:root{--primary: #6366f1;--primary-dark: #4f46e5;--primary-light: #818cf8;--success: #10b981;--success-dark: #059669;--text: #1f2937;--text-light: #6b7280;--bg: #ffffff;--bg-secondary: #f9fafb;--border: #e5e7eb;--shadow: rgba(0, 0, 0, 0.1);--shadow-lg: rgba(0, 0, 0, 0.15);--bg-gradient-start: #667eea;--bg-gradient-end: #764ba2;--cancel: #dc2626;--faq-bg: white;--faq-item-bg: white;--faq-item-hover-bg: #fafbfc;--faq-item-border: #f3f4f6;--header-text: white;--primary-hover-bg: rgba(99, 102, 241, 0.1)}[data-theme=dark]{--primary: #818cf8;--primary-dark: #6366f1;--primary-light: #a5b4fc;--success: #34d399;--success-dark: #10b981;--text: #f9fafb;--text-light: #9ca3af;--bg: #111827;--bg-secondary: #1f2937;--border: #374151;--shadow: rgba(0, 0, 0, 0.3);--shadow-lg: rgba(0, 0, 0, 0.5);--bg-gradient-start: #1e1b4b;--bg-gradient-end: #312e81;--cancel: #ef4444;--faq-bg: #1f2937;--faq-item-bg: #1f2937;--faq-item-hover-bg: #283548;--faq-item-border: #374151;--header-text: white;--primary-hover-bg: rgba(129, 140, 248, 0.15)}*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;line-height:1.6;color:var(--text);background:linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);min-height:100vh;padding:20px}.container{max-width:900px;margin:0 auto}.header{text-align:center;margin-bottom:40px;color:var(--header-text);position:relative}.logo{display:flex;align-items:center;justify-content:center;gap:15px;margin-bottom:10px}.logo-icon{width:48px;height:48px;color:var(--header-text)}.logo h1{font-size:3rem;font-weight:800;letter-spacing:-1px}.tagline{font-size:1.25rem;opacity:.95;font-weight:300}.main{background:var(--bg);border-radius:16px;box-shadow:0 20px 60px var(--shadow-lg);padding:40px;min-height:500px}.upload-section{text-align:center}.upload-box{border:3px dashed var(--border);border-radius:12px;padding:60px 40px;transition:all .3s ease;cursor:pointer}.upload-box:hover,.upload-box.drag-over{border-color:var(--primary);background:var(--bg-secondary)}.upload-icon{width:64px;height:64px;color:var(--primary);margin-bottom:20px}.upload-box h2{font-size:1.75rem;margin-bottom:10px;color:var(--text)}.upload-box p{color:var(--text-light);margin-bottom:20px}.select-btn{background:var(--primary);color:#fff;border:none;padding:14px 32px;font-size:1rem;font-weight:600;border-radius:8px;cursor:pointer;transition:all .2s;margin-bottom:20px}.select-btn:hover{background:var(--primary-dark);transform:translateY(-2px);box-shadow:0 4px 12px var(--shadow)}.privacy-note{font-size:.9rem;color:var(--success);font-weight:500;margin-top:20px}.converter-section{animation:fadeIn .4s ease}@keyframes fadeIn{from{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}.file-info{display:grid;grid-template-columns:1fr 1fr;gap:30px;margin-bottom:40px;padding-bottom:30px;border-bottom:2px solid var(--border)}.file-preview.hidden+.file-details{grid-column:1/-1}.file-preview video{width:100%;border-radius:8px;background:#000;max-height:250px}.file-details{display:flex;flex-direction:column;justify-content:center}.file-details h3{font-size:1.25rem;margin-bottom:10px;word-break:break-word}.file-details p{color:var(--text-light);margin-bottom:8px}.change-file-btn{margin-top:20px;background:var(--bg-secondary);color:var(--text);border:2px solid var(--border);padding:10px 20px;border-radius:8px;cursor:pointer;font-weight:600;transition:all .2s}.change-file-btn:hover{border-color:var(--primary);color:var(--primary)}.format-selector{margin-bottom:30px}.format-selector h3{font-size:1.25rem;margin-bottom:15px;color:var(--text)}.format-label{font-size:.85rem;font-weight:600;color:var(--text-light);text-transform:uppercase;letter-spacing:.05em;margin-bottom:8px;margin-top:16px}.format-label:first-of-type{margin-top:0}.format-grid{display:grid;grid-template-columns:repeat(4, 1fr);gap:10px;margin-bottom:12px}.format-btn{background:var(--bg-secondary);border:2px solid var(--border);color:var(--text);padding:12px 8px;border-radius:8px;font-size:.95rem;font-weight:600;cursor:pointer;transition:all .2s;text-transform:uppercase;text-align:center}.format-btn:hover{border-color:var(--primary-light);background:var(--primary-hover-bg)}.format-btn.selected{background:var(--primary);color:#fff;border-color:var(--primary)}.resolution-options,.quality-options{margin-bottom:30px}.resolution-options h3,.quality-options h3{font-size:1.25rem;margin-bottom:15px;color:var(--text)}.resolution-controls,.quality-controls{display:grid;grid-template-columns:repeat(4, 1fr);gap:10px}.option-btn{background:var(--bg-secondary);border:2px solid var(--border);color:var(--text);padding:12px 8px;border-radius:8px;font-size:.95rem;font-weight:600;cursor:pointer;transition:all .2s;text-align:center}.option-btn:hover{border-color:var(--primary-light);background:var(--primary-hover-bg)}.option-btn.selected{background:var(--primary);color:#fff;border-color:var(--primary)}.option-btn.selected small{color:hsla(0,0%,100%,.8)}.option-btn small{display:block;font-size:.75rem;font-weight:400;color:var(--text-light);margin-top:4px}.convert-btn{width:100%;background:var(--primary);color:#fff;border:none;padding:16px 32px;font-size:1.125rem;font-weight:700;border-radius:8px;cursor:pointer;transition:all .2s;margin-bottom:20px}.convert-btn:hover{background:var(--primary-dark);transform:translateY(-2px);box-shadow:0 6px 20px var(--shadow)}.convert-btn:active{transform:translateY(0)}.convert-btn:disabled{background:var(--text-light);cursor:not-allowed;transform:none;box-shadow:none}.progress-section{margin:30px 0;text-align:center}.progress-bar{width:100%;height:12px;background:var(--bg-secondary);border-radius:6px;overflow:hidden;margin-bottom:15px}.progress-fill{height:100%;background:linear-gradient(90deg, var(--primary), var(--primary-light));border-radius:6px;transition:width .3s ease;width:0%}.progress-text{color:var(--text-light);font-weight:600;font-size:1.125rem}.time-remaining{color:var(--text-light);font-size:.95rem;margin-top:8px}.cancel-btn{margin-top:20px;background:rgba(0,0,0,0);color:var(--cancel);border:2px solid var(--cancel);padding:10px 24px;border-radius:8px;cursor:pointer;font-weight:600;transition:all .2s}.cancel-btn:hover{background:var(--cancel);color:#fff}.download-section{text-align:center;padding:40px 0}.download-section .download-actions{display:flex;justify-content:center;align-items:center;gap:12px;flex-wrap:wrap}.success-icon{width:80px;height:80px;background:var(--success);color:#fff;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:3rem;margin:0 auto 20px;animation:scaleIn .4s ease}@keyframes scaleIn{from{transform:scale(0)}to{transform:scale(1)}}.download-section h3{font-size:1.75rem;margin-bottom:25px;color:var(--text)}.download-btn{background:var(--success);color:#fff;border:none;padding:16px 40px;font-size:1.125rem;font-weight:700;border-radius:8px;cursor:pointer;transition:all .2s}.download-btn:hover{background:var(--success-dark);transform:translateY(-2px);box-shadow:0 6px 20px var(--shadow)}.convert-another-btn{background:rgba(0,0,0,0);color:var(--primary);border:2px solid var(--primary);padding:12px 32px;font-size:1rem;font-weight:600;border-radius:8px;cursor:pointer;transition:all .2s}.convert-another-btn:hover{background:var(--primary);color:#fff}.hidden{display:none !important}.features-bar{margin-top:40px;color:var(--header-text);text-align:center}.features{display:flex;justify-content:center;gap:30px;flex-wrap:wrap;margin-bottom:20px}.feature{display:flex;align-items:center;gap:8px;font-weight:500;font-size:1rem}.feature-icon{font-size:1.5rem}.copyright{opacity:.8;font-size:.9rem}.copyright a{color:var(--header-text);text-decoration:none;border-bottom:1px solid hsla(0,0%,100%,.5);transition:border-color .2s}.copyright a:hover{border-bottom-color:#fff}.faq-section{margin-top:40px;margin-bottom:40px}.footer{text-align:center;padding:0 20px 40px;color:var(--header-text)}.footer p{opacity:.8;font-size:.9rem;margin:0}.footer a{color:var(--header-text);text-decoration:none;border-bottom:1px solid hsla(0,0%,100%,.5);transition:border-color .2s}.footer a:hover{border-bottom-color:#fff}.faq-container{max-width:900px;margin:0 auto;background:var(--faq-bg);border-radius:20px;padding:60px 50px;box-shadow:0 25px 70px var(--shadow-lg)}.faq-container h2{text-align:center;font-size:1.75rem;margin-bottom:60px;color:var(--text);font-weight:800;letter-spacing:-0.5px}.faq-item{margin-bottom:24px;padding:28px 32px;border-radius:12px;background:var(--faq-item-bg);transition:all .3s ease;border:2px solid var(--faq-item-border)}.faq-item:last-child{margin-bottom:0}.faq-item:hover{background:var(--faq-item-hover-bg);border-color:var(--primary-light);transform:translateY(-2px);box-shadow:0 8px 20px var(--shadow)}.faq-item summary{font-size:1.2rem;color:var(--text);font-weight:700;line-height:1.4;cursor:pointer;list-style:none;display:flex;align-items:baseline}.faq-item summary::-webkit-details-marker{display:none}.faq-item summary::before{content:"+";color:var(--primary);font-size:1.4rem;font-weight:700;margin-right:12px;flex-shrink:0;width:.75em;text-align:center;line-height:1;position:relative;top:-0.05em}.faq-item[open] summary::before{content:"-"}.faq-item[open]>div{margin-top:14px}.faq-item p{color:var(--text-light);line-height:1.75;font-size:1rem;margin:0;padding-left:24px}.faq-item p a{color:var(--primary);text-decoration:none;font-weight:500;border-bottom:1px solid rgba(0,0,0,0);transition:border-color .2s}.faq-item p a:hover{border-bottom-color:var(--primary)}.about-section{margin-top:40px;margin-bottom:40px}.about-container{max-width:900px;margin:0 auto;background:var(--faq-bg);border-radius:20px;padding:60px 50px;box-shadow:0 25px 70px var(--shadow-lg)}.about-container h2{font-size:1.75rem;margin-bottom:20px;color:var(--text);font-weight:800;letter-spacing:-0.5px}.about-container h3{font-size:1.25rem;margin-top:32px;margin-bottom:16px;color:var(--text);font-weight:700}.about-container>p{color:var(--text-light);line-height:1.75;font-size:1rem}.about-tools{display:grid;grid-template-columns:1fr 1fr;gap:16px}.about-tool{display:block;padding:24px;border-radius:12px;border:2px solid var(--faq-item-border);background:var(--faq-item-bg);text-decoration:none;transition:all .3s ease}.about-tool:hover{border-color:var(--primary-light);transform:translateY(-2px);box-shadow:0 8px 20px var(--shadow)}.about-tool strong{display:block;font-size:1.1rem;color:var(--primary);margin-bottom:8px}.about-tool span{color:var(--text-light);font-size:.95rem;line-height:1.6}.theme-toggle{position:absolute;top:0;right:0;background:hsla(0,0%,100%,.15);border:1px solid hsla(0,0%,100%,.25);color:var(--header-text);width:40px;height:40px;border-radius:10px;cursor:pointer;display:flex;align-items:center;justify-content:center;transition:background .2s;backdrop-filter:blur(8px)}.theme-toggle svg{width:20px;height:20px}.theme-toggle:hover{background:hsla(0,0%,100%,.25)}@media(max-width: 768px){.header{margin-bottom:24px}.logo h1{font-size:2rem}.main{padding:24px 20px}.upload-box{padding:40px 24px}.file-info{grid-template-columns:1fr;gap:20px}.format-grid{grid-template-columns:repeat(3, 1fr);gap:8px}.resolution-controls,.quality-controls{grid-template-columns:repeat(3, 1fr);gap:8px}.features-bar{margin-top:24px}.features{gap:16px}.feature{font-size:.9rem}.faq-section{margin-top:24px;margin-bottom:24px}.faq-container{padding:32px 20px;border-radius:16px}.faq-container h2{font-size:1.5rem;margin-bottom:28px}.faq-item{padding:20px 16px;margin-bottom:12px}.faq-item summary{font-size:1.05rem}.faq-item p{font-size:.95rem;padding-left:20px;line-height:1.65}.about-section{margin-top:24px;margin-bottom:24px}.about-container{padding:32px 20px;border-radius:16px}.about-container h2{font-size:1.5rem}.about-tools{grid-template-columns:1fr}.about-tool{padding:20px 16px}.footer{padding-bottom:24px}}@media(max-width: 480px){body{padding:10px}.header{margin-bottom:16px}.logo h1{font-size:1.75rem}.tagline{font-size:1rem}.upload-box{padding:32px 16px}.format-grid,.resolution-controls,.quality-controls{grid-template-columns:repeat(2, 1fr)}}