8fbff;
  border: 2px solid #162842;
  border-radius: 18px;
  padding: 28px;
  margin-top: 30px;
}

.share-grid {
  font-size: 32px;
  letter-spacing: 4px;
}

#share-status {
  font-weight: bold;
  min-height: 24px;
}

#countdown {
  font-size: 32px;
  font-weight: bold;
}

.hidden {
  display: none;
}

* {
  -webkit-tap-highlight-color: transparent;
}

@media (hover: none) and (pointer: coarse) {
  button:hover {
    background: #f8fbff;
  }

  button:active {
    background: #c4d8ee;
    transform: none;
  }

  button.selected {
    background: #162842;
    color: #f8fbff;
  }

  button.selected:hover {
    background: #162842;
    color: #f8fbff;
  }
}

@media (max-width: 600px) {
  body {
    padding: 10px 12px 80px 12px;
  }

  .app {
    max-width: 100%;
  }

  h1 {
    font-size: 34px;
    margin-top: 0;
    margin-bottom: 4px;
  }

  h2 {
    font-size: 24px;
  }

  h3 {
    font-size: 17px;
    margin-top: 12px;
    margin-bottom: 5px;
  }

  p {
    margin-top: 6px;
    margin-bottom: 6px;
  }

  #puzzle-label {
    font-size: 15px;
    margin-bottom: 2px;
  }

  #instructions {
    font-size: 13px;
    margin-bottom: 10px;
    line-height: 1.25;
  }

  #current-number {
    font-size: 50px;
    margin: 6px 0;
  }

  .button-row {
    margin-bottom: 2px;
  }

  button {
    font-size: 17px;
    padding: 9px 13px;
    margin: 3px;
    border-radius: 9px;
  }

  #apply-button {
    font-size: 17px;
    padding: 9px 16px;
    margin-top: 6px;
  }

  #message {
    font-size: 15px;
    margin-top: 8px;
    min-height: 18px;
  }

  #history {
    max-width: 100%;
    font-size: 15px;
    margin-bottom: 14px;
  }

  .history-item {
    font-size: 14px;
    padding: 9px 10px;
    margin: 7px 0;
  }

  .feedback-pill {
    font-size: 12px;
  }

  .end-screen {
    padding: 18px 14px;
  }

  .share-grid {
    font-size: 26px;
  }

  #countdown {
    font-size: 26px;
  }
}