* { box-sizing: border-box; margin: 0; padding: 0; }
body { 
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; 
    background-color: #f4f7f6; color: #333; line-height: 1.6;
    display: flex; justify-content: center; align-items: center; min-height: 100vh;
    padding: 20px 10px;
}

.screen { display: none; width: 100%; max-width: 600px; padding: 30px 20px; background: white; border-radius: 16px; box-shadow: 0 10px 30px rgba(0,0,0,0.05); }
.screen.active { display: block; animation: fadeIn 0.4s ease-out; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

h1 { font-size: 26px; text-align: center; margin-bottom: 10px; color: #1a1a1a;}
h2 { font-size: 22px; text-align: center; margin-bottom: 20px; color: #2c3e50;}
.subtitle { text-align: center; color: #666; margin-bottom: 30px; font-size: 15px;}

/* 历史记录卡片样式 */
.history-card { 
    background: #e8f4fd; border: 2px dashed #3498db; border-radius: 12px; 
    padding: 15px; margin-bottom: 25px; text-align: center; cursor: pointer; 
    color: #2c3e50; font-weight: bold; transition: all 0.2s;
}
.history-card:active { transform: scale(0.98); background: #d6eaf8; }

.mode-selection { display: flex; flex-direction: column; gap: 15px; }
.mode-card { 
    background: #fff; border: 2px solid #e9ecef; border-radius: 12px; padding: 20px; 
    cursor: pointer; transition: all 0.2s; position: relative;
}
@media (hover: hover) { .mode-card:hover { border-color: #3498db; box-shadow: 0 4px 15px rgba(52,152,219,0.1); transform: translateY(-2px); } }
.mode-card:active { border-color: #3498db; transform: scale(0.98); }
.mode-card h3 { font-size: 18px; margin-bottom: 5px; color: #2c3e50; }
.mode-card p { font-size: 13px; color: #7f8c8d; }
.mode-card.recommended { border-color: #f39c12; background: #fffcf5;}
.badge { position: absolute; top: -10px; right: 20px; background: #f39c12; color: white; font-size: 12px; padding: 2px 8px; border-radius: 10px; font-weight: bold;}

.btn-primary { 
    display: block; width: 100%; padding: 15px; font-size: 16px; font-weight: bold; 
    background-color: #2c3e50; color: white; border: none; border-radius: 8px; cursor: pointer; transition: background 0.3s; 
}
.btn-primary:active { background-color: #1a252f; transform: scale(0.98); }

/* 顶部状态栏（包含返回按钮和进度数字） */
.top-bar { display: flex; justify-content: space-between; align-items: center; margin-bottom: 10px; }
.text-btn { background: none; border: none; color: #7f8c8d; font-size: 14px; cursor: pointer; font-weight: bold;}
.text-btn:active { color: #3498db; }
.progress-text { font-size: 13px; color: #888; }

.progress-container { width: 100%; height: 6px; background: #eee; border-radius: 3px; margin-bottom: 25px; overflow: hidden; }
#progress-bar { height: 100%; background: #3498db; width: 0%; transition: width 0.3s ease; }

#question-text { font-size: 20px; margin-bottom: 15px; line-height: 1.5; transition: opacity 0.2s; text-align: left;}
.options-group { display: flex; flex-direction: column; gap: 10px; margin-top: 20px; }
.option-btn { 
    padding: 14px 15px; font-size: 15px; background: #f8f9fa; border: 2px solid #e9ecef; 
    border-radius: 8px; cursor: pointer; text-align: left; transition: all 0.2s; color: #333;
}
@media (hover: hover) { .option-btn:hover { background: #e8f4fd; border-color: #3498db; } }
.option-btn:active { background: #e8f4fd; border-color: #3498db; transform: scale(0.98); }

.help-section { margin-bottom: 20px; text-align: left;}
.help-icon { font-size: 13px; color: #e67e22; cursor: pointer; font-weight: bold; border-bottom: 1px dashed #e67e22; }
.help-text { font-size: 13px; color: #666; background: #fff8e1; padding: 10px; border-radius: 6px; margin-top: 10px; border-left: 3px solid #e67e22; }

.analysis-box { margin-top: 20px; padding: 20px; background: #f8f9fa; border-radius: 8px; font-size: 14px; color: #444; line-height: 1.6;}