/* --- Global Styles --- */
        body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif; background-color: #f8f9fc; color: #333; margin: 0; line-height: 1.7; position: relative; overflow-x: hidden; scroll-behavior: smooth; }
        body::before, body::after { content: ''; position: absolute; border-radius: 50%; z-index: -1; background: radial-gradient(circle, rgba(237, 234, 255, 0.6) 0%, rgba(248, 249, 252, 0) 70%); }
        body::before { top: 120px; right: -150px; width: 400px; height: 400px; }
        body::after { top: 250px; left: -200px; width: 500px; height: 500px; }
        .container { max-width: 1000px; margin: 0 auto; padding: 20px; }
        .card { background-color: #fff; border-radius: 12px; padding: 32px 40px; box-shadow: 0 4px 25px rgba(0, 0, 0, 0.06); margin-bottom: 30px; }
        h1, h2, h3 { color: #333; text-align: center; }
        h1 { font-size: 48px; color: #7b61ff; margin-bottom: 10px; }
        .main-subtitle { text-align: center; font-size: 18px; color: #666;  }
        h2 { font-size: 28px; margin-top: 50px; margin-bottom: 20px; }
        h3 { font-size: 22px; text-align: center; margin-top: 0; color: #333; }
        h4 { font-size: 18px; font-weight: bold; margin-top: 25px; margin-bottom: 10px; text-align: center; }
        
        /* --- Calculator Styles --- */
        .form-group { display: flex; align-items: center; margin-bottom: 20px; position: relative; }
        .form-group label { width: 150px; color: #555; font-size: 16px; flex-shrink: 0; }
        .form-group input[type="number"] { flex: 1; padding: 12px; border: 1px solid #ddd; border-radius: 6px; font-size: 16px; box-sizing: border-box; }
        .form-group .unit { margin-left: 10px; font-size: 16px; color: #555; }
        .button-group { display: flex; gap: 15px; margin-top: 15px; }
        .btn-calculate, .btn-reset { width: 100%; padding: 14px; color: #fff; border: none; border-radius: 8px; font-size: 18px; font-weight: 500; cursor: pointer; transition: all 0.3s; }
        .btn-calculate { background-color: #7b61ff; }
        .btn-calculate:hover { background-color: #6a50e0; transform: translateY(-2px); box-shadow: 0 4px 15px rgba(123, 97, 255, 0.4); }
        .btn-reset { background-color: #6c757d; }
        .btn-reset:hover { background-color: #5a6268; }
        
        /* --- Results Area --- */
        #results-area { background: linear-gradient(180deg, #ffffff 0%, #f8f9fc 100%); padding: 50px 0; margin-top: 40px; display: none; box-shadow: 0 -5px 25px rgba(0,0,0,0.05); }
        .result-summary { display: flex; justify-content: space-around; text-align: center; margin-bottom: 30px; padding-bottom: 30px; border-bottom: 1px solid #eee; flex-wrap: wrap; gap: 20px; }
        .result-summary-item { background: #fff; border: 1px solid #e9e9e9; box-shadow: 0 2px 8px rgba(0,0,0,0.04); padding: 20px; border-radius: 12px; flex: 1; min-width: 220px; transition: transform 0.2s, box-shadow 0.2s; }
        .result-summary-item:hover { transform: translateY(-3px); box-shadow: 0 4px 15px rgba(0,0,0,0.08); }
        .result-summary-item .label { font-size: 15px; color: #666; margin-bottom: 8px; }
        .result-summary-item .value { font-size: 28px; font-weight: bold; color: #7b61ff; }
        #descriptive-summary { font-size: 16px; line-height: 1.6; color: #333; background-color: #e9e6ff; border-left: 4px solid #7b61ff; padding: 15px 20px; margin: 35px auto; border-radius: 0 8px 8px 0; max-width: 90%; }
        .chart-container { background: #fff; padding: 25px; border-radius: 12px; box-shadow: 0 4px 25px rgba(0,0,0,0.06); margin-top: 20px; }
        .table-responsive-wrapper { overflow-x: auto; -webkit-overflow-scrolling: touch; margin-top: 15px; }
        #results-table { white-space: nowrap; width: 100%; min-width: 600px; border-collapse: collapse; }
        #results-table th, #results-table td { padding: 12px 15px; text-align: right; border-bottom: 1px solid #eee; }
        #results-table th { color: #333; font-weight: bold; background-color: #f0f2f5; text-align: right; }
        #results-table th:first-child, #results-table td:first-child { text-align: center; }

        /* --- Content Sections --- */
        .explanation-card { text-align: left; }
        .two-column-layout { display: flex; align-items: center; gap: 50px; margin-top: 30px; }
        .two-column-layout .text-column { flex: 1; }
        .two-column-layout .image-column { flex-shrink: 0; width: 100%; max-width: 380px; }
        .content-image { max-width: 100%; height: auto; display: block; border-radius: 12px; box-shadow: 0 4px 20px rgba(0, 0, 0, 0.07); }
        
        /* --- Formula Block Styles --- */
        .formula-container { display: flex; flex-direction: column; gap: 25px; margin-top: 20px; }
        .formula-item { background-color: #f8f9fa; border-radius: 8px; padding: 25px; border: 1px solid #eee; }
        .formula-item h4 { text-align: left; margin-top: 0; color: #7b61ff; }
        .formula-display { font-family: 'Courier New', Courier, monospace; font-size: 22px; font-weight: bold; color: #333; background: #fff; padding: 15px; border-radius: 6px; text-align: center; margin: 10px 0; border: 1px solid #e9e9e9; }
        .variables-list { list-style: none; padding: 0; text-align: left; margin-top: 15px; }
        .variables-list li { display: flex; align-items: flex-start; margin-bottom: 12px; font-size: 16px; }
        .variables-list li strong { display: inline-block; width: 25px; font-family: 'Courier New', Courier, monospace; font-size: 18px; color: #333; flex-shrink: 0; }
        .example-box { background-color: #e9e6ff; border-left: 4px solid #7b61ff; padding: 20px 25px; margin-top: 30px; border-radius: 0 8px 8px 0; text-align: left; }
        .example-box h4 { text-align: left; margin-top: 0; }

        /* --- FAQ Section --- */
        .faq-item { border-bottom: 1px solid #eee; padding: 15px 0; }
        .faq-item:last-child { border-bottom: none; }
        .faq-item summary { font-weight: bold; font-size: 18px; cursor: pointer; position: relative; padding-right: 30px; list-style: none; color: #333; transition: color 0.2s; }
        .faq-item summary::-webkit-details-marker { display: none; }
        .faq-item summary:hover { color: #7b61ff; }
        .faq-item summary::after { content: '+'; position: absolute; right: 5px; top: 50%; transform: translateY(-50%); font-size: 24px; font-weight: 300; color: #7b61ff; transition: transform 0.2s; }
        .faq-item[open] > summary::after { transform: translateY(-50%) rotate(45deg); }
        .faq-answer { padding: 15px 5px 0 5px; line-height: 1.7; color: #555; }

        /* --- Header & Navigation --- */
        .site-header { position: sticky; top: 0; left: 0; width: 100%; z-index: 1000; background-color: rgba(255, 255, 255, 0.85); backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px); box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05); }
        .header-container { display: flex; justify-content: space-between; align-items: center; height: 70px; }
        .main-nav { display: flex; align-items: center; gap: 15px; }
        .main-nav a { color: #555; text-decoration: none; padding: 8px 12px; border-radius: 6px; font-size: 16px; transition: background-color 0.2s, color 0.2s; }
        .main-nav a:hover { background-color: #f0f0f0; color: #333; }
        .main-nav .nav-item.active > a { color: #7b61ff; font-weight: bold; }
        .dropdown { position: relative; display: inline-block; }
        .dropdown-content { display: none; position: absolute; background-color: #ffffff; min-width: 240px; box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.1); border-radius: 8px; z-index: 1; margin-top: 10px; padding: 8px 0; border: 1px solid #eee; }
        .dropdown-content a { color: #333; padding: 12px 20px; text-decoration: none; display: block; }
        .dropdown-content a:hover { background-color: #f1f1f1; }
        .dropdown:hover .dropdown-content { display: block; }
        .dropdown .dropbtn { display: flex; align-items: center; gap: 5px; cursor: pointer; }
        .dropdown .dropbtn::after { content: '▼'; font-size: 10px; }

        .nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 10px; z-index: 1001; }
        .hamburger { display: block; position: relative; width: 24px; height: 2px; background-color: #333; transition: all 0.3s ease-in-out; }
        .hamburger::before, .hamburger::after { content: ''; position: absolute; left: 0; width: 100%; height: 2px; background-color: #333; transition: all 0.3s ease-in-out; }
        .hamburger::before { top: -8px; } .hamburger::after { bottom: -8px; }
        .nav-open .hamburger { background-color: transparent; }
        .nav-open .hamburger::before { transform: translateY(8px) rotate(45deg); }
        .nav-open .hamburger::after { transform: translateY(-8px) rotate(-45deg); }

        /* --- Footer --- */
        .site-footer-full { background-color: #222; color: #ccc; padding: 60px 0; margin-top: 50px; }
        .footer-bottom { display: flex; justify-content: space-between; align-items: center; margin-top: 40px; padding-top: 20px; border-top: 1px solid #444; flex-wrap: wrap; gap: 15px; }
        .footer-bottom p { margin: 0; }
        .footer-links a { color: #ccc; text-decoration: none; margin: 0 10px; }

        /* --- Media Queries --- */
        @media (max-width: 900px) {
            .two-column-layout { flex-direction: column; text-align: center; }
            .two-column-layout .text-column { order: 2; }
            .two-column-layout .image-column { order: 1; margin-bottom: 30px; max-width: 450px; }
            .two-column-layout .text-column, .formula-item, .example-box { text-align: center; }
            .formula-item h4, .variables-list li, .example-box h4 { text-align: left; }
        }
        
        @media (max-width: 800px) {
            h1 { font-size: 36px; }
            .card { padding: 24px; }
            .result-summary { flex-direction: column; gap: 15px; }
            
            .calculator-card .form-group { flex-direction: column; align-items: flex-start; margin-bottom: 25px; }
            .calculator-card .form-group label { width: auto; margin-bottom: 8px; font-weight: 500; }
            .calculator-card .form-group input[type="number"] { width: 100%; }
            .calculator-card .form-group .unit { position: absolute; right: 15px; bottom: 13px; color: #888; pointer-events: none; margin-left: 0; }
            #principal, #rate, #years { padding-right: 40px !important; }

            /* Mobile Nav */
            .main-nav { position: fixed; top: 0; right: -100%; width: 80%; max-width: 320px; height: 100vh; background-color: #fff; box-shadow: -5px 0 15px rgba(0,0,0,0.1); transition: right 0.3s ease-in-out; display: flex; flex-direction: column; justify-content: center; align-items: center; padding-top: 70px; gap: 10px; }
            .nav-open .main-nav { right: 0; }
            .main-nav a { font-size: 20px; width: 100%; text-align: center; }
            .main-nav .nav-item { width: 100%; }
            .dropdown { width: 100%; }
            .dropdown .dropbtn { justify-content: center; padding: 12px 20px; }
            .dropdown:hover .dropdown-content, .dropdown:focus-within .dropdown-content { display: none; }
            .nav-open .dropdown-content { display: block; position: static; background: #f9f9f9; box-shadow: none; border: none; width: 100%; text-align: center; }
            .nav-open .dropdown-content a { font-size: 18px; color: #555; }
            .nav-toggle { display: block; }
            .footer-bottom { justify-content: center; text-align: center; }
        }