:root{--text-primary:#1d1d1f;--text-secondary:#86868b;--text-tertiary:#6e6e73;--bg-primary:#fff;--bg-secondary:#f5f5f7;--bg-tertiary:#fbfbfd;--border:#00000014;--border-strong:#0000001f;--accent:#0071e3;--accent-hover:#0077ed;--success:#34c759;--warning:#ff9f0a;--error:#ff3b30;--shadow-sm:0 1px 3px #00000014;--shadow-md:0 4px 12px #00000014;--shadow-lg:0 8px 24px #0000001f;--font-system:-apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", "Helvetica", "Arial", sans-serif;--font-mono:"SF Mono", ui-monospace, "Menlo", "Monaco", "Cascadia Mono", "Segoe UI Mono", "Roboto Mono", monospace;font-family:var(--font-system);letter-spacing:-.022em;color:var(--text-primary);background:var(--bg-secondary);-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;text-rendering:optimizelegibility;font-size:17px;font-weight:400;line-height:1.47059}*{box-sizing:border-box;margin:0;padding:0}body{min-height:100vh;margin:0}#root{min-height:100vh}h1,h2,h3,h4,h5,h6{letter-spacing:-.022em;color:var(--text-primary);font-weight:600}h1{letter-spacing:-.024em;font-size:32px;line-height:1.125}h2{font-size:24px;line-height:1.16667}h3{font-size:19px;line-height:1.21053}p{color:var(--text-secondary)}a{color:var(--accent);text-decoration:none;transition:opacity .2s}a:hover{text-decoration:underline}::selection{background:#0071e333}.app{flex-direction:column;min-height:100vh;display:flex}.header{-webkit-backdrop-filter:saturate(180%)blur(20px);border-bottom:1px solid var(--border);z-index:100;background:#ffffffb8;justify-content:space-between;align-items:center;height:48px;padding:0 22px;display:flex;position:sticky;top:0}.header h1{color:var(--text-primary);margin:0;font-size:21px;font-weight:600}.user-info{color:var(--text-secondary);align-items:center;gap:16px;font-size:14px;display:flex}.user-info button{color:var(--accent);background:0 0;border-radius:8px;padding:8px 12px;font-size:14px}.user-info button:hover{background:#0071e314}.main{flex:1;width:100%;max-width:980px;margin:0 auto;padding:40px 22px}.loading{height:200px;color:var(--text-secondary);justify-content:center;align-items:center;display:flex}.error{color:var(--error);background:#ff3b3014;border-radius:12px;margin-bottom:20px;padding:12px 16px;font-size:15px}button{font-family:var(--font-system);background:var(--accent);color:#fff;cursor:pointer;border:none;border-radius:980px;justify-content:center;align-items:center;gap:8px;padding:12px 24px;font-size:17px;font-weight:400;transition:all .2s;display:inline-flex}button:hover{background:var(--accent-hover);transform:scale(1.02)}button:active{transform:scale(.98)}button:disabled{background:var(--text-tertiary);cursor:not-allowed;transform:none}.btn-secondary{background:var(--bg-secondary);color:var(--accent)}.btn-secondary:hover{background:#e8e8ed}.btn-danger{background:var(--error)}.btn-danger:hover{background:#ff453a}.btn-ghost{color:var(--accent);background:0 0;padding:8px 16px}.btn-ghost:hover{background:#0071e314;transform:none}.btn-link{background:var(--accent);color:#fff;border-radius:980px;justify-content:center;align-items:center;padding:8px 16px;font-size:13px;text-decoration:none;transition:all .2s;display:inline-flex}.btn-link:hover{background:var(--accent-hover);text-decoration:none}.card-link-wrapper{text-align:center;margin-top:16px}.card-link-btn{background:var(--bg-secondary);color:var(--accent);border-radius:980px;padding:10px 20px;font-size:15px;text-decoration:none;transition:all .2s;display:inline-block}.card-link-btn:hover{background:#e8e8ed;text-decoration:none}.auth-container{background:var(--bg-primary);max-width:400px;box-shadow:var(--shadow-lg);border-radius:20px;margin:80px auto;padding:40px}.auth-container h1{text-align:center;margin-bottom:32px;font-size:28px}.form-group{margin-bottom:20px}.form-group label{color:var(--text-primary);margin-bottom:8px;font-size:14px;font-weight:500;display:block}.form-group input,.form-group textarea{border:1px solid var(--border-strong);width:100%;font-size:17px;font-family:var(--font-system);background:var(--bg-primary);color:var(--text-primary);border-radius:12px;padding:12px 16px;transition:all .2s}.form-group input:focus,.form-group textarea:focus{border-color:var(--accent);outline:none;box-shadow:0 0 0 4px #0071e31f}.form-group input::placeholder,.form-group textarea::placeholder{color:var(--text-tertiary)}.form-group textarea{resize:vertical;min-height:120px;line-height:1.5}.auth-container p{text-align:center;color:var(--text-secondary);margin-top:24px;font-size:15px}.auth-container a{color:var(--accent);font-weight:500}.decks-container{max-width:860px;margin:0 auto}.decks-header{justify-content:space-between;align-items:center;margin-bottom:32px;display:flex}.decks-header h1{margin:0}.header-actions{gap:12px;display:flex}.create-deck-form{background:var(--bg-primary);box-shadow:var(--shadow-md);border-radius:20px;margin-bottom:32px;padding:32px}.decks-list{flex-direction:column;gap:16px;display:flex}.deck-card{background:var(--bg-primary);box-shadow:var(--shadow-sm);border-radius:16px;justify-content:space-between;align-items:center;padding:24px;transition:all .2s;display:flex}.deck-card:hover{box-shadow:var(--shadow-md);transform:translateY(-2px)}.deck-info{flex:1}.deck-info h3{color:var(--text-primary);margin-bottom:6px;font-size:19px;font-weight:600}.deck-info p{color:var(--text-secondary);margin-bottom:12px;font-size:15px}.deck-stats{color:var(--text-tertiary);gap:20px;font-size:13px;display:flex}.deck-stats span{align-items:center;gap:4px;display:flex}.deck-actions{gap:8px;display:flex}.deck-actions button,.deck-actions a{border-radius:980px;padding:10px 18px;font-size:15px;text-decoration:none}.btn-study{background:var(--success);color:#fff}.btn-study:hover{background:#30d158}.btn-edit{background:var(--bg-secondary);color:var(--text-primary)}.btn-edit:hover{background:#e8e8ed}.btn-export{background:var(--bg-secondary);color:var(--text-primary)}.btn-export:hover{background:#e8e8ed}.btn-import{background:var(--bg-secondary);color:var(--text-primary)}.btn-import:hover{background:#e8e8ed}.btn-delete{color:var(--error);background:0 0;padding:10px 14px}.btn-delete:hover{background:#ff3b3014}.study-stats-card{color:#fff;background:linear-gradient(135deg,#1d1d1f 0%,#2c2c2e 100%);border-radius:20px;margin-bottom:32px;padding:28px 32px}.study-stats-card h2{color:#fff9;text-transform:uppercase;letter-spacing:.02em;margin-bottom:20px;font-size:13px;font-weight:500}.stats-grid{grid-template-columns:repeat(4,1fr);gap:24px;display:grid}.stat-item{text-align:center}.stat-value{letter-spacing:-.02em;color:#fff;font-size:34px;font-weight:600;display:block}.stat-label{color:#ffffff80;text-transform:uppercase;letter-spacing:.02em;margin-top:4px;font-size:12px;display:block}@media (width<=768px){.stats-grid{grid-template-columns:repeat(2,1fr)}}.deck-edit-container{max-width:860px;margin:0 auto}.deck-edit-header{align-items:center;gap:20px;margin-bottom:32px;display:flex}.deck-edit-header h1{color:var(--text-primary);margin:0;font-size:28px}.back-btn{background:var(--bg-secondary);color:var(--text-primary);padding:10px 18px;font-size:15px}.back-btn:hover{background:#e8e8ed}.tabs{background:var(--bg-secondary);border-radius:12px;gap:8px;width:fit-content;margin-bottom:24px;padding:4px;display:flex}.tab{color:var(--text-secondary);cursor:pointer;background:0 0;border:none;border-radius:8px;padding:10px 20px;font-size:15px;font-weight:500;transition:all .2s}.tab:hover{color:var(--text-primary);background:0 0;transform:none}.tab.active{background:var(--bg-primary);color:var(--text-primary);box-shadow:var(--shadow-sm)}.tab.active:hover{background:var(--bg-primary)}.deck-form{background:var(--bg-primary);box-shadow:var(--shadow-sm);border-radius:20px;padding:32px}.tags-section{border:1px solid var(--border);background:var(--bg-primary);border-radius:16px;margin-top:32px;padding:24px}.tags-section h3{margin-bottom:8px;font-size:17px;font-weight:600}.tags-section>p{color:var(--text-secondary);margin-bottom:16px;font-size:14px}.add-tag-form{gap:12px;margin-bottom:16px;display:flex}.add-tag-form input{border:1px solid var(--border-strong);font-size:15px;font-family:var(--font-system);background:var(--bg-primary);color:var(--text-primary);border-radius:10px;flex:1;padding:10px 16px}.add-tag-form input:focus{border-color:var(--accent);outline:none;box-shadow:0 0 0 4px #0071e31f}.add-tag-form button{padding:10px 20px;font-size:15px}.tags-list{flex-wrap:wrap;gap:8px;display:flex}.tag-item{background:var(--bg-secondary);border-radius:8px;align-items:center;gap:6px;padding:6px 10px;display:inline-flex}.tag-name{color:var(--text-primary);font-size:14px}.tag-item .btn-icon{width:20px;height:20px;font-size:12px}.no-tags{color:var(--text-tertiary);font-size:14px}.tag-filter-select{border:1px solid var(--border-strong);font-size:15px;font-family:var(--font-system);background:var(--bg-primary);color:var(--text-primary);cursor:pointer;appearance:none;background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath 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#ff3b304d;border-radius:16px;margin-top:32px;padding:24px}.danger-zone h3{color:var(--error);margin-bottom:8px;font-size:15px}.danger-zone p{color:var(--text-secondary);margin-bottom:16px;font-size:14px}.cards-section{background:var(--bg-primary);box-shadow:var(--shadow-sm);border-radius:20px;padding:32px}.cards-header{justify-content:flex-end;margin-bottom:24px;display:flex}.cards-toolbar{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:16px;margin-bottom:24px;display:flex}.cards-toolbar-right{align-items:center;gap:12px;display:flex}.search-box{flex:1;max-width:300px;position:relative}.search-input{border:1px solid var(--border-strong);width:100%;font-size:15px;font-family:var(--font-system);background:var(--bg-primary);color:var(--text-primary);border-radius:10px;padding:10px 36px 10px 16px;transition:all .2s}.search-input:focus{border-color:var(--accent);outline:none;box-shadow:0 0 0 4px #0071e31f}.search-input::placeholder{color:var(--text-tertiary)}.search-clear{background:var(--bg-secondary);width:24px;height:24px;color:var(--text-secondary);border-radius:50%;justify-content:center;align-items:center;padding:0;font-size:12px;display:flex;position:absolute;top:50%;right:8px;transform:translateY(-50%)}.search-clear:hover{background:var(--bg-tertiary);color:var(--text-primary);transform:translateY(-50%)}.sort-select{border:1px solid var(--border-strong);font-size:15px;font-family:var(--font-system);background:var(--bg-primary);color:var(--text-primary);cursor:pointer;appearance:none;background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23666' d='M6 8L1 3h10z'/%3E%3C/svg%3E");background-position:right 12px center;background-repeat:no-repeat;border-radius:10px;padding:10px 32px 10px 16px}.sort-select:focus{border-color:var(--accent);outline:none;box-shadow:0 0 0 4px #0071e31f}@media (width<=768px){.cards-toolbar{flex-direction:column;align-items:stretch}.search-box{max-width:none}.cards-toolbar-right{justify-content:space-between}.sort-select{flex:1}}.card-form-grid{grid-template-columns:1fr 1fr;gap:20px;margin-bottom:20px;display:grid}@media (width<=768px){.card-form-grid{grid-template-columns:1fr}}.form-hint{color:var(--text-tertiary);margin-bottom:16px;font-size:13px}.add-card-form{background:var(--bg-tertiary);border-radius:16px;margin-bottom:24px;padding:24px}.cards-list{flex-direction:column;gap:16px;display:flex}.no-cards{color:var(--text-tertiary);text-align:center;padding:48px 24px;font-size:15px}.card-item{border:1px solid var(--border);border-radius:12px;padding:12px 16px;transition:all .2s;overflow:hidden}.card-item:has(.card-edit){padding:20px}.card-item:hover{border-color:var(--border-strong);background:var(--bg-secondary)}.card-row{justify-content:space-between;align-items:center;gap:16px;display:flex}.card-preview{cursor:pointer;flex:1;align-items:center;gap:12px;min-width:0;display:flex}.card-preview-text{color:var(--text-primary);white-space:nowrap;text-overflow:ellipsis;font-size:15px;overflow:hidden}.card-preview-meta{color:var(--text-tertiary);white-space:nowrap;background:var(--bg-tertiary);border-radius:4px;padding:2px 8px;font-size:12px}.card-row-actions{flex-shrink:0;gap:4px;display:flex}.btn-icon,a.btn-icon{width:32px;height:32px;color:var(--text-secondary);background:0 0;border-radius:8px;justify-content:center;align-items:center;padding:0;font-size:16px;text-decoration:none;display:inline-flex}.btn-icon:hover,a.btn-icon:hover{background:var(--bg-tertiary);color:var(--text-primary);text-decoration:none;transform:none}.btn-icon-danger:hover{color:var(--error);background:#ff3b301a}.card-content{min-width:0;color:var(--text-primary);flex:1;overflow:hidden}.card-side{border-bottom:1px solid var(--border);margin-bottom:16px;padding-bottom:16px}.card-side:last-of-type{border-bottom:none;margin-bottom:0;padding-bottom:0}.card-label{color:var(--text-tertiary);text-transform:uppercase;letter-spacing:.06em;margin-bottom:8px;font-size:11px;font-weight:600;display:block}.card-text{color:var(--text-primary);font-size:15px;line-height:1.5;overflow:hidden}.card-text p{color:var(--text-primary);margin:0 0 8px}.card-text p:last-child{margin-bottom:0}.card-state{color:var(--text-tertiary);margin-top:12px;font-size:12px}.card-actions{flex-direction:column;gap:8px;display:flex}.card-actions button{padding:8px 16px;font-size:13px}.card-edit{width:100%}.card-edit textarea{border:1px solid var(--border-strong);width:100%;font-size:15px;font-family:var(--font-system);background:var(--bg-primary);color:var(--text-primary);resize:vertical;border-radius:12px;min-height:100px;margin-bottom:12px;padding:12px 16px}.card-edit textarea:focus{border-color:var(--accent);outline:none;box-shadow:0 0 0 4px #0071e31f}.card-edit-actions{gap:12px;display:flex}.code-block{color:#d4d4d4;text-align:left;background:#1e1e1e;border-radius:12px;max-width:100%;margin:12px 0;padding:16px 20px;overflow-x:auto}.code-block code{font-family:var(--font-mono);white-space:pre;font-size:13px;line-height:1.6;display:block}.inline-code{background:var(--bg-secondary);color:#d63384;font-family:var(--font-mono);border-radius:6px;padding:2px 8px;font-size:.9em}.study-container{text-align:center;max-width:640px;margin:0 auto}.study-progress{color:var(--text-tertiary);justify-content:center;gap:32px;margin-bottom:24px;font-size:14px;display:flex}.study-complete{background:var(--bg-primary);box-shadow:var(--shadow-md);border-radius:24px;padding:64px 48px}.study-complete h2{color:var(--success);margin-bottom:12px;font-size:28px}.study-complete p{color:var(--text-secondary);margin-bottom:32px;font-size:17px}.flashcard{background:var(--bg-primary);box-shadow:var(--shadow-md);color:var(--text-primary);border-radius:24px;padding:48px 40px}.flashcard-content{text-align:left;flex-direction:column;justify-content:center;min-height:200px;display:flex}.flashcard-front,.flashcard-back{margin-bottom:32px}.flashcard-front h3,.flashcard-back h3{color:var(--text-tertiary);text-transform:uppercase;letter-spacing:.06em;margin-bottom:16px;font-size:12px;font-weight:600}.flashcard-front p,.flashcard-back p{color:var(--text-primary);font-size:21px;line-height:1.4}.flashcard-text{text-align:left}.flashcard-text p{margin:0 0 8px}.flashcard-text p:last-child{margin-bottom:0}.flashcard-back{border-top:1px solid var(--border);padding-top:32px}.show-answer-btn{width:100%;margin-top:24px;padding:16px;font-size:17px}.rating-buttons{margin-top:32px}.rating-buttons p{color:var(--text-secondary);margin-bottom:16px;font-size:15px}.ratings{justify-content:center;gap:12px;display:flex}.rating-btn{border-radius:16px;flex:1;padding:16px 12px;font-size:14px}.rating-1{background:var(--error)}.rating-1:hover{background:#ff453a}.rating-2{background:var(--warning)}.rating-2:hover{background:#ffa00a}.rating-3{background:var(--success)}.rating-3:hover{background:#30d158}.rating-4{background:var(--accent)}.rating-4:hover{background:var(--accent-hover)}.shortcut-hint{opacity:.7;font-size:.8em;font-weight:400}.rating-btn .shortcut-hint{background:#fff3;border-radius:6px;margin-right:6px;padding:2px 8px;font-size:12px;display:inline-block}.progress-bar-container{background:var(--bg-secondary);border-radius:2px;width:100%;height:4px;margin-bottom:16px;overflow:hidden}.progress-bar{background:var(--accent);border-radius:2px;height:100%;transition:width .3s}@media (width<=768px){.header{padding:0 16px}.main{padding:24px 16px}.auth-container{margin:40px 16px;padding:32px 24px}.decks-header{flex-direction:column;align-items:stretch;gap:16px}.deck-card{flex-direction:column;align-items:stretch;gap:20px}.deck-actions{flex-wrap:wrap;justify-content:stretch}.deck-actions a,.deck-actions button{text-align:center;flex:1;min-width:calc(50% - 4px)}.deck-stats{flex-wrap:wrap;gap:12px}.study-container{padding:0}.flashcard{border-radius:20px;padding:32px 24px}.flashcard-content{min-height:160px}.flashcard-front p,.flashcard-back p{font-size:19px}.ratings{flex-wrap:wrap}.rating-btn{flex:45%;min-width:45%}.study-progress{gap:20px;font-size:13px}.card-item{flex-direction:column;gap:16px}.card-actions{flex-direction:row;justify-content:stretch;width:100%}.card-actions button{flex:1}button{padding:14px 24px}.form-group input,.form-group textarea{font-size:16px}.tabs{width:100%}.tab{text-align:center;flex:1}}