/* ===== 质量与密度交互实验室 ===== */
:root { --primary: #9B59B6; --primary-light: #BA68C8; --primary-dark: #7D3C98; --bg: #F5F0F9; }
.container { max-width: 1200px; margin: 0 auto; padding: 1rem; }
.lab-header { display: flex; align-items: center; justify-content: space-between; padding: 1rem 1.5rem; background: linear-gradient(135deg, var(--primary), var(--primary-light)); border-radius: 16px; margin-bottom: 1rem; color: #fff; }
.lab-title { font-size: 1.5rem; font-weight: 700; }
.back-btn { background: rgba(255,255,255,0.2); color: #fff; border: 1px solid rgba(255,255,255,0.3); padding: 0.5rem 1rem; border-radius: 8px; cursor: pointer; }
.mastery-badge { background: rgba(255,255,255,0.2); padding: 0.4rem 1rem; border-radius: 20px; font-weight: 600; }
.progress-track { display: flex; gap: 0.3rem; margin-bottom: 1rem; overflow-x: auto; padding: 0.5rem; }
.progress-step { flex: 1; min-width: 80px; text-align: center; padding: 0.5rem; border-radius: 8px; background: #EDE7F6; cursor: pointer; }
.progress-step.active { background: var(--primary); color: #fff; }
.progress-step-label { font-size: 0.75rem; font-weight: 600; }
.module-tabs { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-bottom: 1rem; }
.module-tab { flex: 1; min-width: 100px; padding: 0.6rem 1rem; border: 2px solid #E0E0E0; border-radius: 10px; background: #fff; cursor: pointer; font-weight: 600; font-size: 0.9rem; }
.module-tab.active { border-color: var(--primary); background: var(--primary); color: #fff; }
.module-content { display: none; }
.module-content.active { display: block; }
.module-card { background: #fff; border-radius: 16px; padding: 1.5rem; border: 2px solid #EDE7F6; }
.module-header { display: flex; align-items: center; gap: 1rem; margin-bottom: 1rem; }
.module-num { width: 40px; height: 40px; border-radius: 10px; background: var(--primary); color: #fff; display: flex; align-items: center; justify-content: center; font-weight: 700; }
.module-title { font-size: 1.2rem; font-weight: 700; }
.socrates-chat { min-height: 200px; max-height: 400px; overflow-y: auto; }
.socrates-input-area { display: flex; gap: 0.5rem; margin-top: 1rem; }
.socrates-input { flex: 1; padding: 0.8rem 1rem; border: 2px solid #EDE7F6; border-radius: 10px; font-size: 1rem; }
.socrates-send { padding: 0.8rem 1.5rem; background: var(--primary); color: #fff; border: none; border-radius: 10px; cursor: pointer; font-weight: 600; }
@media (max-width: 768px) { .lab-header { flex-direction: column; } .progress-step { min-width: 60px; font-size: 0.7rem; } }