/* ========== RESET & BASE ========== */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
    --bg-primary:#0a0e17;--bg-secondary:#111827;--bg-card:#1a2332;--bg-card-hover:#1e2a3a;
    --cyan:#00f0ff;--purple:#7b2fff;--green:#00ff88;--red:#ff3366;--yellow:#ffd700;--orange:#ff8c00;
    --text-primary:#e8eaed;--text-secondary:#8b95a5;--text-dim:#4a5568;
    --border:#1e2d3d;--glass:rgba(26,35,50,0.85);
    --font-mono:'JetBrains Mono',monospace;--font-sans:'Inter',sans-serif;
    --radius:12px;--radius-sm:8px;
}
html{scroll-behavior:smooth}
body{font-family:var(--font-sans);background:var(--bg-primary);color:var(--text-primary);min-height:100vh;overflow-x:hidden}
#matrix-bg{position:fixed;top:0;left:0;width:100%;height:100%;z-index:0;opacity:0.06;pointer-events:none}
#particles{position:fixed;top:0;left:0;width:100%;height:100%;z-index:0;pointer-events:none}
.screen{display:none;position:relative;z-index:1;min-height:100vh}
.screen.active{display:flex;flex-direction:column;animation:fadeIn .5s ease}
@keyframes fadeIn{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}

/* ========== GLASS CARD ========== */
.glass-card{background:var(--glass);backdrop-filter:blur(20px);border:1px solid var(--border);border-radius:var(--radius);padding:28px}

/* ========== LOGIN SCREEN ========== */
#login-screen{align-items:center;justify-content:center;padding:20px}
.login-container{max-width:480px;width:100%;text-align:center}
.logo-section{margin-bottom:32px}
.cyber-icon{margin-bottom:16px;animation:pulse 3s ease-in-out infinite}
@keyframes pulse{0%,100%{filter:drop-shadow(0 0 8px rgba(0,240,255,0.4))}50%{filter:drop-shadow(0 0 20px rgba(0,240,255,0.8))}}
.glitch-text{font-family:var(--font-mono);font-size:3rem;font-weight:900;background:linear-gradient(135deg,var(--cyan),var(--purple));-webkit-background-clip:text;-webkit-text-fill-color:transparent;letter-spacing:8px;position:relative}
.subtitle{color:var(--text-secondary);font-size:.95rem;margin-top:4px;letter-spacing:2px;text-transform:uppercase}
.terminal-line{font-family:var(--font-mono);font-size:.8rem;color:var(--green);margin-top:16px;display:flex;align-items:center;justify-content:center;gap:6px}
.prompt{color:var(--cyan)}
.cursor-blink{animation:blink 1s step-end infinite}
@keyframes blink{50%{opacity:0}}

.login-form{margin-top:24px;text-align:left}
.form-header{display:flex;align-items:center;gap:8px;margin-bottom:20px;font-size:.85rem;color:var(--text-secondary)}
.status-dot{width:8px;height:8px;border-radius:50%;background:var(--green);box-shadow:0 0 8px var(--green);animation:blink 2s ease-in-out infinite}

.input-group{margin-bottom:16px}
.input-group label{display:block;font-size:.8rem;color:var(--text-secondary);margin-bottom:6px;text-transform:uppercase;letter-spacing:1px}
.input-wrapper{display:flex;align-items:center;background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius-sm);overflow:hidden;transition:border-color .3s}
.input-wrapper:focus-within{border-color:var(--cyan);box-shadow:0 0 0 3px rgba(0,240,255,0.1)}
.input-icon{padding:0 12px;font-size:1.1rem}
.input-wrapper input{flex:1;background:none;border:none;color:var(--text-primary);font-size:.95rem;padding:14px 12px 14px 0;outline:none;font-family:var(--font-sans)}
.input-wrapper input::placeholder{color:var(--text-dim)}

/* ========== BUTTONS ========== */
.btn-primary{width:100%;padding:14px 24px;background:linear-gradient(135deg,var(--cyan),var(--purple));border:none;border-radius:var(--radius-sm);color:#fff;font-size:1rem;font-weight:600;cursor:pointer;display:flex;align-items:center;justify-content:center;gap:8px;transition:all .3s;position:relative;overflow:hidden}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 8px 25px rgba(0,240,255,0.3)}
.btn-primary:active{transform:translateY(0)}
.btn-secondary{padding:12px 24px;background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius-sm);color:var(--text-primary);font-size:.9rem;cursor:pointer;transition:all .3s}
.btn-secondary:hover{border-color:var(--cyan);background:var(--bg-card-hover)}
.btn-outline{padding:8px 16px;background:transparent;border:1px solid var(--border);border-radius:var(--radius-sm);color:var(--text-primary);font-size:.85rem;cursor:pointer;transition:all .3s}
.btn-outline:hover{border-color:var(--cyan);color:var(--cyan)}
.btn-danger{border-color:var(--red)!important;color:var(--red)!important}
.btn-danger:hover{background:rgba(255,51,102,0.1)!important}
.btn-back{padding:8px 16px;background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius-sm);color:var(--text-secondary);cursor:pointer;transition:all .3s;font-size:.85rem}
.btn-back:hover{border-color:var(--cyan);color:var(--cyan)}
.btn-finish{padding:14px 32px;background:linear-gradient(135deg,var(--green),#00cc6a);border:none;border-radius:var(--radius-sm);color:#000;font-size:1rem;font-weight:700;cursor:pointer;transition:all .3s}
.btn-finish:hover{transform:translateY(-2px);box-shadow:0 8px 25px rgba(0,255,136,0.3)}

.stats-bar{display:flex;justify-content:center;gap:40px;margin-top:32px}
.stat-item{text-align:center}
.stat-num{display:block;font-size:1.8rem;font-weight:800;background:linear-gradient(135deg,var(--cyan),var(--purple));-webkit-background-clip:text;-webkit-text-fill-color:transparent}
.stat-label{font-size:.75rem;color:var(--text-dim);text-transform:uppercase;letter-spacing:1px}

/* ========== TOP NAV ========== */
.top-nav{display:flex;align-items:center;justify-content:space-between;padding:12px 24px;background:rgba(10,14,23,0.9);backdrop-filter:blur(10px);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:10}
.nav-logo{font-family:var(--font-mono);font-weight:700;color:var(--cyan);font-size:1rem;letter-spacing:2px}
.nav-center{font-size:.9rem;color:var(--text-secondary)}
.nav-right{display:flex;gap:8px}

/* ========== CATEGORY GRID ========== */
.category-content{max-width:1200px;margin:0 auto;padding:24px}
.section-header{text-align:center;margin-bottom:32px}
.section-header h2{font-size:1.6rem;margin-bottom:8px}
.section-header p{color:var(--text-secondary);font-size:.9rem}
.category-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:16px}
.cat-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:20px;cursor:pointer;transition:all .3s;position:relative;overflow:hidden}
.cat-card::before{content:'';position:absolute;top:0;left:0;width:100%;height:3px;background:linear-gradient(90deg,var(--cyan),var(--purple));transform:scaleX(0);transform-origin:left;transition:transform .3s}
.cat-card:hover{border-color:var(--cyan);transform:translateY(-3px);box-shadow:0 8px 30px rgba(0,240,255,0.1)}
.cat-card:hover::before{transform:scaleX(1)}
.cat-icon{font-size:2rem;margin-bottom:10px}
.cat-title{font-size:1.05rem;font-weight:600;margin-bottom:4px}
.cat-desc{font-size:.8rem;color:var(--text-secondary);margin-bottom:12px;line-height:1.4}
.cat-meta{display:flex;justify-content:space-between;align-items:center}
.cat-count{font-size:.75rem;color:var(--cyan);font-family:var(--font-mono);background:rgba(0,240,255,0.1);padding:4px 10px;border-radius:20px}
.cat-diff{font-size:.7rem;padding:4px 10px;border-radius:20px;font-weight:600;text-transform:uppercase;letter-spacing:.5px}
.diff-easy{background:rgba(0,255,136,0.15);color:var(--green)}
.diff-medium{background:rgba(255,200,0,0.15);color:var(--yellow)}
.diff-hard{background:rgba(255,51,102,0.15);color:var(--red)}

/* ========== EXAM SCREEN ========== */
.exam-header{position:sticky;top:0;z-index:10;background:rgba(10,14,23,0.95);backdrop-filter:blur(10px);border-bottom:1px solid var(--border);padding:12px 24px}
.exam-nav{display:flex;align-items:center;justify-content:space-between;margin-bottom:12px}
.exam-nav h3{font-size:1rem;color:var(--text-primary)}
.exam-timer{display:flex;align-items:center;gap:6px;font-family:var(--font-mono);font-size:1.1rem;color:var(--cyan);background:rgba(0,240,255,0.08);padding:6px 14px;border-radius:var(--radius-sm);border:1px solid rgba(0,240,255,0.2)}
.progress-container{position:relative;height:6px;background:var(--bg-secondary);border-radius:3px;overflow:hidden}
.progress-bar{height:100%;background:linear-gradient(90deg,var(--cyan),var(--purple));border-radius:3px;transition:width .4s ease;width:0}
.progress-text{position:absolute;right:0;top:-20px;font-size:.75rem;color:var(--text-secondary);font-family:var(--font-mono)}

.exam-body{max-width:800px;margin:24px auto;padding:0 24px}
.question-card{margin-bottom:20px;min-height:300px}
.q-number{font-family:var(--font-mono);font-size:.8rem;color:var(--cyan);margin-bottom:8px;display:flex;align-items:center;gap:8px}
.q-type-badge{font-size:.65rem;padding:2px 8px;border-radius:10px;background:rgba(123,47,255,0.15);color:var(--purple);text-transform:uppercase;letter-spacing:.5px}
.q-text{font-size:1.1rem;font-weight:500;line-height:1.6;margin-bottom:20px}
.q-text code{font-family:var(--font-mono);background:rgba(0,240,255,0.08);padding:2px 6px;border-radius:4px;color:var(--cyan);font-size:.9rem}
.q-hint{font-size:.8rem;color:var(--text-dim);font-style:italic;margin-bottom:16px;padding:8px 12px;border-left:3px solid var(--purple);background:rgba(123,47,255,0.05)}

/* MCQ Options */
.options-list{display:flex;flex-direction:column;gap:10px}
.option-btn{display:flex;align-items:center;gap:12px;padding:14px 16px;background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius-sm);cursor:pointer;transition:all .25s;text-align:left;font-size:.95rem;color:var(--text-primary);width:100%}
.option-btn:hover{border-color:var(--cyan);background:rgba(0,240,255,0.05)}
.option-btn.selected{border-color:var(--cyan);background:rgba(0,240,255,0.1);box-shadow:0 0 0 2px rgba(0,240,255,0.15)}
.option-btn.correct{border-color:var(--green)!important;background:rgba(0,255,136,0.1)!important}
.option-btn.wrong{border-color:var(--red)!important;background:rgba(255,51,102,0.1)!important}
.option-letter{width:28px;height:28px;border-radius:50%;background:var(--bg-card);display:flex;align-items:center;justify-content:center;font-weight:600;font-size:.85rem;flex-shrink:0;border:1px solid var(--border);transition:all .25s}
.option-btn.selected .option-letter{background:var(--cyan);color:#000;border-color:var(--cyan)}
.option-btn.correct .option-letter{background:var(--green);color:#000;border-color:var(--green)}
.option-btn.wrong .option-letter{background:var(--red);color:#fff;border-color:var(--red)}

/* Fill-in-blank */
.fill-input{width:100%;padding:14px 16px;background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius-sm);color:var(--text-primary);font-family:var(--font-mono);font-size:1rem;outline:none;transition:border-color .3s}
.fill-input:focus{border-color:var(--cyan);box-shadow:0 0 0 3px rgba(0,240,255,0.1)}
.fill-input.correct{border-color:var(--green);box-shadow:0 0 0 3px rgba(0,255,136,0.1)}
.fill-input.wrong{border-color:var(--red);box-shadow:0 0 0 3px rgba(255,51,102,0.1)}

/* True/False */
.tf-options{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.tf-btn{padding:16px;text-align:center;background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius-sm);cursor:pointer;font-weight:600;font-size:1rem;transition:all .25s}
.tf-btn:hover{border-color:var(--cyan)}
.tf-btn.selected{border-color:var(--cyan);background:rgba(0,240,255,0.1)}
.tf-btn.correct{border-color:var(--green)!important;background:rgba(0,255,136,0.1)!important}
.tf-btn.wrong{border-color:var(--red)!important;background:rgba(255,51,102,0.1)!important}

/* Code block in question */
.code-block{background:#0d1117;border:1px solid #21262d;border-radius:var(--radius-sm);padding:14px 16px;font-family:var(--font-mono);font-size:.85rem;color:#c9d1d9;margin:12px 0;overflow-x:auto;line-height:1.6;white-space:pre-wrap}

.exam-controls{display:flex;justify-content:center;gap:12px;padding:20px 0}

/* ========== RESULT SCREEN ========== */
#result-screen{padding:24px}
.result-container{max-width:700px;margin:0 auto}
.result-header{text-align:center;margin-bottom:24px;padding:32px}
.result-icon{font-size:4rem;margin-bottom:12px}
.result-header h2{font-size:1.6rem;margin-bottom:20px}
.score-circle{position:relative;width:140px;height:140px;margin:0 auto 24px}
.score-circle svg{width:100%;height:100%}
#score-ring{transition:stroke-dashoffset 1.5s ease}
.score-percent{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);font-size:1.8rem;font-weight:800;font-family:var(--font-mono);background:linear-gradient(135deg,var(--cyan),var(--purple));-webkit-background-clip:text;-webkit-text-fill-color:transparent}
.result-stats{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-bottom:20px}
.r-stat{text-align:center;padding:12px;background:var(--bg-secondary);border-radius:var(--radius-sm)}
.r-stat span{display:block;font-size:1.6rem;font-weight:700;font-family:var(--font-mono)}
.r-stat label{font-size:.7rem;color:var(--text-secondary);text-transform:uppercase;letter-spacing:1px}
.r-stat.correct span{color:var(--green)}
.r-stat.wrong span{color:var(--red)}
.r-stat.skip span{color:var(--yellow)}
.r-stat.total span{color:var(--cyan)}
.student-info-result{font-size:.85rem;color:var(--text-secondary);padding-top:12px;border-top:1px solid var(--border)}

.result-details{margin-bottom:24px}
.rd-item{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius-sm);padding:14px;margin-bottom:8px;font-size:.88rem}
.rd-item.rd-correct{border-left:3px solid var(--green)}
.rd-item.rd-wrong{border-left:3px solid var(--red)}
.rd-item.rd-skip{border-left:3px solid var(--yellow)}
.rd-q{font-weight:500;margin-bottom:6px}
.rd-answer{font-family:var(--font-mono);font-size:.8rem;color:var(--text-secondary)}
.rd-answer .correct-ans{color:var(--green)}
.rd-answer .your-ans{color:var(--red)}

.result-actions{display:flex;gap:12px;justify-content:center}
.result-actions .btn-primary,.result-actions .btn-secondary{width:auto;padding:12px 24px}

/* ========== RESPONSIVE ========== */
@media(max-width:768px){
    .glitch-text{font-size:2rem;letter-spacing:4px}
    .category-grid{grid-template-columns:1fr}
    .stats-bar{gap:20px}
    .stat-num{font-size:1.4rem}
    .top-nav{flex-direction:column;gap:8px;text-align:center}
    .nav-right{justify-content:center}
    .exam-body{padding:0 12px}
    .result-stats{grid-template-columns:repeat(2,1fr)}
    .tf-options{grid-template-columns:1fr}
    .exam-nav{flex-wrap:wrap;gap:8px}
}

/* ========== PRINT ========== */
@media print{
    #matrix-bg,#particles,.top-nav,.exam-controls,.result-actions,.btn-back{display:none!important}
    body{background:#fff;color:#000}
    .glass-card,.result-header{background:#fff;border:1px solid #ccc}
    .screen{display:block!important}
    .r-stat span{-webkit-text-fill-color:initial}
}