:root{
  --bg:#f7fbff;
  --card:#ffffff;
  --text:#0b2540;
  --accent:#0b66ff;
  --accent-2:#0b3dbb;
  --muted:#6b7280;
  --muted-2:#94a3b8;
  --container-width:1100px;
  --radius:10px;
  font-family: "Inter", ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial;
}
*{box-sizing:border-box}
.container{max-width:var(--container-width);margin:0 auto;padding:28px}
.site-header{background:linear-gradient(90deg, rgba(11,102,255,0.06), rgba(11,61,187,0.03));backdrop-filter:blur(6px);border-bottom:1px solid rgba(15,23,42,0.06)}
.site-header .container{display:flex;align-items:center;justify-content:space-between;gap:16px}
.logo{font-weight:700;color:var(--accent-2);text-decoration:none;font-size:20px;letter-spacing:0.2px}
.main-nav a{margin-left:18px;color:var(--text);text-decoration:none;padding:8px 10px;border-radius:8px;font-weight:500}
.main-nav a:hover{background:rgba(11,102,255,0.08);color:var(--accent-2)}
.main-nav a.active{background:linear-gradient(90deg,var(--accent),var(--accent-2));color:#fff}
.main-nav a:focus{outline:3px solid rgba(11,102,255,0.12);outline-offset:2px}
.hero{display:flex;gap:28px;align-items:center;padding:48px 0;background:linear-gradient(180deg,#ffffff 0%, #f1f8ff 100%);border-radius:var(--radius);box-shadow:0 8px 30px rgba(11,38,77,0.06);padding-left:32px;padding-right:32px}
.hero-left{flex:1;max-width:56%}
.hero-right{flex:1;display:flex;justify-content:center;align-items:center}
.hero-right img{max-width:420px;width:100%;height:auto;border-radius:12px;box-shadow:0 10px 30px rgba(11,38,77,0.08);border:1px solid rgba(11,38,77,0.04)}
.lede{font-size:18px;color:var(--muted);margin-top:10px}
.tagline{display:inline-block;background:linear-gradient(90deg,var(--accent),var(--accent-2));color:#fff;padding:6px 10px;border-radius:999px;font-size:13px;margin-bottom:12px}
.quick-stats{margin:14px 0;background:linear-gradient(90deg, rgba(11,102,255,0.04), rgba(11,61,187,0.02));padding:14px;border-radius:10px;color:var(--text);border:1px solid rgba(11,38,77,0.03)}
.cta{background:linear-gradient(90deg,var(--accent),var(--accent-2));color:#fff;padding:12px 16px;border-radius:10px;text-decoration:none;margin-right:12px;box-shadow:0 8px 20px rgba(11,102,255,0.12);display:inline-block;cursor:pointer;border:none;font-size:14px;font-weight:600;transition:all 0.2s ease}
.cta:hover{transform:translateY(-2px);box-shadow:0 12px 28px rgba(11,102,255,0.18)}
.cta:active{transform:translateY(0)}
.cta.secondary{background:#fff;color:var(--accent-2);border:1px solid rgba(11,61,187,0.08)}
.cta.secondary:hover{background:rgba(11,102,255,0.04)}
.muted{color:var(--accent-2);text-decoration:none}
.overview h2{margin-top:10px;color:var(--accent-2)}
.cards{display:flex;gap:18px;margin-top:18px;flex-wrap:wrap}
.card{flex:1;min-width:220px;padding:18px;border-radius:12px;background:var(--card);box-shadow:0 8px 20px rgba(15,23,42,0.04);border-left:4px solid rgba(11,102,255,0.12);text-decoration:none;color:inherit;transition:transform 0.2s ease, box-shadow 0.2s ease}
.card:hover{transform:translateY(-4px);box-shadow:0 12px 28px rgba(15,23,42,0.08)}
.card h3{margin-top:0;color:var(--accent-2)}
.pascal img{max-width:600px;width:100%;height:auto;border-radius:8px;border:1px solid rgba(11,38,77,0.04);box-shadow:0 8px 20px rgba(11,38,77,0.04)}
.site-footer{border-top:1px solid rgba(15,23,42,0.04);padding:28px 0;margin-top:36px;color:var(--muted);background:transparent}
.image-link{display:inline-block}
@media(max-width:980px){
  .hero{flex-direction:column;padding:28px}
  .hero-left{max-width:100%}
  .hero-right img{max-width:80%}
  .cards{flex-direction:column}
}

/* Additional layout helpers for homepage */
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-top:12px}
.panel{background:var(--card);padding:16px;border-radius:12px;box-shadow:0 6px 18px rgba(15,23,42,0.03);border:1px solid rgba(11,38,77,0.03)}
.mono{font-family:ui-monospace, SFMono-Regular, Menlo, Monaco, "Roboto Mono", monospace;background:linear-gradient(90deg, rgba(11,102,255,0.02), rgba(11,61,187,0.01));padding:6px;border-radius:6px;display:inline-block}
.accent{color:var(--accent-2);font-weight:700}
.panel h4{margin:4px 0 8px 0}

@media(max-width:980px){
  .grid{grid-template-columns:1fr}
}

/* ============================================
   Interactive Page Styles
   ============================================ */

/* Page Header */
.page-header{text-align:center;padding:32px 0 40px}
.page-header h1{font-size:36px;color:var(--text);margin:12px 0 16px;font-weight:700}
.page-header .lede{max-width:680px;margin:0 auto;font-size:17px;line-height:1.6}

/* Calculator Section */
.calculator-section{display:grid;grid-template-columns:1fr 1fr;gap:24px;margin-bottom:40px}
@media(max-width:900px){
  .calculator-section{grid-template-columns:1fr}
}

/* Calculator Card */
.calculator-card{background:var(--card);border-radius:16px;padding:28px;box-shadow:0 8px 30px rgba(11,38,77,0.08);border:1px solid rgba(11,38,77,0.04)}
.formula-display{text-align:center;padding:20px;background:linear-gradient(135deg, rgba(11,102,255,0.03), rgba(11,61,187,0.06));border-radius:12px;margin-bottom:24px}
.formula-label{display:block;font-size:12px;text-transform:uppercase;letter-spacing:1px;color:var(--muted);margin-bottom:8px}
.formula-equation{font-family:"Georgia", serif;font-size:32px;color:var(--text);font-weight:600}

/* Input Container - Equal width 3 columns */
.input-container{display:grid;grid-template-columns:1fr 1fr 1fr;gap:20px;margin-bottom:24px;align-items:start}
@media(max-width:700px){.input-container{grid-template-columns:1fr}}
.input-field{display:flex;flex-direction:column}
.input-field label{font-size:13px;font-weight:600;color:var(--text);margin-bottom:8px}
.input-field input{padding:14px 16px;border:1px solid rgba(11,38,77,0.12);border-radius:10px;font-size:16px;transition:all 0.2s ease;background:#fafbfc;width:100%}
.input-field input:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px rgba(11,102,255,0.1);background:#fff}
.input-hint{font-size:11px;color:var(--muted);margin-top:6px}

/* Button Row */
.button-row{display:flex;gap:12px;flex-wrap:wrap;justify-content:flex-start}

/* Button Styles */
.btn{display:inline-flex;align-items:center;gap:8px;padding:10px 16px;font-family:ui-sans-serif, system-ui, sans-serif;font-size:14px;font-weight:500;line-height:1;border:1px solid rgba(11,38,77,0.12);border-radius:8px;cursor:pointer;transition:all 0.2s ease;background:#fff}
.btn svg{flex-shrink:0}

/* Primary Button */
.btn-primary{background:linear-gradient(135deg, #0b66ff, #0b3dbb);color:#fff;border-color:transparent}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 6px 20px rgba(11,102,255,0.25)}
.btn-primary:active{transform:translateY(0)}

/* Secondary Button */
.btn-secondary{color:#0b2540}
.btn-secondary:hover{background:rgba(11,102,255,0.04);border-color:rgba(11,102,255,0.3)}
.btn-secondary:active{background:rgba(11,102,255,0.08)}

/* Result Card */
.result-card{background:var(--card);border-radius:16px;padding:28px;box-shadow:0 8px 30px rgba(11,38,77,0.08);border:1px solid rgba(11,38,77,0.04)}
.result-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px}
.result-header h2{margin:0;font-size:20px;color:var(--text)}
.result-badge{background:linear-gradient(90deg, var(--accent), var(--accent-2));color:#fff;padding:6px 14px;border-radius:20px;font-size:13px;font-weight:600}

/* Expansion Display */
.expansion-container{background:linear-gradient(135deg, #f8fafc, #f1f5f9);border-radius:12px;padding:24px;margin-bottom:20px;max-height:200px;overflow-y:auto}
.expansion-display{font-family:"Georgia", serif;font-size:20px;line-height:1.8;color:var(--text);margin:0;white-space:pre-wrap;word-break:break-word}

/* Result Details */
.result-details{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-bottom:16px}
@media(max-width:600px){
  .result-details{grid-template-columns:1fr}
}
.detail-item{background:#f8fafc;border-radius:10px;padding:14px;text-align:center}
.detail-label{display:block;font-size:12px;color:var(--muted);margin-bottom:4px}
.detail-value{font-size:24px;font-weight:700;color:var(--accent-2)}

/* Copy Success Toast */
.copy-success{position:fixed;bottom:30px;left:50%;transform:translateX(-50%) translateY(100px);background:var(--text);color:#fff;padding:14px 24px;border-radius:10px;display:flex;align-items:center;gap:10px;box-shadow:0 8px 30px rgba(0,0,0,0.2);opacity:0;transition:all 0.3s ease;z-index:1000}
.copy-success.show{transform:translateX(-50%) translateY(0);opacity:1}

/* Visualization Section */
.visualization-section{background:var(--card);border-radius:16px;padding:28px;margin-bottom:40px;box-shadow:0 8px 30px rgba(11,38,77,0.08)}
.visualization-section h3{margin:0 0 20px;font-size:20px;color:var(--text)}
.coefficients-bar{display:flex;justify-content:space-around;align-items:flex-end;height:180px;padding:20px 10px 0;background:linear-gradient(180deg, rgba(11,102,255,0.02), transparent);border-radius:10px}
.bar-item{display:flex;flex-direction:column;align-items:center;flex:1;max-width:80px}
.bar{width:100%;background:linear-gradient(180deg, var(--accent), var(--accent-2));border-radius:8px 8px 0 0;min-height:8px;position:relative;transition:all 0.3s ease}
.bar:hover{background:linear-gradient(180deg, var(--accent-2), #0841a0)}
.bar-value{position:absolute;top:-28px;left:50%;transform:translateX(-50%);font-size:14px;font-weight:600;color:var(--accent-2)}
.bar-label{margin-top:10px;font-size:12px;color:var(--muted)}

/* Guide Section */
.guide-section{margin-bottom:48px}
.guide-section h2{font-size:28px;color:var(--text);text-align:center;margin-bottom:32px}
.steps-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;margin-bottom:32px}
@media(max-width:1000px){.steps-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:600px){.steps-grid{grid-template-columns:1fr}}
.step-card{background:var(--card);border-radius:14px;padding:24px;position:relative;box-shadow:0 6px 20px rgba(11,38,77,0.06);transition:transform 0.2s ease}
.step-card:hover{transform:translateY(-4px)}
.step-number{position:absolute;top:-16px;left:24px;width:36px;height:36px;background:linear-gradient(135deg, var(--accent), var(--accent-2));color:#fff;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:16px}
.step-content h4{margin:8px 0 12px;color:var(--text);font-size:17px}
.step-content p{font-size:14px;color:var(--muted);line-height:1.6;margin:0}
.example-badge{display:inline-block;margin-top:12px;background:linear-gradient(90deg, rgba(11,102,255,0.06), rgba(11,61,187,0.04));padding:8px 12px;border-radius:8px;font-size:13px;color:var(--accent-2);font-weight:500}

/* Tips Box */
.tips-box{background:linear-gradient(135deg, #fff9e6, #fff3cd);border-radius:14px;padding:24px 28px;border:1px solid rgba(255,193,7,0.2)}
.tips-box h4{margin:0 0 16px;color:#856404;font-size:18px}
.tips-box ul{margin:0;padding-left:20px}
.tips-box li{margin-bottom:10px;color:#856404;line-height:1.5}
.tips-box li:last-child{margin-bottom:0}

/* FAQ Section */
.faq-section{margin-bottom:48px}
.faq-section h2{font-size:28px;color:var(--text);text-align:center;margin-bottom:32px}
.faq-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:16px}
@media(max-width:800px){.faq-grid{grid-template-columns:1fr}}
.faq-item{background:var(--card);border-radius:12px;overflow:hidden;box-shadow:0 4px 16px rgba(11,38,77,0.04)}
.faq-item summary{padding:18px 20px;cursor:pointer;font-weight:600;color:var(--text);position:relative;list-style:none;transition:background 0.2s ease}
.faq-item summary:hover{background:rgba(11,102,255,0.02)}
.faq-item summary::-webkit-details-marker{display:none}
.faq-item summary::after{content:"+";position:absolute;right:20px;font-size:22px;color:var(--accent);transition:transform 0.2s ease}
.faq-item[open] summary::after{transform:rotate(45deg)}
.faq-answer{padding:0 20px 20px;border-top:1px solid rgba(11,38,77,0.05);margin-top:-4px;padding-top:16px}
.faq-answer p{margin:0;font-size:15px;line-height:1.7;color:var(--muted)}
.faq-answer code{background:rgba(11,102,255,0.08);padding:2px 6px;border-radius:4px;font-size:14px;color:var(--accent-2)}

/* Related Section */
.related-section{margin-bottom:48px}
.related-section h2{font-size:28px;color:var(--text);text-align:center;margin-bottom:32px}

/* Scrollbar Styling */
.expansion-container::-webkit-scrollbar{width:8px}
.expansion-container::-webkit-scrollbar-track{background:#f1f5f9;border-radius:4px}
.expansion-container::-webkit-scrollbar-thumb{background:rgba(11,102,255,0.2);border-radius:4px}
.expansion-container::-webkit-scrollbar-thumb:hover{background:rgba(11,102,255,0.3)}

/* Focus states for accessibility */
input:focus-visible, button:focus-visible{outline:2px solid var(--accent);outline-offset:2px}

/* Smooth transitions for interactive elements */
input, button, .card, .faq-item, .step-card{transition:all 0.2s ease}