*{margin:0;padding:0;box-sizing:border-box}
:root{--bg:#0f0f1a;--card:#1a1a2e;--card2:#16213e;--primary:#6c63ff;--primary-light:#8b83ff;--accent:#00d4aa;--danger:#ff4757;--success:#2ed573;--text:#e8e8f0;--text2:#a0a0b8;--radius:16px;--shadow:0 8px 32px rgba(0,0,0,0.3)}
body{font-family:'Inter',sans-serif;background:var(--bg);color:var(--text);min-height:100vh;overflow-x:hidden}
.screen{display:none;min-height:100vh;animation:fadeIn .4s ease}
.screen.active{display:flex;flex-direction:column}
@keyframes fadeIn{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}
@keyframes pulse{0%,100%{transform:scale(1)}50%{transform:scale(1.05)}}
@keyframes slideUp{from{opacity:0;transform:translateY(30px)}to{opacity:1;transform:translateY(0)}}
@keyframes shake{0%,100%{transform:translateX(0)}25%{transform:translateX(-5px)}75%{transform:translateX(5px)}}

/* Start Screen */
.start-container{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:24px;text-align:center}
.logo-icon{font-size:72px;margin-bottom:16px;animation:pulse 2s infinite}
.start-container h1{font-size:32px;font-weight:800;background:linear-gradient(135deg,var(--primary),var(--accent));-webkit-background-clip:text;-webkit-text-fill-color:transparent;margin-bottom:8px}
.subtitle{color:var(--text2);font-size:16px;margin-bottom:32px}
.sections-preview{width:100%;max-width:400px;margin-bottom:32px}
.section-item{background:var(--card);border-radius:12px;padding:12px 16px;margin-bottom:8px;display:flex;justify-content:space-between;align-items:center;font-size:14px;border:1px solid rgba(108,99,255,0.15)}
.section-item span:last-child{color:var(--primary-light);font-weight:600}

/* Buttons */
.btn-primary{background:linear-gradient(135deg,var(--primary),#5a52d5);color:#fff;border:none;padding:16px 48px;border-radius:50px;font-size:17px;font-weight:700;cursor:pointer;transition:all .3s;box-shadow:0 4px 20px rgba(108,99,255,0.4);font-family:inherit;width:100%;max-width:400px}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 6px 28px rgba(108,99,255,0.5)}
.btn-primary:active{transform:scale(.97)}
.btn-secondary{background:transparent;color:var(--primary-light);border:2px solid var(--primary);padding:14px 48px;border-radius:50px;font-size:16px;font-weight:600;cursor:pointer;transition:all .3s;margin-top:12px;font-family:inherit;width:100%;max-width:400px}
.btn-secondary:hover{background:rgba(108,99,255,0.1)}

/* Quiz Header */
.quiz-header{position:sticky;top:0;background:rgba(15,15,26,0.95);backdrop-filter:blur(10px);padding:16px 20px 12px;z-index:10;border-bottom:1px solid rgba(255,255,255,0.05)}
.progress-info{display:flex;justify-content:space-between;font-size:13px;color:var(--text2);margin-bottom:8px}
.progress-bar{height:6px;background:rgba(255,255,255,0.08);border-radius:3px;overflow:hidden}
.progress-fill{height:100%;background:linear-gradient(90deg,var(--primary),var(--accent));border-radius:3px;transition:width .4s ease}
.score-live{text-align:right;font-size:13px;color:var(--accent);font-weight:600;margin-top:6px}

/* Quiz Body */
.quiz-body{flex:1;padding:20px;max-width:600px;margin:0 auto;width:100%}
.question-card{background:var(--card);border-radius:var(--radius);padding:24px 20px;margin-bottom:16px;box-shadow:var(--shadow);animation:slideUp .3s ease;border:1px solid rgba(255,255,255,0.05)}
.question-text{font-size:17px;font-weight:600;line-height:1.6;margin-bottom:20px;white-space:pre-line}
.options{display:flex;flex-direction:column;gap:10px}
.option-btn{display:flex;align-items:flex-start;gap:12px;background:rgba(255,255,255,0.04);border:2px solid rgba(255,255,255,0.08);border-radius:12px;padding:14px 16px;cursor:pointer;transition:all .25s;text-align:left;font-size:15px;line-height:1.5;color:var(--text);font-family:inherit;width:100%}
.option-btn:hover{border-color:var(--primary);background:rgba(108,99,255,0.08)}
.option-btn:active{transform:scale(.98)}
.option-letter{min-width:32px;height:32px;border-radius:50%;background:rgba(108,99,255,0.15);display:flex;align-items:center;justify-content:center;font-weight:700;font-size:14px;color:var(--primary-light);flex-shrink:0}
.option-text{padding-top:4px;flex:1;word-break:break-word}
.option-btn.selected{border-color:var(--primary);background:rgba(108,99,255,0.15)}
.option-btn.selected .option-letter{background:var(--primary);color:#fff}
.option-btn.correct{border-color:var(--success)!important;background:rgba(46,213,115,0.12)!important;animation:none}
.option-btn.correct .option-letter{background:var(--success)!important;color:#fff!important}
.option-btn.wrong{border-color:var(--danger)!important;background:rgba(255,71,87,0.12)!important;animation:shake .4s ease}
.option-btn.wrong .option-letter{background:var(--danger)!important;color:#fff!important}
.option-btn.disabled{pointer-events:none;opacity:.85}

/* Navigation */
.quiz-nav{display:flex;gap:12px;padding-bottom:20px}
.btn-nav{flex:1;padding:14px;border-radius:12px;border:none;font-size:15px;font-weight:600;cursor:pointer;transition:all .2s;font-family:inherit;background:var(--card);color:var(--text2);border:1px solid rgba(255,255,255,0.08)}
.btn-nav:hover{background:var(--card2)}
.btn-nav:disabled{opacity:.3;cursor:not-allowed}
.btn-next{background:var(--primary)!important;color:#fff!important;border:none!important}
.btn-next:hover{background:var(--primary-light)!important}

/* Results */
.result-container{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:24px;text-align:center;animation:slideUp .5s ease}
.result-icon{font-size:64px;margin-bottom:16px}
.result-container h2{font-size:24px;font-weight:700;margin-bottom:20px}
.result-score{font-size:64px;font-weight:800;background:linear-gradient(135deg,var(--primary),var(--accent));-webkit-background-clip:text;-webkit-text-fill-color:transparent;margin-bottom:8px}
.result-detail{color:var(--text2);font-size:15px;margin-bottom:24px}
.result-bar{width:100%;max-width:300px;height:10px;background:rgba(255,255,255,0.08);border-radius:5px;overflow:hidden;margin-bottom:32px}
.result-bar-fill{height:100%;border-radius:5px;transition:width 1s ease}
.final-sections{width:100%;max-width:400px;margin-bottom:24px}
.final-section-row{display:flex;justify-content:space-between;align-items:center;padding:10px 16px;background:var(--card);border-radius:10px;margin-bottom:6px;font-size:14px}
.final-section-row .s-score{font-weight:700}
.s-score.good{color:var(--success)}
.s-score.mid{color:#ffa502}
.s-score.bad{color:var(--danger)}

/* Review */
.review-header{position:sticky;top:0;background:rgba(15,15,26,0.95);backdrop-filter:blur(10px);padding:16px 20px;display:flex;align-items:center;gap:16px;z-index:10;border-bottom:1px solid rgba(255,255,255,0.05)}
.review-header h2{flex:1;font-size:18px}
.btn-back{background:none;border:none;color:var(--primary-light);font-size:15px;cursor:pointer;font-family:inherit;font-weight:600}
.review-body{padding:20px;max-width:600px;margin:0 auto;width:100%}
.review-card{background:var(--card);border-radius:var(--radius);padding:20px;margin-bottom:16px;border-left:4px solid var(--danger)}
.review-card .r-question{font-size:15px;font-weight:600;margin-bottom:12px;line-height:1.5}
.review-card .r-your{color:var(--danger);font-size:14px;margin-bottom:4px;padding:8px 12px;background:rgba(255,71,87,0.1);border-radius:8px}
.review-card .r-correct{color:var(--success);font-size:14px;padding:8px 12px;background:rgba(46,213,115,0.1);border-radius:8px}

@media(max-width:480px){
    .start-container h1{font-size:26px}
    .logo-icon{font-size:56px}
    .question-text{font-size:15px}
    .option-btn{padding:12px 14px;font-size:14px}
    .result-score{font-size:48px}
    .btn-primary{padding:14px 32px;font-size:16px}
}