:root {
    --primary-color: #313132;
    --secondary-color: #0586b8;  
    --background-color: #f6f5f3;
    --container-bg: #ffffff;
    --text-color: #333;
    --border-color: #ddd;
    --header-bg: rgb(254, 254, 254);
    --header-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    --footer-bg: #656768;
    --footer-text: #f5f9f9;
}

*, *::before, *::after { box-sizing: border-box; }

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

a { 
    color: rgb(10, 97, 191); 
    text-decoration: none; 
}
a:hover { 
    text-decoration: underline; 
}


.site-header { 
    background-color: var(--header-bg); 
    padding: 0 1.5rem;   
    box-shadow: var(--header-shadow); 
    position: sticky; 
    top: 0; 
    z-index: 1000; 
    width: 100%;
    left: 0;
    right: 0;
    transform: translateZ(0); 
}


.header-content { 
    display: flex; 
    justify-content: space-between; 
    align-items: center; 
    height: 60px; 
    max-width: 1200px; 
    margin: 0 auto; 
}

.nav-brand { 
    font-size: 1.5rem; 
    font-weight: bold; 
    color: var(--primary-color); 
    text-decoration: none; 
    margin-left: 0;
}


.menu-toggle { 
    display: block; 
    background: none; 
    border: none; 
    font-size: 1.8rem; 
    cursor: pointer; 
    color: var(--primary-color);
    padding: 5px 10px;
    position: fixed;
    top: 15px;
    left: 15px;
    z-index: 1002;
    background-color: #fff;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

.menu-toggle:hover {
    background-color: #f5f5f5;
    transform: scale(1.05);
}


.nav-links-desktop { 
    display: none; 
}
.nav-links-desktop ul { 
    margin: 0; 
    padding: 0; 
    list-style: none; 
    display: flex; 
    gap: 1.5rem; 
}
.nav-links-desktop a { 
    color: var(--text-color); 
    font-weight: 500; 
    padding: 5px 10px;
    border-radius: 4px;
    transition: background-color 0.2s;
}
.nav-links-desktop a:hover {
    background-color: #f0f0f0;
    text-decoration: none;
}


.mobile-nav { 
    position: fixed; 
    top: 0; 
    left: 0; 
    width: 280px; 
    height: 100%; 
    background-color: #fff; 
    box-shadow: 2px 0 10px rgba(0,0,0,0.1); 
    transform: translateX(-100%); 
    transition: transform 0.3s ease-in-out; 
    z-index: 1001; 
    padding: 2rem 1.5rem; 
    overflow-y: auto;
}
.mobile-nav.is-open { 
    transform: translateX(0); 
}

.mobile-nav .close-menu { 
    position: absolute; 
    top: 15px; 
    right: 20px; 
    font-size: 2rem; 
    background: none; 
    border: none; 
    cursor: pointer; 
    color: var(--primary-color);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
}
.mobile-nav .close-menu:hover {
    background-color: #f5f5f5;
}

.mobile-nav ul { 
    list-style: none; 
    padding: 40px 0 0 0; 
    margin: 0; 
}
.mobile-nav li a { 
    display: block; 
    padding: 1rem 0; 
    font-size: 1.2rem; 
    color: var(--text-color); 
    text-decoration: none; 
    border-bottom: 1px solid var(--border-color); 
    transition: padding-left 0.2s;
}
.mobile-nav li a:hover {
    padding-left: 10px;
    color: var(--secondary-color);
}

.nav-overlay { 
    position: fixed; 
    top: 0; 
    left: 0; 
    width: 100%; 
    height: 100%; 
    background-color: rgba(0,0,0,0.5); 
    z-index: 1000; 
    opacity: 0; 
    visibility: hidden; 
    transition: opacity 0.3s ease-in-out; 
}
.nav-overlay.is-open { 
    opacity: 1; 
    visibility: visible; 
}

.countdown-nav-btn {
    background: linear-gradient(135deg, #2563eb, #1d4ed8);
    color: white !important;
    padding: 8px 16px !important;
    border-radius: 6px;
    font-weight: 600;
    transition: all 0.3s;
}
.countdown-nav-btn:hover {
    background: linear-gradient(135deg, #1d4ed8, #1e40af);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.2);
    text-decoration: none !important;
}


.breadcrumb-container {
    max-width: 940px; 
    margin: 0 auto;
    padding: 0 8px; 
    line-height: 1.8;
}
.breadcrumb {
    padding: 10px 0;
    list-style: none;
    display: flex;
    font-size: 0.95em;
    margin-bottom: 15px;
}
.breadcrumb li {
    display: flex;
    align-items: center;
}
.breadcrumb li + li::before {
    content: "›";   
    margin: 0 10px; 
    color: #999;    
    font-weight: bold;
}
.breadcrumb a {
    text-decoration: none;
    color: #007bff;
}
.breadcrumb a:hover {
    text-decoration: underline;
}
.breadcrumb-item.active {
    color: #6c757d;
    pointer-events: none;
}


.container { 
    max-width: 940px; 
    margin: 1rem auto; 
    padding: 0.5rem .8rem; 
    width: 95%; 
    flex-grow: 1; 
}


h1, h2 { 
    text-align: left; 
    color: var(--primary-color); 
}
h1 { 
    font-size: 1.8rem; 
    margin-bottom: 0.5rem; 
}
h2 { 
    font-size: 1.5rem; 
    margin-top: 2.5rem; 
    margin-bottom: 1rem; 
    border-bottom: 2px solid var(--border-color); 
    padding-bottom: 0.5rem; 
}

.intro-paragraph { 
    text-align: left; 
    font-size: 1.1rem; 
    color: #555; 
    margin: 0 auto 2rem; 
    max-width: 900px; 
}


.calculation-block { 
    padding: 1rem; 
    background-color: #fdfdfd; 
    border: 1px solid var(--border-color); 
    border-radius: 5px; 
    margin-bottom: 2rem; 
}
.form-row { 
    display: flex; 
    flex-direction: column; 
    gap: 1rem; 
}
.form-row input, .form-row select { 
    padding: 0.75rem; 
    font-size: 1rem; 
    border: 1px solid var(--border-color); 
    border-radius: 5px; 
    width: 100%; 
}
.form-actions { 
    text-align: center; 
    margin-top: 1rem; 
}
#calculateBtn { 
    width: 100%; 
    padding: 0.8rem 1rem; 
    font-size: 1.1rem; 
    font-weight: bold; 
    color: #fff; 
    background-color: var(--secondary-color); 
    border: none; 
    border-radius: 5px; 
    cursor: pointer; 
    transition: background-color 0.2s ease; 
}
#calculateBtn:hover { 
    background-color: var(--primary-color); 
}


.descriptive-answer-box { 
    background-color: #fdfdfd; 
    border: 1px solid var(--border-color); 
    border-radius: 8px; 
    padding: 1rem; 
    margin: 2rem auto; 
    text-align: left; 
}
.answer-table { 
    width: 100%; 
    border-collapse: collapse; 
}
.answer-table td { 
    padding: 0.8rem 0; 
    vertical-align: top; 
    border-bottom: 1px solid #e9ecef; 
}
.answer-table tr:last-child td { 
    border-bottom: none; 
}
.answer-table td:first-child { 
    font-weight: 600; 
    color: var(--primary-color); 
    width: 130px; 
    padding-right: 1.5rem; 
}


.site-footer {
    background-color: #343435;
    margin-top: 4rem;
    padding: 3rem 1.5rem; 
    border-top: 1px solid var(--border-color);
}
.footer-content {
    max-width: 1200px;
    margin: 0 auto; 
    display: flex;
    justify-content: center; 
    flex-wrap: wrap;
    gap: 4rem; 
}
.footer-column {
    flex: 0 1 300px; 
}
.footer-column h4 {
    font-size: 1.1rem;
    color: #ffffff;
    margin-top: 0;
    margin-bottom: 1.25rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border-color);
}
.footer-column ul {
    list-style: none;
    padding: 0;
    margin: 0;
}
.footer-column ul li {
    margin-bottom: 0.8rem;
}
.site-footer a {
    color: #ffffff;
    text-decoration: none;
    transition: color 0.2s ease-in-out;
}
.site-footer a:hover {
    color: #cccccc;
    text-decoration: underline;
}
.footer-bottom {
    max-width: 1200px;
    margin: 2rem auto 0; 
    padding-top: 1.5rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
    font-size: 1rem;
    color: #ffffff;
    opacity: 0.8;
}

@media (max-width: 900px) {
    .footer-content {
        gap: 2rem; 
    }
    .footer-column {
        flex-basis: 250px; 
    }
}

@media (max-width: 767px) {
    .menu-toggle {
        top: 10px;
        left: 10px;
        width: 50px;
        height: 45px;
        font-size: 1.6rem;
        background-color: var(--header-bg);
    }

    .site-header {
        padding: 0 12px;
    }

    .header-content {
        justify-content: flex-end;
        max-width: 100%;
    }

    .nav-brand {
        text-align: right;
        width: 100%;
        padding-right: 15px;
        padding-left: 70px;
        font-size: 1.4rem;
        overflow: hidden;
        text-overflow: ellipsis;
        white-space: nowrap;
    }

    .footer-content {
        flex-direction: column;
        align-items: center;
        gap: 2.5rem;
    }
    .footer-column {
        text-align: center;
        width: 100%;
        max-width: 300px;
    }
    .footer-column h4 {
        text-align: center;
    }
}

@media (max-width: 480px) {
    .nav-brand {
        font-size: 1.2rem;
        padding-left: 65px;
        padding-right: 10px;
    }
    
    .menu-toggle {
        top: 8px;
        left: 8px;
        width: 45px;
        height: 40px;
        font-size: 1.5rem;
    }
}

@media (min-width: 768px) {
    .menu-toggle { 
        display: none !important; 
    }

    .site-header {
        padding: 0 1.5rem; 
    }

    .nav-links-desktop { 
        display: block; 
    }

    .form-row { 
        flex-direction: row; 
    }
    .form-row input { 
        flex: 1; 
    }
    .form-row select { 
        flex: 2; 
    }
    #calculateBtn { 
        width: auto; 
        min-width: 200px; 
    }
}