/* 证明树动画样式 */

.proof-tree-container {
  background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
  border: 2px solid #dee2e6;
  border-radius: 16px;
  padding: 50px 40px;
  margin: 40px auto;
  max-width: 800px;
  min-height: 320px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.08);
  position: relative;
  overflow: hidden;
}

.proof-tree-container::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, #42b983, #3eaf7c, #42b983);
  border-radius: 16px 16px 0 0;
}

#proof-tree-content {
  font-family: 'Fira Code', 'Source Code Pro', 'Consolas', 'Monaco', monospace;
  font-size: 24px;
  line-height: 2;
  color: #2c3e50;
  margin: 0;
  text-align: center;
  white-space: pre;
  letter-spacing: 1px;
}

/* 推导线颜色 */
.proof-line {
  color: #42b983;
}

/* 规则标注颜色 */
.proof-rule {
  color: #e96900;
  font-weight: 600;
}

/* QED 样式 */
.proof-qed {
  color: #42b983;
  font-weight: 700;
  animation: qed-pulse 1.5s ease-in-out infinite;
}

@keyframes qed-pulse {
  0%, 100% {
    opacity: 1;
    transform: scale(1);
  }
  50% {
    opacity: 0.8;
    transform: scale(1.05);
  }
}

/* 光标闪烁 */
.typing-cursor {
  display: inline-block;
  width: 3px;
  height: 1.2em;
  background-color: #42b983;
  margin-left: 2px;
  animation: cursor-blink 0.8s step-end infinite;
  vertical-align: text-bottom;
}

@keyframes cursor-blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

/* 标题样式 */
.proof-title {
  color: #888;
  font-size: 14px;
  margin-bottom: 15px;
  text-transform: uppercase;
  letter-spacing: 2px;
}

/* 响应式适配 */
@media (max-width: 768px) {
  .proof-tree-container {
    padding: 30px 20px;
    margin: 30px 15px;
    min-height: 260px;
  }

  #proof-tree-content {
    font-size: 18px;
    line-height: 1.8;
  }
}

@media (max-width: 480px) {
  .proof-tree-container {
    padding: 25px 15px;
    min-height: 220px;
  }

  #proof-tree-content {
    font-size: 14px;
    line-height: 1.6;
  }
}