/* ===== Reset & Base ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  -webkit-text-size-adjust: 100%;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  color: #333;
  background-color: #f5f5f5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  user-select: none;
  -webkit-user-select: none;
  overscroll-behavior-y: none;
}

/* ===== View System ===== */
.view {
  display: none;
  min-height: 100vh;
  padding-top: 56px;
}

.view.active {
  display: block;
}

/* ===== Header ===== */
.app-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 56px;
  background: #1677ff;
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 0 16px;
}

.app-header h1 {
  font-size: 18px;
  font-weight: 600;
}

.btn-back {
  position: absolute;
  left: 8px;
  top: 50%;
  transform: translateY(-50%);
  background: transparent;
  border: none;
  color: #fff;
  font-size: 28px;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  line-height: 1;
  padding-bottom: 4px;
}

/* ===== Container ===== */
.container {
  max-width: 600px;
  margin: 0 auto;
  padding: 16px;
}

/* ===== Buttons ===== */
.btn-primary,
.btn-secondary {
  display: block;
  width: 100%;
  padding: 14px 24px;
  border-radius: 8px;
  font-size: 16px;
  font-weight: 500;
  text-align: center;
  cursor: pointer;
  border: none;
  transition: all 0.2s ease;
  min-height: 48px;
  user-select: none;
  -webkit-user-select: none;
  touch-action: manipulation;
}

.btn-primary {
  background: #1677ff;
  color: #fff;
}

.btn-primary:active {
  background: #0958d9;
  transform: scale(0.98);
}

.btn-secondary {
  background: #fff;
  color: #1677ff;
  border: 1px solid #1677ff;
}

.btn-secondary:active {
  background: #e6f4ff;
  transform: scale(0.98);
}

.btn-large {
  padding: 16px 24px;
  font-size: 17px;
  min-height: 52px;
}

.btn-icon {
  font-size: 20px;
  margin-right: 4px;
}

/* ===== Section Title ===== */
.section-title {
  font-size: 16px;
  font-weight: 600;
  color: #666;
  margin: 24px 0 12px;
}

/* ===== Empty Tip ===== */
.empty-tip {
  text-align: center;
  color: #999;
  padding: 40px 16px;
  font-size: 14px;
}

/* ===== Form ===== */
.form-group {
  margin-bottom: 24px;
}

.form-label {
  display: block;
  font-size: 15px;
  font-weight: 500;
  color: #333;
  margin-bottom: 12px;
}

.form-hint {
  font-size: 13px;
  color: #999;
  margin-top: 8px;
}

/* ===== Checkbox Group ===== */
.checkbox-group {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.checkbox-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  background: #fff;
  border-radius: 10px;
  cursor: pointer;
  transition: background 0.2s;
  min-height: 52px;
}

.checkbox-item:active {
  background: #f0f0f0;
}

.checkbox-item input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.checkbox-box {
  width: 22px;
  height: 22px;
  border: 2px solid #d9d9d9;
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: all 0.2s;
}

.checkbox-item input:checked + .checkbox-box {
  background: #1677ff;
  border-color: #1677ff;
}

.checkbox-item input:checked + .checkbox-box::after {
  content: "\2713";
  color: #fff;
  font-size: 14px;
  font-weight: bold;
}

.checkbox-text {
  font-size: 15px;
  color: #333;
  flex: 1;
}

.count-badge {
  display: inline-block;
  background: #f0f0f0;
  color: #666;
  font-size: 12px;
  padding: 2px 8px;
  border-radius: 10px;
  margin-left: 6px;
}

/* ===== Count Control (Slider + Input) ===== */
.count-control {
  display: flex;
  align-items: center;
  gap: 12px;
  background: #fff;
  padding: 12px 16px;
  border-radius: 10px;
}

.slider {
  flex: 1;
  -webkit-appearance: none;
  appearance: none;
  height: 6px;
  border-radius: 3px;
  background: #e8e8e8;
  outline: none;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: #1677ff;
  cursor: pointer;
  box-shadow: 0 2px 6px rgba(22, 119, 255, 0.3);
}

.slider::-moz-range-thumb {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: #1677ff;
  cursor: pointer;
  border: none;
  box-shadow: 0 2px 6px rgba(22, 119, 255, 0.3);
}

.number-input {
  width: 64px;
  height: 40px;
  border: 1px solid #d9d9d9;
  border-radius: 8px;
  text-align: center;
  font-size: 16px;
  font-weight: 500;
  color: #333;
  -moz-appearance: textfield;
}

.number-input::-webkit-outer-spin-button,
.number-input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.number-input:focus {
  border-color: #1677ff;
  outline: none;
}

/* ===== Toggle Switch ===== */
.toggle-item {
  display: flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
  padding: 4px 0;
}

.toggle-item input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.toggle-track {
  width: 48px;
  height: 26px;
  background: #d9d9d9;
  border-radius: 13px;
  position: relative;
  flex-shrink: 0;
  transition: background 0.3s;
}

.toggle-thumb {
  position: absolute;
  top: 3px;
  left: 3px;
  width: 20px;
  height: 20px;
  background: #fff;
  border-radius: 50%;
  transition: transform 0.3s;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}

.toggle-item input:checked + .toggle-track {
  background: #1677ff;
}

.toggle-item input:checked + .toggle-track .toggle-thumb {
  transform: translateX(22px);
}

.toggle-text {
  font-size: 15px;
  color: #333;
}

/* ===== Progress Bar ===== */
.progress-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.progress-track {
  flex: 1;
  height: 6px;
  background: #e8e8e8;
  border-radius: 3px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: #1677ff;
  border-radius: 3px;
  transition: width 0.3s ease;
  width: 5%;
}

.progress-text {
  font-size: 13px;
  color: #666;
  white-space: nowrap;
  flex-shrink: 0;
}

/* ===== Question Type Badge ===== */
.question-type {
  display: inline-block;
  font-size: 12px;
  font-weight: 500;
  color: #1677ff;
  background: #e6f4ff;
  padding: 4px 12px;
  border-radius: 12px;
  margin-bottom: 12px;
}

/* ===== Question Card ===== */
.question-card {
  background: #fff;
  border-radius: 12px;
  padding: 20px 16px;
  margin-bottom: 16px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
}

.question-text {
  font-size: 16px;
  font-weight: 500;
  color: #1a1a1a;
  line-height: 1.6;
  margin-bottom: 16px;
}

/* ===== Options ===== */
.options-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.option-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 16px;
  background: #f8f8f8;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.2s ease;
  border: 2px solid transparent;
  min-height: 52px;
}

.option-item:active {
  background: #f0f0f0;
}

.option-key {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: #e8e8e8;
  color: #666;
  font-size: 13px;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin-top: 1px;
}

.option-text {
  font-size: 15px;
  color: #333;
  line-height: 1.5;
  flex: 1;
  padding-top: 2px;
}

/* Option States */
.option-item.selected {
  background: #e6f4ff;
  border-color: #1677ff;
}

.option-item.selected .option-key {
  background: #1677ff;
  color: #fff;
}

.option-item.correct {
  background: #f6ffed;
  border-color: #52c41a;
}

.option-item.correct .option-key {
  background: #52c41a;
  color: #fff;
}

.option-item.wrong {
  background: #fff2f0;
  border-color: #ff4d4f;
}

.option-item.wrong .option-key {
  background: #ff4d4f;
  color: #fff;
}

.option-item.disabled {
  opacity: 0.6;
  pointer-events: none;
}

/* ===== True/False Buttons ===== */
.tf-buttons {
  display: flex;
  gap: 12px;
  margin-top: 4px;
}

.tf-btn {
  flex: 1;
  padding: 14px;
  border-radius: 10px;
  font-size: 16px;
  font-weight: 500;
  text-align: center;
  cursor: pointer;
  border: 2px solid #d9d9d9;
  background: #fff;
  color: #333;
  transition: all 0.2s ease;
  min-height: 52px;
  touch-action: manipulation;
}

.tf-btn:active {
  background: #f5f5f5;
}

.tf-btn.selected {
  background: #e6f4ff;
  border-color: #1677ff;
  color: #1677ff;
}

.tf-btn.correct {
  background: #f6ffed;
  border-color: #52c41a;
  color: #52c41a;
}

.tf-btn.wrong {
  background: #fff2f0;
  border-color: #ff4d4f;
  color: #ff4d4f;
}

/* ===== Answer Feedback ===== */
.answer-feedback {
  background: #fff;
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 16px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
}

.feedback-text {
  font-size: 15px;
  font-weight: 500;
  margin-bottom: 8px;
}

.feedback-text.correct-text {
  color: #52c41a;
}

.feedback-text.wrong-text {
  color: #ff4d4f;
}

.feedback-text.partial {
  color: #fa8c16;
}

.correct-answer {
  font-size: 14px;
  color: #666;
  line-height: 1.5;
}

.correct-answer strong {
  color: #52c41a;
}

/* ===== Action Buttons ===== */
.action-buttons {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

/* ===== Result Page ===== */
.result-header {
  text-align: center;
  padding: 32px 0 24px;
}

.result-icon {
  width: 72px;
  height: 72px;
  background: #f6ffed;
  color: #52c41a;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 36px;
  margin: 0 auto 16px;
}

.result-title {
  font-size: 22px;
  font-weight: 600;
  color: #1a1a1a;
}

.result-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  margin-bottom: 32px;
}

.stat-item {
  background: #fff;
  border-radius: 12px;
  padding: 16px 8px;
  text-align: center;
}

.stat-value {
  display: block;
  font-size: 24px;
  font-weight: 700;
  color: #1a1a1a;
  margin-bottom: 4px;
}

.stat-correct {
  color: #52c41a;
}

.stat-wrong {
  color: #ff4d4f;
}

.stat-label {
  font-size: 12px;
  color: #999;
}

.result-actions {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

/* ===== History List ===== */
.history-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.history-item {
  background: #fff;
  border-radius: 12px;
  padding: 16px;
  display: flex;
  flex-direction: column;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
  cursor: pointer;
  transition: background 0.2s;
}

.history-item:active {
  background: #f8f8f8;
}

.history-info {
  flex: 1;
}

.history-date {
  font-size: 14px;
  font-weight: 500;
  color: #333;
  margin-bottom: 4px;
}

.history-detail {
  font-size: 12px;
  color: #999;
}

.history-stats {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 2px;
}

.history-stat-row {
  font-size: 12px;
  color: #999;
  line-height: 1.4;
}

.history-stat-row.stat-high {
  color: #52c41a;
}

.history-stat-row.stat-mid {
  color: #fa8c16;
}

.history-stat-row.stat-low {
  color: #ff4d4f;
}

.history-main {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex: 1;
  min-width: 0;
}

.history-actions {
  display: flex;
  gap: 6px;
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px solid #f0f0f0;
}

.btn-action {
  padding: 6px 12px;
  font-size: 13px;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  user-select: none;
}

.btn-view-wrong {
  background: #e6f4ff;
  color: #1677ff;
}

.btn-continue {
  background: #f6ffed;
  color: #52c41a;
}

.btn-delete {
  background: #fff2f0;
  color: #ff4d4f;
}

/* ===== Wrong Answers List ===== */
.wrong-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 20px;
}

.wrong-item {
  background: #fff;
  border-radius: 12px;
  padding: 16px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
}

.wrong-question {
  font-size: 15px;
  font-weight: 500;
  color: #1a1a1a;
  line-height: 1.5;
  margin-bottom: 12px;
}

.wrong-answer-row {
  display: flex;
  gap: 16px;
  font-size: 14px;
}

.wrong-user {
  color: #ff4d4f;
}

.wrong-correct {
  color: #52c41a;
}

.wrong-answer-row strong {
  font-weight: 600;
}

/* ===== Utilities ===== */
.hidden {
  display: none !important;
}

/* ===== Responsive: Small screens ===== */
@media (max-width: 360px) {
  .container {
    padding: 12px;
  }

  .result-stats {
    gap: 6px;
  }

  .stat-item {
    padding: 12px 4px;
  }

  .stat-value {
    font-size: 20px;
  }

  .question-card {
    padding: 16px 12px;
  }

  .option-item {
    padding: 12px;
  }

  .checkbox-item {
    padding: 12px;
  }
}

/* ===== Safe area for notched devices ===== */
@supports (padding-top: env(safe-area-inset-top)) {
  .view {
    padding-top: calc(56px + env(safe-area-inset-top));
  }

  .app-header {
    padding-top: env(safe-area-inset-top);
    height: calc(56px + env(safe-area-inset-top));
  }
}

/* ===== PWA & Polish ===== */

/* 禁用文本选择(提升点击体验) */
.option-item, .tf-btn, .btn-primary, .btn-secondary, .history-item {
  user-select: none;
  -webkit-user-select: none;
}

/* 平滑过渡 */
.option-item, .tf-btn, .btn-primary, .btn-secondary {
  transition: all 0.15s ease;
}

/* 选项 Hover(桌面端) */
@media (hover: hover) {
  .option-item:hover:not(.disabled) {
    border-color: #1677ff;
  }
}

/* 结果页数字高亮 */
#stat-rate { color: #1677ff; font-weight: 600; }

/* 错题页正确答案高亮 */
.correct-answer-display { color: #52c41a; font-weight: 500; }
.user-answer-display { color: #ff4d4f; }

/* 空状态 */
.empty-state {
  text-align: center; padding: 40px 20px;
  color: #999;
}

/* 滚动优化 */
html { scroll-behavior: smooth; }
body { overscroll-behavior-y: contain; }

/* ===== Accuracy Bar ===== */
.accuracy-bar {
  font-size: 13px;
  color: #666;
  text-align: right;
  margin-bottom: 12px;
  margin-top: -8px;
}

.accuracy-bar.accuracy-high {
  color: #52c41a;
  font-weight: 600;
}

.accuracy-bar.accuracy-mid {
  color: #fa8c16;
  font-weight: 600;
}

.accuracy-bar.accuracy-low {
  color: #ff4d4f;
  font-weight: 600;
}

/* ===== Bank List ===== */
.bank-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.bank-item {
  background: #fff;
  border-radius: 12px;
  padding: 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  transition: background 0.2s;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
}

.bank-item:active {
  background: #f8f8f8;
}

.bank-name {
  font-size: 16px;
  font-weight: 600;
  color: #1a1a1a;
  margin-bottom: 4px;
}

.bank-count {
  font-size: 13px;
  color: #999;
}

.bank-arrow {
  font-size: 20px;
  color: #999;
  font-weight: 300;
}