:root{--bg-color:#f8fafc;--card-bg:#ffffffd9;--card-border:#00000014;--primary:#4f46e5;--primary-glow:#4f46e533;--text-main:#1e293b;--text-muted:#64748b;--accent:#e11d48;--font-sans:"Inter", "Noto Sans JP", sans-serif}*{box-sizing:border-box;margin:0;padding:0}body{background-color:var(--bg-color);color:var(--text-main);font-family:var(--font-sans);line-height:1.6;overflow-x:hidden}#root{flex-direction:column;min-height:100vh;display:flex}.glass{background:var(--card-bg);-webkit-backdrop-filter:blur(8px);border:1px solid var(--card-border);border-radius:12px;box-shadow:0 4px 6px -1px #0000001a,0 2px 4px -1px #0000000f}header{z-index:100;-webkit-backdrop-filter:blur(12px);border-bottom:1px solid var(--card-border);background:#f8fafccc;justify-content:space-between;align-items:center;padding:.75rem 2rem;display:flex;position:sticky;top:0}.subtitle{color:var(--text-muted);font-size:.9rem;font-weight:500}.main-nav{gap:2rem;display:flex}.header-brand{text-align:right}.main-nav button{color:var(--text-muted);cursor:pointer;letter-spacing:.05em;background:0 0;border:none;padding:.5rem 0;font-size:.85rem;font-weight:800;transition:color .3s;position:relative}.main-nav button:hover,.main-nav button.active{color:var(--text-main)}.main-nav button.active:after{content:"";background:var(--primary);width:100%;height:3px;box-shadow:0 2px 4px var(--primary-glow);border-radius:2px;position:absolute;bottom:-2px;left:0}h1{letter-spacing:-.04em;background:linear-gradient(135deg,#4f46e5 0%,#9333ea 50%,#db2777 100%);-webkit-text-fill-color:transparent;filter:drop-shadow(0 4px 8px #4f46e526);-webkit-background-clip:text;background-clip:text;margin-bottom:0;font-size:1.8rem;font-weight:900}.search-container{max-width:800px;margin:.5rem auto 1.5rem;padding:0 1rem}.search-input{border:1px solid var(--card-border);width:100%;color:var(--text-main);background:#fff;border-radius:12px;outline:none;padding:.75rem 1.25rem;font-size:1rem;transition:all .3s;box-shadow:0 2px 4px #0000000d}.search-input:focus{border-color:var(--primary);box-shadow:0 0 0 3px var(--primary-glow)}.filters{border:1px solid var(--card-border);background:#fff;border-radius:12px;flex-direction:column;gap:1rem;margin-bottom:1.5rem;padding:1.25rem;display:flex;box-shadow:0 2px 4px #0000000d}.filter-group{flex:1;align-items:center;gap:.75rem;display:flex}.filter-row{gap:1.5rem;width:100%;display:flex}@media (width<=768px){.filter-row{flex-direction:column;gap:1rem}}.filter-group label{color:var(--text-muted);text-transform:uppercase;letter-spacing:.05em;min-width:50px;font-size:.8rem;font-weight:700}.chip-group{flex-wrap:wrap;gap:.4rem;display:flex}.filter-chip{cursor:pointer;color:var(--text-main);background:#f1f5f9;border:1px solid #0000;border-radius:6px;outline:none;padding:.4rem .8rem;font-size:.8rem;transition:all .2s}.filter-chip:hover{background:#e2e8f0}.filter-chip.active{background:var(--primary);color:#fff;box-shadow:0 2px 8px var(--primary-glow)}main{flex:1;width:100%;max-width:1400px;margin:0 auto;padding:1rem 1.5rem}.problem-grid{grid-template-columns:repeat(2,1fr);gap:1.5rem;padding:.5rem 0;display:grid}@media (width<=900px){.problem-grid{grid-template-columns:1fr}}.problem-card{flex-direction:column;padding:1.5rem;transition:all .3s cubic-bezier(.4,0,.2,1);display:flex;position:relative;overflow:hidden}.problem-card:hover{border-color:var(--primary);transform:translateY(-6px)scale(1.01);box-shadow:0 25px 50px -12px #00000026}.problem-header{color:var(--text-muted);justify-content:space-between;align-items:center;margin-bottom:1rem;font-size:.85rem;display:flex}.problem-id{background:#0000000d;border-radius:4px;padding:2px 8px;font-family:monospace}.problem-meta{flex-wrap:wrap;gap:.5rem;margin-bottom:1rem;display:flex}.tag{color:var(--primary);background:#4f46e514;border-radius:12px;padding:2px 10px;font-size:.75rem}.level-tag{font-weight:700}.level-A{color:#10b981}.level-B{color:#3b82f6}.level-C{color:#f59e0b}.level-D{color:#ef4444}.problem-content{flex:1;min-height:100px;margin-bottom:1.5rem;font-size:1.05rem;overflow-x:auto}.problem-preview{border:1px solid var(--card-border);background:#fff;border-radius:8px;justify-content:center;align-items:center;margin-bottom:1.25rem;padding:1rem;transition:transform .3s;display:flex}.problem-preview img{max-width:100%;height:auto;display:block}.problem-card-footer{border-top:1px solid var(--card-border);grid-template-columns:1fr 1fr;gap:.75rem;margin-top:auto;padding-top:1rem;display:grid}.card-btn{cursor:pointer;border:none;border-radius:8px;justify-content:center;align-items:center;gap:6px;padding:.6rem .5rem;font-size:.8rem;font-weight:700;transition:all .2s;display:flex}.btn-icon{font-size:.9rem}.solution-btn.active{color:#fff;background:linear-gradient(135deg,#6366f1 0%,#4f46e5 100%);box-shadow:0 4px 12px #4f46e54d}.solution-btn.active:hover{transform:translateY(-2px);box-shadow:0 6px 15px #4f46e566}.solution-btn.disabled{color:#94a3b8;cursor:not-allowed;opacity:.7;background:#e2e8f0}.copy-btn{border:1px solid var(--card-border);color:var(--text-main);background:#fff}.copy-btn:hover{border-color:var(--primary);color:var(--primary);background:#f8fafc}.modal-overlay{-webkit-backdrop-filter:blur(12px);z-index:1000;background:#0f172ab3;justify-content:center;align-items:center;padding:2rem;display:flex;position:fixed;inset:0}.modal-container{background:#fff;flex-direction:column;width:100%;max-width:900px;max-height:90vh;display:flex;position:relative;overflow:hidden}.modal-header{border-bottom:1px solid var(--card-border);justify-content:space-between;align-items:center;padding:1.25rem 1.5rem;display:flex}.modal-title-group{flex-direction:column;display:flex}.modal-problem-id{color:var(--primary);font-size:1.1rem;font-weight:900}.modal-source{color:var(--text-muted);font-size:.8rem}.close-button{cursor:pointer;width:36px;height:36px;color:var(--text-muted);background:#f1f5f9;border:none;border-radius:50%;justify-content:center;align-items:center;font-size:1.5rem;transition:all .2s;display:flex}.close-button:hover{color:#fff;background:#ef4444;transform:rotate(90deg)}.modal-content{background:#f8fafc;flex:1;justify-content:center;padding:1.5rem;display:flex;overflow-y:auto}.solution-image-container{background:#fff;border-radius:8px;padding:1rem;box-shadow:0 10px 30px #0000001a}.solution-image-container img{max-width:100%;height:auto;display:block}.modal-footer{border-top:1px solid var(--card-border);justify-content:space-between;align-items:center;padding:1rem 1.5rem;display:flex}.modal-hint{color:var(--text-muted);font-size:.8rem;font-style:italic}.modal-download-btn{background:var(--primary);color:#fff;cursor:pointer;border:none;border-radius:6px;padding:.5rem 1rem;font-size:.85rem;font-weight:700}.animate-fade-in{animation:.3s forwards fadeInModal}.animate-scale-up{animation:.3s cubic-bezier(.34,1.56,.64,1) forwards scaleUp}@keyframes fadeInModal{0%{opacity:0}to{opacity:1}}@keyframes scaleUp{0%{opacity:0;transform:scale(.9)translateY(20px)}to{opacity:1;transform:scale(1)translateY(0)}}@media (width<=640px){.modal-overlay{padding:.5rem}.modal-container{border-radius:0;max-height:100vh}.problem-card-footer{grid-template-columns:1fr}}.copy-badge{-webkit-backdrop-filter:blur(4px);backdrop-filter:blur(4px);color:#fff;z-index:20;pointer-events:none;background:#4f46e5b3;border-radius:12px;justify-content:center;align-items:center;font-size:1.5rem;font-weight:900;animation:.3s cubic-bezier(.175,.885,.32,1.275) forwards badgeIn;display:flex;position:absolute;inset:0}@keyframes badgeIn{0%{opacity:0;transform:scale(1.1)}to{opacity:1;transform:scale(1)}}