/* ============================================
   GOUP 语法深度学习链样式
   移动端优先 (375px 基准)
   ============================================ */

.grammar-flow {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  max-width: 600px;
  margin: 0 auto;
  background: #fafafa;
}

/* ─── 头部 + 步骤指示器 ─── */
.gf-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  background: #fff;
  border-bottom: 1px solid #eee;
  flex-shrink: 0;
}
.gf-step-indicator {
  display: flex;
  align-items: center;
  gap: 0;
}
.gf-step {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: #E0E0E0;
  color: #999;
  font-size: 13px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
}
.gf-step.active {
  background: linear-gradient(135deg, #FFD700, #FF9800);
  color: #fff;
  box-shadow: 0 2px 8px rgba(255,152,0,0.3);
}
.gf-step.done {
  background: #4CAF50;
  color: #fff;
}
.gf-line {
  width: 20px;
  height: 2px;
  background: #E0E0E0;
  transition: background 0.3s;
}
.gf-step.done + .gf-line {
  background: #4CAF50;
}

.gf-close {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: none;
  background: rgba(0,0,0,0.05);
  font-size: 18px;
  cursor: pointer;
}

/* ─── 内容区 ─── */
.gf-body {
  flex: 1;
  overflow-y: auto;
  padding: 20px 16px;
  -webkit-overflow-scrolling: touch;
}

/* ─── Step 1: 讲解 ─── */
.gf-explain-title {
  font-size: 20px;
  font-weight: 700;
  color: #333;
  margin-bottom: 14px;
}
.gf-explain-text {
  font-size: 15px;
  line-height: 1.7;
  color: #555;
  background: #FFFDE7;
  border-radius: 12px;
  padding: 14px 16px;
  margin-bottom: 16px;
}
.gf-explain-text b {
  color: #E65100;
}

.gf-examples {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 14px;
}
.gf-example-item {
  background: #fff;
  border-radius: 10px;
  padding: 12px 14px;
  border: 1px solid #eee;
}
.gf-example-en {
  font-size: 16px;
  font-weight: 600;
  color: #333;
}
.gf-example-zh {
  font-size: 13px;
  color: #999;
  margin-top: 4px;
}

.gf-tip {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  background: #E8F5E9;
  border-radius: 12px;
  padding: 12px 14px;
  font-size: 14px;
  color: #2E7D32;
  line-height: 1.5;
}
.gf-tip-icon {
  font-size: 18px;
  flex-shrink: 0;
}

.gf-hint-text {
  font-size: 13px;
  color: #999;
  margin-bottom: 16px;
}

/* ─── Step 2: 填空 ─── */
.gf-fill-item {
  background: #fff;
  border-radius: 12px;
  padding: 14px;
  margin-bottom: 12px;
  border: 1px solid #eee;
}
.gf-fill-sentence {
  font-size: 17px;
  font-weight: 600;
  color: #333;
  margin-bottom: 10px;
}
.gf-blank {
  display: inline-block;
  min-width: 60px;
  border-bottom: 2px dashed #FFD700;
  padding: 0 4px;
  color: #FF9800;
}
.gf-fill-input-row {
  display: flex;
  align-items: center;
  gap: 10px;
}
.gf-fill-hint {
  font-size: 12px;
  color: #999;
  flex-shrink: 0;
}
.gf-fill-input {
  flex: 1;
  border: 1px solid #E0E0E0;
  border-radius: 8px;
  padding: 8px 12px;
  font-size: 16px;
  outline: none;
  transition: border-color 0.2s;
}
.gf-fill-input:focus {
  border-color: #FFD700;
}
.gf-fill-feedback {
  margin-top: 8px;
  font-size: 14px;
  font-weight: 500;
}

/* ─── Step 3: 选择题 ─── */
.gf-quiz-item {
  background: #fff;
  border-radius: 12px;
  padding: 14px;
  margin-bottom: 12px;
  border: 1px solid #eee;
}
.gf-quiz-qnum {
  font-size: 12px;
  color: #999;
  margin-bottom: 6px;
}
.gf-quiz-question {
  font-size: 16px;
  font-weight: 500;
  color: #333;
  margin-bottom: 10px;
  line-height: 1.5;
}
.gf-quiz-options {
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.gf-quiz-opt {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1.5px solid #E0E0E0;
  cursor: pointer;
  transition: all 0.15s;
  font-size: 15px;
}
.gf-quiz-opt:active {
  transform: scale(0.98);
}
.gf-quiz-opt.selected {
  border-color: #FFD700;
  background: #FFFDE7;
}
.gf-quiz-opt.correct {
  border-color: #4CAF50;
  background: #E8F5E9;
}
.gf-quiz-opt.wrong {
  border-color: #EF5350;
  background: #FFEBEE;
}
.gf-quiz-opt-letter {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: #F5F5F5;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 700;
  color: #666;
  flex-shrink: 0;
}
.gf-quiz-opt.selected .gf-quiz-opt-letter {
  background: #FFD700;
  color: #fff;
}

/* ─── Step 4: 错题讲题 ─── */
.gf-review-item {
  background: #FFF3E0;
  border-radius: 12px;
  padding: 14px;
  margin-bottom: 12px;
  border: 1px solid #FFE082;
}
.gf-review-q {
  font-size: 15px;
  font-weight: 600;
  color: #333;
  margin-bottom: 8px;
}
.gf-review-opts {
  font-size: 13px;
  color: #999;
  margin-bottom: 8px;
}
.gf-review-wrong {
  font-size: 14px;
  color: #EF5350;
  margin-bottom: 4px;
}
.gf-review-correct {
  font-size: 14px;
  color: #4CAF50;
  font-weight: 500;
  margin-bottom: 8px;
}
.gf-review-tip {
  font-size: 13px;
  color: #E65100;
  line-height: 1.5;
}

/* ─── 底部按钮 ─── */
.gf-actions {
  display: flex;
  gap: 10px;
  padding: 14px 16px;
  background: #fff;
  border-top: 1px solid #eee;
  flex-shrink: 0;
  padding-bottom: max(14px, env(safe-area-inset-bottom));
}
.gf-btn-half {
  flex: 1;
  padding: 14px;
  font-size: 15px;
  border-radius: 12px;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: transform 0.15s;
}
.gf-btn-half:active {
  transform: scale(0.96);
}