:root {
    --primary-color: #2c3e50;
    --accent-color: #3498db;
    --bg-color: #f8f9fa;
    --border-color: #e2e8f0;
    --success-color: #2ecc71;
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; }
body { background-color: var(--bg-color); color: var(--primary-color); padding-bottom: 60px; }

.app-header { display: flex; justify-content: space-between; align-items: center; padding: 15px 30px; background: #1a252f; color: white; }
.logo { font-size: 20px; font-weight: bold; color: var(--accent-color); }
.save-status { font-size: 13px; color: #2ecc71; opacity: 0; transition: opacity 0.3s; }
.save-status.visible { opacity: 1; }

.container { max-width: 900px; margin: 30px auto; padding: 0 20px; }

/* Onglets de navigation entre les tests */
.tabs-container { display: flex; gap: 10px; margin-bottom: 25px; border-bottom: 2px solid var(--border-color); overflow-x: auto; }
.tab-btn { padding: 12px 20px; border: none; background: #e2e8f0; cursor: pointer; border-radius: 8px 8px 0 0; font-weight: 600; color: #4a5568; }
.tab-btn.active { background: var(--accent-color); color: white; }
.tab-btn.completed::after { content: " ✓"; color: var(--success-color); }

.validation-panel { margin-top: 40px; padding: 25px; background: white; border-radius: 8px; border: 1px solid var(--border-color); text-align: center; }
.progress-summary { margin-bottom: 15px; font-weight: 600; color: #718096; }

.btn { padding: 12px 25px; border: none; border-radius: 6px; font-weight: bold; cursor: pointer; }
.btn-primary { background: var(--accent-color); color: white; }
.btn-primary:disabled { background: #cbd5e0; cursor: not-allowed; }
.btn-large { font-size: 16px; width: 100%; }