:root{--premium-bg-base: #0A0A0B;--premium-bg-elevated: #111113;--premium-bg-surface: #18181B;--premium-bg-card: #1F1F23;--premium-border: rgba(255, 255, 255, .08);--premium-border-strong: rgba(255, 255, 255, .12);--premium-border-hover: rgba(99, 102, 241, .4);--premium-text-primary: #FAFAFA;--premium-text-secondary: #A1A1AA;--premium-text-tertiary: #71717A;--premium-accent: #6366f1;--premium-accent-bright: #818cf8;--premium-accent-glow: rgba(99, 102, 241, .15);--premium-accent-glow-strong: rgba(99, 102, 241, .25);--premium-success: #10B981;--premium-warning: #F59E0B;--premium-danger: #EF4444;--font-mono: "JetBrains Mono", "Menlo", "Monaco", monospace;--font-sans: "Inter", system-ui, -apple-system, sans-serif}.problem-detail-page{background-color:var(--premium-bg-base);color:var(--premium-text-primary);font-family:var(--font-sans);min-height:100vh;display:flex;flex-direction:column}.problem-detail-page.is-simulating{height:100vh;overflow:hidden}:root{--ph-bg-root: #0F0F11;--ph-bg-surface: #18181B;--ph-border: rgba(255, 255, 255, .06);--ph-font-display: "Outfit", sans-serif;--ph-text-primary: #EDEDEF;--ph-text-secondary: #A1A1AA;--ph-text-tertiary: #71717A;--ph-accent-blue: #818cf8;--ph-accent-blue-dim: rgba(99, 102, 241, .1);--badge-easy-bg: rgba(16, 185, 129, .1);--badge-easy-text: #6EE7B7;--badge-pattern-bg: rgba(99, 102, 241, .1);--badge-pattern-text: #a5b4fc}.problem-detail-header{background-color:var(--ph-bg-root);border-bottom:1px solid var(--ph-border);height:72px;width:100%;position:sticky;top:0;z-index:50;display:flex;justify-content:center;-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px)}.header-content-wrapper{width:100%;padding:0 40px;display:flex;align-items:center;height:100%;gap:24px;box-sizing:border-box}.is-simulating .header-content-wrapper{width:100%!important;max-width:none!important;padding:0 32px!important}.systems-header{border-bottom:2px solid rgba(245,158,11,.3)!important;background:linear-gradient(to bottom,rgba(245,158,11,.05),transparent)!important}.systems-header .header-back-btn:hover{color:#f59e0b!important}.system-design-view .idea-panel{max-width:none;width:100%;padding:60px 40px;box-sizing:border-box}.header-back-btn{color:var(--ph-text-secondary);transition:color .2s ease,transform .2s ease;display:flex;align-items:center;justify-content:center}.header-back-btn:hover{color:var(--ph-text-primary);transform:translate(-2px)}.is-simulating .problem-detail-content{width:100vw!important;max-width:100vw!important;padding:0!important;margin:0!important;position:relative!important;left:0!important}.is-simulating .simulation-panel{width:100%!important;height:100%!important}.header-title-section{display:flex;align-items:center;gap:16px;flex:1}.header-title{font-family:var(--ph-font-display);font-size:1.25rem;font-weight:700;color:var(--ph-text-primary);margin:0;line-height:1}.header-badges{display:flex;gap:8px;align-items:center;margin-left:8px;padding-left:16px;border-left:1px solid var(--ph-border);height:24px}.header-badge{font-family:var(--font-mono);font-size:.7rem;font-weight:600;padding:3px 10px;border-radius:99px;display:inline-flex;align-items:center;border:1px solid transparent}.badge-easy{background:var(--badge-easy-bg);color:var(--badge-easy-text);border-color:#10b98126}.badge-medium{background:#f59e0b1a;color:#fcd34d;border-color:#f59e0b26}.badge-hard{background:#ef44441a;color:#fca5a5;border-color:#ef444426}.badge-pattern{background:var(--ph-bg-surface);color:var(--ph-text-secondary);border:1px solid var(--ph-border)}.header-tabs{display:flex;gap:4px;background:#0f172a66;padding:4px;border-radius:12px;border:1px solid rgba(255,255,255,.05);-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px)}.header-tab-btn{display:flex;align-items:center;gap:8px;padding:8px 18px;font-family:var(--font-sans);font-size:.75rem;font-weight:700;letter-spacing:.05em;text-transform:uppercase;border-radius:8px;border:none;cursor:pointer;transition:all .3s cubic-bezier(.4,0,.2,1);color:#64748b;background:transparent}.header-tab-btn:hover{color:var(--ph-text-primary);background:#ffffff08}.header-tab-btn.active{background:#3c3c4199;color:#fff;box-shadow:0 1px 2px #0003;border:1px solid rgba(255,255,255,.08)}.header-tab-btn .tab-icon{width:14px;height:14px;opacity:.8}.header-tab-btn.active .tab-icon{opacity:1;color:var(--ph-accent-blue)}.header-tab-btn.simulation-tab,.tab-button.simulation-tab{color:#34d399;background:#10b9810d;border:1px solid rgba(16,185,129,.1)}.header-tab-btn.simulation-tab.active,.tab-button.simulation-tab.active{background:#10b98126;color:#6ee7b7;border-color:#10b9814d;box-shadow:0 0 15px #10b9811a}.header-tab-btn.simulation-tab .tab-icon,.tab-button.simulation-tab .tab-icon{color:#34d399}.problem-detail-page.pattern-dp{--ph-accent-primary: #10b981;--ph-accent-secondary: #6366f1}.problem-detail-page.pattern-dp .header-tab-btn.active{border-bottom:2px solid var(--ph-accent-primary);background:#10b9810d}.problem-detail-page.pattern-dp .header-tab-btn.simulation-tab.active{background:#10b98126;color:#6ee7b7;border-color:#10b9814d}.problem-detail-page.pattern-dp .header-title{background:linear-gradient(135deg,#fff,#10b981);-webkit-background-clip:text;-webkit-text-fill-color:transparent}.problem-detail-page.pattern-dp .header-badge.badge-pattern{background:#10b9811a;color:#10b981;border:1px solid rgba(16,185,129,.2)}@media(max-width:768px){.problem-detail-header{height:auto;padding:12px 0}.header-content-wrapper{flex-direction:column;padding:0 16px;gap:12px;align-items:flex-start}.header-title-section{width:100%;justify-content:flex-start;gap:12px}.header-title{font-size:1.15rem;line-height:1.3}.header-badges{display:none!important}.header-tabs{width:100%}.header-tab-btn{flex:1;justify-content:center;padding:8px 4px;font-size:12px}}.problem-detail-title-section{display:flex;align-items:center;gap:16px}.problem-detail-title{font-family:var(--font-sans);font-size:1.1rem;font-weight:600;letter-spacing:-.01em;color:var(--op-text-primary);margin:0}.problem-detail-meta{display:flex;align-items:center;gap:12px}.meta-tag{font-family:var(--font-mono);font-size:.75rem;padding:4px 8px;border-radius:4px;font-weight:500;border:1px solid transparent}.meta-tag.difficulty-easy{color:var(--op-accent-success);border-color:#00c85333;background:#00c8530d}.meta-tag.difficulty-medium{color:var(--op-accent-warning);border-color:#ffab0033;background:#ffab000d}.meta-tag.difficulty-hard{color:var(--op-accent-danger);border-color:#d5000033;background:#d500000d}.problem-detail-tabs{display:flex;gap:4px;background:var(--op-bg-surface);padding:4px;border:1px solid var(--op-border-subtle);border-radius:24px;margin-right:auto}.tab-button{padding:6px 16px;font-family:var(--font-sans);font-size:.85rem;color:var(--op-text-secondary);background:transparent;border:none;border-radius:20px;cursor:pointer;transition:all .2s ease}.tab-button:hover{color:var(--op-text-primary);background:#ffffff0d}.tab-button.active{color:var(--op-bg-base);background:var(--op-text-primary);font-weight:600}.problem-detail-content{flex:1;display:flex;overflow:hidden;position:relative}.idea-panel{width:100%;margin:0;padding:48px 40px;box-sizing:border-box}@media(max-width:768px){.idea-panel{padding:24px 16px}}.section-header{display:flex;align-items:center;gap:14px;margin-bottom:28px;font-family:var(--font-mono);color:var(--premium-text-secondary);font-size:.8rem;padding-bottom:12px;border-bottom:1px solid var(--premium-border)}@media(max-width:768px){.section-header{margin-bottom:20px;gap:10px}}.section-header svg{width:16px;height:16px;color:var(--op-accent-primary)}.tech-panel{background:var(--premium-bg-card);border:1px solid var(--premium-border);padding:32px;margin-bottom:32px;position:relative;border-radius:16px;transition:all .3s cubic-bezier(.4,0,.2,1);box-shadow:0 1px 3px #0000004d}@media(max-width:768px){.tech-panel{padding:20px 16px;margin-bottom:20px}}.tech-panel:hover{border-color:var(--premium-border-strong);box-shadow:0 4px 12px #0006}.tech-panel.primary-framing{border-left:2px solid var(--premium-accent);background:linear-gradient(90deg,var(--premium-accent-glow) 0%,var(--premium-bg-card) 100%);box-shadow:0 1px 3px #0000004d,-2px 0 8px var(--premium-accent-glow)}.tech-panel h3{font-family:var(--font-sans);font-size:1.25rem;font-weight:700;color:var(--premium-text-primary);margin-top:0;margin-bottom:22px;letter-spacing:-.02em;line-height:1.3}.hero-text{font-size:1.125rem;line-height:1.8;color:var(--premium-text-primary);font-weight:450;opacity:.95}.io-card{background:var(--premium-bg-elevated);border:1px solid var(--premium-border);border-radius:12px;font-family:var(--font-mono);font-size:.85rem;padding:24px;margin-top:12px;display:grid;gap:18px;transition:all .2s ease;box-shadow:0 1px 2px #0003}.io-card:hover{border-color:var(--premium-border-strong)}.io-label{color:var(--premium-text-tertiary);font-size:.65rem;font-weight:700;display:block}.io-value{color:var(--premium-text-primary);font-weight:500;line-height:1.7}.io-tag{display:inline-block;font-size:.7rem;font-family:var(--font-sans);padding:4px 12px;border-radius:6px;margin-right:0;margin-bottom:10px;font-weight:700}.io-tag.input{background:#ec48991f;color:#f472b6;border:1px solid rgba(236,72,153,.25)}.io-tag.output{background:#10b9811f;color:#34d399;border:1px solid rgba(16,185,129,.25)}.faq-accordion-item{border:1px solid var(--premium-border);border-radius:12px;background:var(--premium-bg-elevated);margin-bottom:12px;transition:all .3s cubic-bezier(.4,0,.2,1);box-shadow:0 1px 2px #0003}.faq-accordion-item:hover{background:var(--premium-bg-surface);border-color:var(--premium-border-hover);box-shadow:0 2px 8px #6366f11a,0 1px 3px #0000004d}.faq-trigger,.approach-trigger{width:100%;padding:18px 22px;display:flex;justify-content:space-between;align-items:center;cursor:pointer;background:transparent!important;border:none;text-align:left;color:var(--premium-text-primary)!important;transition:all .2s ease}.faq-question{font-size:.95rem;font-weight:600;color:var(--premium-text-primary);line-height:1.5;letter-spacing:-.01em}.faq-content{padding:8px 22px 22px 58px;font-size:.925rem;color:var(--premium-text-secondary);line-height:1.8}.approach-spectrum-container{padding:16px 0}.evolution-stepper{display:flex;align-items:center;gap:0;margin-bottom:28px;position:relative;padding:0 12px}.evolution-step{flex:1;position:relative;display:flex;flex-direction:column;align-items:center;gap:10px;min-width:130px}.step-marker{width:14px;height:14px;border-radius:50%;background:var(--premium-border-strong);border:2px solid var(--premium-bg-card);z-index:2;transition:all .4s cubic-bezier(.4,0,.2,1)}.evolution-step.active .step-marker{background:var(--premium-accent);box-shadow:0 0 16px var(--premium-accent-glow-strong),0 0 4px var(--premium-accent);transform:scale(1.3);border-color:var(--premium-accent-bright)}.step-connector{position:absolute;top:6px;left:50%;width:100%;height:2px;background:var(--premium-border);z-index:1;transition:background .3s ease}.evolution-step:last-child .step-connector{display:none}.step-label{font-family:var(--font-mono);font-size:.65rem;color:var(--premium-text-tertiary);text-align:center;transition:color .3s ease;font-weight:600}.evolution-step.active .step-label{color:var(--premium-accent-bright);font-weight:800}.complexity-trail{display:flex;align-items:center;gap:14px;background:var(--premium-bg-elevated);padding:16px 18px;border-radius:12px;border:1px solid var(--premium-border);width:fit-content;box-shadow:0 1px 2px #0003}@media(max-width:768px){.complexity-trail{display:none}}.trail-node{padding:6px 14px;font-family:var(--font-mono);font-size:.825rem;border-radius:8px;border:1px solid var(--premium-border);color:var(--premium-text-secondary);background:var(--premium-bg-surface);transition:all .2s ease}.trail-node.highlight{background:var(--premium-accent-glow);color:var(--premium-accent-bright);border-color:var(--premium-accent);font-weight:700;box-shadow:0 0 12px var(--premium-accent-glow)}.trail-arrow{color:var(--premium-text-tertiary)}.checklist-item{border-radius:12px;background:var(--premium-bg-elevated);border:1px solid var(--premium-border);padding:20px;transition:all .3s ease;box-shadow:0 1px 2px #0003}.checklist-item:hover{border-color:var(--premium-border-strong);box-shadow:0 2px 6px #0000004d}.checklist-icon{display:flex;align-items:center;justify-content:center;width:28px;height:28px;border-radius:6px;background:var(--op-accent-primary-glow);color:var(--op-accent-primary);font-size:.75rem;font-weight:800;flex-shrink:0}.checklist-title{font-weight:600;font-size:.9rem;color:var(--op-text-primary);margin-bottom:4px}.checklist-desc{font-size:.85rem;color:var(--op-text-secondary);line-height:1.6}@keyframes slideIn{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}.cta-scanner{position:relative;overflow:hidden}.cta-scanner:after{content:"";position:absolute;top:-100%;left:0;width:100%;height:100%;background:linear-gradient(to bottom,transparent 0%,var(--premium-accent-glow) 45%,var(--premium-accent-glow-strong) 50%,var(--premium-accent-glow) 55%,transparent 100%);animation:cta-scan 3s cubic-bezier(.4,0,.2,1) infinite;pointer-events:none}@keyframes cta-scan{0%{top:-100%}to{top:100%}}.practice-panel-container{display:flex;flex-direction:row;height:calc(100vh - 64px);width:100%;background-color:#030712;color:#f3f4f6;font-family:system-ui,-apple-system,sans-serif;overflow:hidden}.practice-left-pane{display:flex;flex-direction:column;height:100%;overflow-y:auto;border-right:1px solid #1f2937;background-color:#050b18}.practice-right-pane{display:flex;flex-direction:column;height:100%;overflow:hidden;background-color:#020617}.problem-description-content{padding:24px}.problem-description-header{margin-bottom:20px}.problem-title-text{font-size:24px;font-weight:800;color:#fff;margin:0 0 10px;letter-spacing:-.02em}.problem-meta-row{display:flex;gap:8px;align-items:center}.meta-difficulty-badge{font-size:11px;font-weight:700;text-transform:uppercase;padding:2px 8px;border-radius:4px;letter-spacing:.05em}.meta-difficulty-badge.easy{background-color:#10b9811a;color:#10b981;border:1px solid rgba(16,185,129,.2)}.meta-difficulty-badge.medium{background-color:#f59e0b1a;color:#f59e0b;border:1px solid rgba(245,158,11,.2)}.meta-difficulty-badge.hard{background-color:#ef44441a;color:#ef4444;border:1px solid rgba(239,68,68,.2)}.description-body{font-size:14.5px;line-height:1.6;color:#9ca3af;margin-bottom:28px}.section-subtitle{font-size:15px;font-weight:700;text-transform:uppercase;color:#818cf8;margin:28px 0 14px;letter-spacing:.08em;display:flex;align-items:center;gap:6px}.example-card{background:#11182780;border:1px solid #1f2937;border-radius:8px;padding:16px;margin-bottom:14px}.example-label{font-family:monospace;font-size:13px;color:#e5e7eb;margin-bottom:8px}.example-label span{color:#818cf8;font-weight:700}.example-explanation{font-size:13px;color:#9ca3af;margin-top:8px;border-top:1px dashed #1f2937;padding-top:8px}.constraints-list{margin:0;padding-left:20px}.constraints-list li{font-family:monospace;font-size:13px;color:#f43f5e;margin-bottom:6px}.editor-header-bar{display:flex;justify-content:space-between;align-items:center;padding:10px 16px;background-color:#090d16;border-bottom:1px solid #1f2937;min-width:0;flex-shrink:0;gap:8px}.header-left-controls{display:flex;align-items:center;gap:10px;min-width:0;flex-shrink:1}.header-right-controls{display:flex;align-items:center;gap:10px;flex-shrink:0}.selector-dropdown{background-color:#111827;border:1px solid #374151;color:#f3f4f6;padding:6px 12px;font-size:13px;font-weight:500;border-radius:6px;cursor:pointer;outline:none;transition:border-color .2s}.selector-dropdown:hover{border-color:#818cf8}.practice-btn{display:flex;align-items:center;gap:6px;background-color:#111827;border:1px solid #374151;color:#f3f4f6;padding:6px 12px;font-size:13px;font-weight:600;border-radius:6px;cursor:pointer;transition:all .2s}.practice-btn:hover{border-color:#818cf8;background-color:#1f2937}.practice-btn.run-btn{background-color:#818cf8;border-color:#818cf8;color:#030712}.practice-btn.run-btn:hover{background-color:#a5b4fc;border-color:#a5b4fc;box-shadow:0 0 12px #818cf866}.practice-btn.run-btn:disabled{background-color:#374151;border-color:#374151;color:#9ca3af;cursor:not-allowed;box-shadow:none}.example-pre{font-family:JetBrains Mono,Fira Code,monospace;font-size:13px;background:#0b0f19;padding:12px;border-radius:6px;border:1px solid #1e293b;color:#cbd5e1;overflow-x:auto;white-space:pre-wrap;line-height:1.6}.history-dropdown-wrapper{position:relative}.history-dropdown-menu{display:none;position:absolute;right:0;top:100%;margin-top:4px;background:#111827;border:1px solid #1f2937;border-radius:8px;box-shadow:0 8px 24px #00000080;z-index:50;min-width:180px;padding:6px}.history-dropdown-wrapper:hover .history-dropdown-menu{display:block}.history-dropdown-title{font-size:10px;font-weight:800;color:#6b7280;padding:6px 8px;border-bottom:1px solid #1f2937;letter-spacing:.05em}.history-dropdown-item{display:flex;justify-content:space-between;align-items:center;width:100%;padding:8px;background:none;border:none;border-radius:4px;cursor:pointer;font-family:JetBrains Mono,monospace;font-size:12px;margin-top:2px;color:#e5e7eb}.history-dropdown-item:hover{background:#1f2937}.history-item-lang{color:#818cf8;text-transform:capitalize}.history-item-status.passed{color:#10b981}.history-item-status.failed{color:#f43f5e}.monaco-editor-wrapper{flex:1;position:relative;border-bottom:1px solid #1f2937;min-height:200px}.practice-console-panel{display:flex;flex-direction:column;background-color:#050b18;border-top:1px solid #1f2937}.console-tab-bar{display:flex;background-color:#090d16;border-bottom:1px solid #1f2937;padding:0 16px}.console-tab-btn{background:none;border:none;border-bottom:2px solid transparent;color:#9ca3af;font-size:13px;font-weight:600;padding:10px 16px;cursor:pointer;transition:all .2s}.console-tab-btn:hover{color:#fff}.console-tab-btn.active{color:#818cf8;border-bottom-color:#818cf8}.console-pane-body{flex:1;overflow-y:auto;padding:16px;background-color:#050b18}.test-cases-selector{display:flex;gap:8px;margin-bottom:14px}.tc-select-btn{background-color:#111827;border:1px solid #374151;color:#9ca3af;padding:5px 12px;font-size:12px;font-weight:500;border-radius:4px;cursor:pointer}.tc-select-btn.active{border-color:#818cf8;color:#818cf8;background-color:#818cf80d}.tc-select-btn.passed{border-color:#10b98166;color:#10b981}.tc-select-btn.failed{border-color:#ef444466;color:#ef4444}.tc-detail-box{background-color:#11182799;border:1px solid #1f2937;border-radius:6px;padding:12px;font-family:monospace;font-size:13px}.tc-variable-row{margin-bottom:8px}.tc-variable-row span{color:#9ca3af}.tc-val{color:#e5e7eb;word-break:break-all}.console-log-output{font-family:Courier New,Courier,monospace;font-size:12.5px;line-height:1.5;background-color:#020617;border:1px solid #1f2937;border-radius:6px;padding:14px;color:#10b981;min-height:120px;max-height:250px;overflow-y:auto;white-space:pre-wrap;word-break:break-all}.console-log-output.error{color:#f43f5e;background-color:#f43f5e05}.run-status-banner{display:flex;align-items:center;gap:8px;font-size:14px;font-weight:700;margin-bottom:12px;padding:8px 12px;border-radius:6px;border-left:4px solid transparent}.run-status-banner.success{background-color:#10b98114;color:#10b981;border-left-color:#10b981}.run-status-banner.failed{background-color:#ef444414;color:#ef4444;border-left-color:#ef4444}.run-status-banner.custom,.run-status-banner.running{background-color:#818cf814;color:#818cf8;border-left-color:#818cf8}.terminal-loader{display:flex;align-items:center;gap:12px;color:#818cf8;font-family:monospace;font-size:13px;padding:20px;justify-content:center}.loader-spinner{width:20px;height:20px;border:2px solid rgba(129,140,248,.1);border-top:2px solid #818CF8;border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}.custom-input-area{display:flex;flex-direction:column;gap:8px}.custom-input-label{font-size:13px;font-weight:600;color:#9ca3af}.custom-input-textbox{background-color:#020617;border:1px solid #374151;border-radius:6px;color:#f3f4f6;font-family:monospace;font-size:13px;padding:10px;min-height:80px;outline:none;resize:vertical}.custom-input-textbox:focus{border-color:#818cf8}.drag-handle{width:4px;cursor:col-resize;background-color:#1f2937;transition:background-color .2s;height:100%}.drag-handle:hover,.drag-handle.dragging{background-color:#818cf8;width:4px}.practice-left-pane::-webkit-scrollbar,.console-log-output::-webkit-scrollbar,.console-pane-body::-webkit-scrollbar{width:6px;height:6px}.practice-left-pane::-webkit-scrollbar-track,.console-log-output::-webkit-scrollbar-track,.console-pane-body::-webkit-scrollbar-track{background:#050b18}.practice-left-pane::-webkit-scrollbar-thumb,.console-log-output::-webkit-scrollbar-thumb,.console-pane-body::-webkit-scrollbar-thumb{background:#1f2937;border-radius:3px}.practice-left-pane::-webkit-scrollbar-thumb:hover,.console-log-output::-webkit-scrollbar-thumb:hover,.console-pane-body::-webkit-scrollbar-thumb:hover{background:#4b5563}