:root{--bg: #1a1a2e;--bg-card: #16213e;--bg-card-hover: #1a2744;--text: #e0e0e0;--text-muted: #8b8fa3;--primary: #6c63ff;--primary-hover: #5a52d5;--accent: #00d2ff;--success: #00e676;--warning: #ffab40;--danger: #ff5252;--border: rgba(255, 255, 255, .06);--radius: 14px;--shadow: 0 4px 24px rgba(0, 0, 0, .3)}.app.light{--bg: #f0f2f5;--bg-card: #ffffff;--bg-card-hover: #f8f9fa;--text: #1a1a2e;--text-muted: #6b7280;--border: rgba(0, 0, 0, .08);--shadow: 0 2px 12px rgba(0, 0, 0, .08)}*{margin:0;padding:0;box-sizing:border-box}body{font-family:Inter,-apple-system,BlinkMacSystemFont,sans-serif;background:var(--bg);color:var(--text);-webkit-font-smoothing:antialiased;overflow-x:hidden}.app{min-height:100vh;padding-bottom:24px}.app-header{display:flex;align-items:center;justify-content:space-between;padding:16px 20px;background:linear-gradient(135deg,var(--primary),#4a47a3);color:#fff}.app-header h1{font-size:1.25rem;font-weight:700}.user-badge{background:#fff3;padding:4px 12px;border-radius:20px;font-size:.85rem;font-weight:500;-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px)}.loading-screen,.error-screen{display:flex;flex-direction:column;align-items:center;justify-content:center;height:100vh;gap:16px}.spinner{width:40px;height:40px;border:3px solid var(--border);border-top-color:var(--primary);border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.exam-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(140px,1fr));gap:12px;padding:20px}.exam-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:20px 14px;text-align:center;cursor:pointer;transition:all .2s ease;box-shadow:var(--shadow)}.exam-card:hover,.exam-card:active{background:var(--bg-card-hover);transform:translateY(-2px);border-color:var(--primary)}.exam-card .emoji{font-size:2rem;display:block;margin-bottom:8px}.exam-card .name{font-weight:600;font-size:.95rem}.exam-card .desc{font-size:.75rem;color:var(--text-muted);margin-top:4px}.section-title{font-size:1.1rem;font-weight:700;padding:20px 20px 8px;color:var(--text)}.dashboard{padding:0 0 20px}.stats-row{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;padding:16px 20px}.stat-card{background:var(--bg-card);border-radius:var(--radius);padding:14px;text-align:center;border:1px solid var(--border)}.stat-card .value{font-size:1.5rem;font-weight:700;background:linear-gradient(135deg,var(--primary),var(--accent));-webkit-background-clip:text;-webkit-text-fill-color:transparent}.stat-card .label{font-size:.7rem;color:var(--text-muted);margin-top:4px;text-transform:uppercase;letter-spacing:.5px}.action-list{padding:0 20px;display:flex;flex-direction:column;gap:10px}.action-btn{display:flex;align-items:center;gap:14px;background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:16px 18px;cursor:pointer;transition:all .15s ease;color:var(--text);font-size:1rem;width:100%;text-align:left}.action-btn:hover{background:var(--bg-card-hover);transform:translate(4px)}.action-btn .icon{font-size:1.4rem}.action-btn .label{font-weight:600}.action-btn .sublabel{font-size:.75rem;color:var(--text-muted)}.change-exam-btn{display:block;margin:20px auto 0;padding:10px 24px;background:transparent;border:1px solid var(--border);border-radius:20px;color:var(--text-muted);cursor:pointer;font-size:.85rem;transition:all .2s}.change-exam-btn:hover{border-color:var(--primary);color:var(--primary)}.practice-screen{padding:20px}.question-card{background:var(--bg-card);border-radius:var(--radius);padding:24px 20px;border:1px solid var(--border);box-shadow:var(--shadow);margin-bottom:16px}.question-card .q-number{font-size:.75rem;color:var(--text-muted);text-transform:uppercase;letter-spacing:1px;margin-bottom:8px}.question-card .q-text{font-size:1.05rem;font-weight:500;line-height:1.5}.options-list{display:flex;flex-direction:column;gap:10px;margin-top:16px}.option-btn{display:flex;align-items:center;gap:12px;background:var(--bg-card);border:2px solid var(--border);border-radius:12px;padding:14px 16px;cursor:pointer;transition:all .15s ease;color:var(--text);font-size:.95rem;width:100%;text-align:left}.option-btn:hover{border-color:var(--primary);background:var(--bg-card-hover)}.option-btn.selected{border-color:var(--primary);background:#6c63ff1a}.option-btn.correct{border-color:var(--success);background:#00e6761a}.option-btn.incorrect{border-color:var(--danger);background:#ff52521a}.option-btn .letter{width:28px;height:28px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:.8rem;background:var(--border);flex-shrink:0}.submit-btn,.next-btn{width:100%;padding:16px;border:none;border-radius:var(--radius);font-size:1rem;font-weight:600;cursor:pointer;margin-top:16px;transition:all .15s ease}.submit-btn{background:linear-gradient(135deg,var(--primary),#4a47a3);color:#fff}.submit-btn:disabled{opacity:.5;cursor:not-allowed}.submit-btn:not(:disabled):hover{transform:translateY(-1px);box-shadow:0 6px 20px #6c63ff66}.next-btn{background:var(--bg-card);color:var(--primary);border:2px solid var(--primary)}.explanation{margin-top:12px;padding:14px;background:#6c63ff14;border-radius:10px;font-size:.9rem;line-height:1.5;border-left:3px solid var(--primary)}.score-summary{text-align:center;padding:40px 20px}.score-summary .big-score{font-size:4rem;font-weight:700;background:linear-gradient(135deg,var(--primary),var(--accent));-webkit-background-clip:text;-webkit-text-fill-color:transparent}.score-summary .label{color:var(--text-muted);margin-top:8px}