:root{--color-primary: #F27733;--color-primary-dark: #E06622;--color-primary-light: #FFF3EC;--color-bg: #FFFFFF;--color-surface: #F8F8F8;--color-text: #1A1A1A;--color-text-muted: #6B6B6B;--color-text-light: #999999;--color-border: #E5E5E5;--color-border-light: #F0F0F0;--color-danger: #E53E3E;--color-success: #2E7D32;--space-1: 4px;--space-2: 8px;--space-3: 12px;--space-4: 16px;--space-5: 20px;--space-6: 24px;--space-7: 32px;--space-8: 48px;--radius-sm: 6px;--radius-md: 10px;--radius-lg: 16px;--font-stack: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif}*{box-sizing:border-box;margin:0;padding:0}[hidden]{display:none!important}html,body{font-family:var(--font-stack);color:var(--color-text);background:var(--color-bg);-webkit-font-smoothing:antialiased;min-height:100vh;font-size:16px;line-height:1.5;font-weight:400}#app{max-width:560px;margin:0 auto;min-height:100vh;display:flex;flex-direction:column;background:var(--color-bg)}button{font-family:inherit;cursor:pointer;border:none;font-weight:600;transition:background .2s ease,transform .1s ease,opacity .2s ease;-webkit-appearance:none;appearance:none}button:active{transform:scale(.98)}button:disabled{opacity:.5;cursor:not-allowed}.app-header{background:var(--color-primary);color:#fff;padding:var(--space-5) var(--space-6) var(--space-5);text-align:center;position:relative}.app-header--compact{padding:var(--space-4) var(--space-5) var(--space-4)}.app-header__back{position:absolute;left:var(--space-4);top:50%;transform:translateY(-50%);background:transparent;color:#fff;font-size:28px;font-weight:400;padding:4px 10px;line-height:1;width:auto;border-radius:0}.app-header__back:hover{background:#ffffff26}.app-header__inner{padding:0 var(--space-8)}.app-header__title{font-size:22px;font-weight:700;color:#fff;margin:0;line-height:1.3}.app-header__subtitle{font-size:13px;color:#ffffffd9;margin-top:4px;font-weight:400}.page{flex:1;padding:var(--space-6) var(--space-5);display:flex;flex-direction:column;gap:var(--space-6)}.btn-primary{background:var(--color-primary);color:#fff;border-radius:var(--radius-md);padding:var(--space-4) var(--space-6);font-size:16px;font-weight:600;text-align:center;display:inline-block;width:auto;border:none;text-decoration:none;line-height:1.4}.btn-primary:hover{background:var(--color-primary-dark)}.btn-primary:disabled{opacity:.5;cursor:not-allowed}.btn-large{width:100%;padding:var(--space-4) var(--space-6);font-size:16px;border-radius:var(--radius-md)}.btn-block{display:block;width:100%}.btn-link{background:transparent;color:var(--color-primary);font-size:15px;font-weight:600;padding:var(--space-3) var(--space-4);text-decoration:none;border:none;cursor:pointer}.btn-link:hover{color:var(--color-primary-dark);text-decoration:underline}.info-block{display:flex;flex-direction:column;gap:var(--space-3)}.info-block__line{font-size:15px;color:var(--color-text);line-height:1.6;font-weight:400!important}.info-block__label{font-weight:400!important;display:inline}.info-block__line strong{font-weight:400!important}.info-block--bottom{margin-top:auto}.cta-area{display:flex;flex-direction:column;align-items:center;gap:var(--space-3)}.cta-hint{font-size:13px;color:var(--color-text-light)}.select-area{display:flex;justify-content:flex-end;margin-bottom:var(--space-4)}.select-area .btn-large{width:auto;min-width:260px}.file-list{list-style:none;display:flex;flex-direction:column}.file-item{display:flex;align-items:center;gap:var(--space-3);padding:var(--space-4) 0;border-bottom:1px solid var(--color-border-light)}.file-item:last-child{border-bottom:none}.file-item__icon{flex-shrink:0;width:32px;height:32px;display:flex;align-items:center;justify-content:center}.file-item__icon svg{display:block}.file-item__name{flex:1;font-size:15px;color:var(--color-text);overflow:hidden;text-overflow:ellipsis;white-space:nowrap;min-width:0}.file-item__remove{flex-shrink:0;background:transparent;color:var(--color-primary);border:1px solid var(--color-primary);border-radius:var(--radius-sm);padding:6px 14px;font-size:13px;font-weight:600;cursor:pointer;transition:background .2s ease,color .2s ease;white-space:nowrap}.file-item__remove:hover{background:var(--color-primary);color:#fff}.merge-area{margin-top:auto;padding-top:var(--space-5)}.error-text{color:var(--color-danger);font-size:14px;margin:var(--space-2) 0;padding:var(--space-2) var(--space-3);background:#fff0f0;border-radius:var(--radius-sm)}.loading-overlay{position:fixed;inset:0;background:#ffffffe6;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:var(--space-3);z-index:100}.loading-spinner{width:40px;height:40px;border:3px solid var(--color-border);border-top-color:var(--color-primary);border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.loading-text{font-size:14px;color:var(--color-text-muted)}.success-section{display:flex;flex-direction:column;align-items:center;gap:var(--space-3);padding:var(--space-5) 0}.success-check{width:64px;height:64px;display:flex;align-items:center;justify-content:center}.success-title{font-size:22px;font-weight:700;color:var(--color-success);margin:0}.success-desc{font-size:14px;color:var(--color-text-muted);margin:0}.file-info{display:flex;flex-direction:column;border:1px solid var(--color-border);border-radius:var(--radius-md);overflow:hidden}.file-info__row{display:flex;justify-content:space-between;align-items:center;padding:var(--space-3) var(--space-4);border-bottom:1px solid var(--color-border-light);gap:var(--space-4)}.file-info__row:last-child{border-bottom:none}.file-info__label{font-size:14px;color:var(--color-text-muted);font-weight:500}.file-info__value{font-size:14px;color:var(--color-text);font-weight:600;text-align:right;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;max-width:60%}.download-area{padding:var(--space-2) 0}.download-btn{text-decoration:none;display:block;text-align:center}.restart-area{display:flex;justify-content:center;padding:var(--space-2) 0}.empty-state{display:flex;flex-direction:column;align-items:center;gap:var(--space-4);padding:var(--space-7) 0;text-align:center}.empty-state h2{font-size:20px;color:var(--color-text)}.empty-state p{font-size:14px;color:var(--color-text-muted)}@media (max-width: 480px){#app{max-width:100%}.app-header{padding:var(--space-4) var(--space-4) var(--space-4)}.app-header--compact{padding:var(--space-3) var(--space-4)}.page{padding:var(--space-4)}.select-area .btn-large{width:100%;min-width:0}.file-item__name{font-size:14px}.file-item__remove{padding:5px 10px;font-size:12px}}