.hero{text-align:center;padding:2.5rem 1.5rem;background-color:var(--surface-card,#fff);border-radius:12px;border:1px solid var(--line-1,#e5e7eb);margin-bottom:2rem;box-shadow:var(--shadow-md,0 6px 16px rgba(0,0,0,.08));}.hero h1{text-align:center;}.hero p{font-size:1.1rem;color:var(--text-muted,#6b7280);max-width:650px;margin:0 auto;}.content-section{margin-top:3rem;}.content-card{background:var(--surface-card,#fff);border:1px solid var(--line-1,#e5e7eb);border-radius:12px;padding:2rem;margin-bottom:2rem;box-shadow:var(--shadow-sm,0 2px 8px rgba(0,0,0,.06));}.content-card h2{color:var(--blue-600,#2563eb);margin-top:0;border-bottom:2px solid var(--blue-100,#dbeafe);padding-bottom:0.5rem;margin-bottom:1rem;}.content-card p{line-height:1.7;color:var(--text-muted,#6b7280);}.rule-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:1.5rem;margin-top:2rem;}.rule-item{display:flex;flex-direction:column;background-color:var(--surface-card,#fff);padding:1.5rem;border-radius:8px;border:1px solid var(--line-1,#e5e7eb);text-align:left;text-decoration:none;color:inherit;transition:transform .2s ease,box-shadow .2s ease;}.rule-item:hover{transform:translateY(-5px);box-shadow:var(--shadow-md,0 6px 16px rgba(0,0,0,.08));}.rule-item h4{margin-top:0;margin-bottom:.75rem;color:var(--blue-600,#2563eb);}.rule-item p{font-size:.95rem;color:var(--text-muted,#6b7280);margin:0;line-height:1.6;flex-grow:1;}.rule-item .rule-formula{margin-top:1rem;padding-top:1rem;border-top:1px solid var(--line-1,#e5e7eb);text-align:center;}.calculator-card{position:relative;background:var(--surface-card,#fff);border-radius:14px;border:1px solid var(--line-1,#e5e7eb);padding:2rem;box-shadow:var(--shadow-md,0 6px 16px rgba(0,0,0,.08));margin-bottom:2rem;overflow:hidden;}.calculator-card::after{content:"";position:absolute;inset:0 0 auto 0;height:6px;background:linear-gradient(90deg,var(--blue-600,#2563eb),#3ea0e6,#9ad0ff);}.calculator-card label{display:block;font-weight:700;margin-bottom:.5rem;color:var(--blue-600,#2563eb);}.calculator-card form.calc-grid{display:grid !important;grid-template-columns:minmax(0,1fr) 180px;column-gap:1rem;row-gap:.75rem;align-items:start;}.calc-grid .input-area{grid-column:1;grid-row:1;}.calc-grid .formula-side{grid-column:2;grid-row:1;}.calc-grid .formula-left{grid-column:1;grid-row:2;}.calc-grid .actions{grid-column:2;grid-row:2;align-self:end;}.input-with-clear{position:relative;}.input-with-clear .clear-button{position:absolute;right:.5rem;top:50%;transform:translateY(-50%);width:28px;height:28px;border-radius:50%;border:none;background-color:#e9ecef;cursor:pointer;display:none;align-items:center;justify-content:center;font-size:1.2rem;line-height:1;padding:0;z-index:5;}.input-with-clear.has-value .clear-button{display:inline-flex;}.input-with-clear .clear-button:hover{background-color:#dee2e6;}.input-with-clear .clear-button:focus-visible{outline:2px solid var(--blue-500,#3b82f6);outline-offset:2px;}#expr-input{width:100%;padding:.8rem 2.75rem .8rem .8rem;font-size:1.1rem;border:1px solid var(--line-1,#e5e7eb);border-radius:10px;box-sizing:border-box;background:#fff;}#expr-input:focus{border-color:var(--blue-500,#3b82f6);box-shadow:0 0 0 3px rgba(59,130,246,.15);outline:none;}.live-preview{width:100%;min-height:140px;border:1px solid var(--line-1,#e5e7eb);border-radius:10px;display:flex;align-items:center;justify-content:center;font-size:1.2rem;box-sizing:border-box;background:var(--surface-card,#fff);}.diff-select{width:100%;padding:.75rem;font-size:1.05rem;border:1px solid var(--line-1,#e5e7eb);border-radius:10px;height:47px;box-sizing:border-box;background:#fff;}.diff-select:focus{border-color:var(--blue-500,#3b82f6);box-shadow:0 0 0 3px rgba(59,130,246,.15);outline:none;}.submit-button{width:100%;padding:.9rem 1rem;font-size:.95rem;font-weight:700;color:#fff;background-color:var(--blue-600,#2563eb);border:1px solid var(--blue-600,#2563eb);border-radius:10px;cursor:pointer;display:inline-flex;align-items:center;justify-content:center;line-height:1;transition:transform .15s ease,filter .15s ease,background-color .2s ease;}.submit-button:hover{transform:translateY(-1px);filter:brightness(1.02);}.submit-button:active{transform:translateY(0);filter:brightness(.98);}.submit-button:focus-visible{outline:2px solid #fff;box-shadow:0 0 0 3px rgba(37,99,235,.5);outline-offset:2px;}.solution-title{margin-top:3rem;margin-bottom:1.5rem;font-size:1.75rem;color:var(--blue-600,#2563eb);border-bottom:2px solid var(--line-1,#e5e7eb);padding-bottom:.5rem;}.calc-card{background:#fff;border:1px solid var(--blue-200,#d6e4ff);border-radius:8px;margin-bottom:1.5rem;box-shadow:var(--shadow-sm,0 2px 8px rgba(0,0,0,.06));}.calc-card-header{padding:.75rem 1.25rem;background-color:var(--blue-100,#eaf2ff);color:var(--blue-600,#2563eb);border-bottom:1px solid var(--blue-200,#d6e4ff);font-weight:700;}.calc-card-body{padding:1.25rem;}.calc-rule-box{background:var(--surface-bg,#f8f9fa);border-left:4px solid var(--blue-600,#2563eb);padding:1rem;border-radius:4px;margin-bottom:1.25rem;}.calc-rule-box ul{list-style-type:disc;list-style-position:inside;margin:.5rem 0;padding-left:.5rem;}.calc-rule-box ol{list-style-type:decimal;list-style-position:inside;margin:.5rem 0;padding-left:.5rem;}.calc-rule-box li{margin:.25rem 0;}.calc-step-grid{display:grid;gap:1.25rem;}.calc-formula-col{border:1px solid var(--line-1,#dee2e6);border-radius:6px;overflow:hidden;background:var(--surface-card,#fff);}.calc-formula-col>h6{display:flex;align-items:center;gap:.6rem;padding:.6rem 1rem;background-color:var(--surface-bg,#f8f9fa);border-bottom:1px solid var(--line-1,#dee2e6);font-size:.9rem;font-weight:500;color:#495057;margin:0;}.calc-formula-col>.calc-math-box{margin:1rem;}.calc-math-box{overflow-x:auto;padding:10px;background:var(--surface-card,#fff);border:1px solid var(--line-1,#dee2e6);border-radius:4px;}.calc-card.calc-border-green{border-color:#198754 !important;}.calc-card-header.calc-header-green{background-color:#19875a;color:#fff;border-bottom-color:#19875a;}.calc-badge{display:inline-block;padding:.35em .65em;font-size:.75em;font-weight:700;line-height:1;color:#fff;text-align:center;white-space:nowrap;vertical-align:baseline;border-radius:.375rem;margin-left:.25rem;}.calc-badge-green{background-color:#198754;}.calc-badge-red{background-color:#dc3545;}.calc-btn-group{display:flex;flex-wrap:wrap;align-items:center;gap:.75rem;margin:0;padding:0;}.calc-btn-group form{margin:0;padding:0;display:inline;}.calc-btn-group a,.calc-btn-group button{font-family:inherit;font-size:.9rem;font-weight:500;padding:.5rem 1rem;border:1px solid var(--line-1,#e5e7eb);border-radius:8px;text-decoration:none;cursor:pointer;line-height:1.4;transition:background-color .2s ease,border-color .2s ease,transform .2s ease;}.calc-btn-group a{color:var(--ink-900,#111827);background-color:#fff;}.calc-btn-group a:hover{background-color:var(--surface-bg,#f8f9fa);border-color:#ced4da;}.calc-btn-group a:focus-visible{outline:2px solid var(--blue-500,#3b82f6);outline-offset:2px;}.calc-btn-group button{color:#fff;background-color:var(--blue-600,#2563eb);border-color:var(--blue-600,#2563eb);}.calc-btn-group button:hover{background-color:var(--blue-500,#3b82f6);border-color:var(--blue-500,#3b82f6);transform:translateY(-2px);}.calc-btn-group button:active{transform:translateY(0);}.calc-btn-group button:focus-visible{outline:2px solid #fff;box-shadow:0 0 0 3px rgba(59,130,246,.5);outline-offset:2px;}.calc-border-red{border-color:#dc3545 !important;}.calc-card-header.calc-header-red{background-color:#dc3545;color:#fff;border-bottom-color:#dc3545;}.calc-card.calc-border-red .calc-card-body{background:#fff;}.calc-card.calc-border-red .calc-alert,.calc-card.calc-border-red .calc-alert-red{background:transparent;border:0;padding:0;margin:0 0 .25rem 0;}.calc-error-line{font-size:.95rem;margin-bottom:.75rem;}.calc-error-line strong{margin-right:.35rem;font-weight:700;}.calc-problem-label{margin-top:.5rem;margin-bottom:.25rem;font-weight:700;font-size:.95rem;}.calc-code-bad{display:inline-block;padding:0;border:0;background:transparent;color:#dc3545;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,"Liberation Mono","Courier New",monospace;font-size:.95rem;white-space:pre-wrap;font-weight:600;}.placeholder-square{color:#d32f2f;}@media (max-width:768px){.calculator-card form.calc-grid{grid-template-columns:minmax(0,1fr);row-gap:1.5rem;}.calc-grid .input-area,.calc-grid .formula-side,.calc-grid .formula-left,.calc-grid .actions{grid-column:auto;grid-row:auto;align-self:auto;}.live-preview{min-height:100px;}}