/* General Layout */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    margin: 0;
    padding: 0;
    background-color: #f8f9fa;
}

/* --- Layout Container --- */
.main-layout-wrapper {
    display: flex;
    flex-direction: column; /* Mobile Default: Ad on Top */
    gap: 20px;
    padding: 15px;
    width: 100%;
    box-sizing: border-box; /* Ensures padding doesn't overflow width */
}

/* --- Ad Container --- */
.adsense-container {
    width: 100%;
    text-align: center;
    /* Parent does NOT get sticky. It just holds the space. */
    flex-shrink: 0; 
}

/* This wrapper handles the sticking */
.ad-sticky-wrapper {
    position: sticky;
    top: 20px; /* Sticks 20px from top of viewport */
    height: auto;
}

.ad-placeholder {
    background: #ebebeb;
    border: 1px solid #ddd;
    min-height: 250px; 
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: #666;
    width: 100%;
    max-width: 300px; /* Prevents ad from getting too huge on mobile */
    margin: 0 auto;
}

.calculator-content {
    flex: 1;
    width: 100%;
    max-width: 900px;
    /* Ensure it doesn't shrink below usability before wrapping */
    min-width: 0; 
}

/* --- Desktop Layout Switch (>= 720px) --- */
@media (min-width: 720px) {
    .main-layout-wrapper {
        flex-direction: row; 
        /* align-items: stretch is default.
           This makes the sidebar as tall as the content, 
           allowing the sticky wrapper to slide down. */
        justify-content: center; /* Centers the whole block if screen is huge */
        max-width: 100%; 
        gap: 20px; 
    }

    .adsense-container {
        /*  Fixed 300px width */
        width: 300px; 
        flex: 0 0 300px; 
        margin-bottom: 0;
    }

    .ad-placeholder {
        min-height: 600px; /* Skyscraper height */
    }

    .calculator-content {
        /*  Min-width 400px before wrap logic would apply,
           but since we are in a media query, this ensures sturdiness */
        min-width: 400px; 
        margin: 0; 
    }
}

/* --- Headings & Global UI --- */
h3 {
    border-bottom: 2px solid #0056b3;
    padding-bottom: 5px;
    color: #0056b3;
    margin-top: 30px;
}

h4.pipe-label {
    margin: 0;
    color: #0056b3;
    font-size: 1em;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* --- Pipe Group Cards --- */
.pipe-row {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    margin-bottom: 25px;
    align-items: stretch;
}

.pipe-group {
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    padding: 15px;
    flex: 2; 
    min-width: 280px; 
    display: grid;
    grid-template-columns: max-content 1fr max-content 1fr;
    align-items: center;
    gap: 10px;
    border: 1px solid #ddd;
}

.name-row, .header-row {
    grid-column: span 4;
}

.header-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid #eee;
    margin-bottom: 5px;
    padding-bottom: 5px;
}

.name-row {
    display: flex;
    align-items: center;
    gap: 10px;
}

/* --- Result Column (Strict 130px) --- */
.result-column {
    width: 130px; /* FIXED WIDTH */
    display: flex;
    flex-direction: column;
    justify-content: center;
    background: #eef4ff;
    padding: 10px;
    text-align: center;
    border-radius: 4px;
    flex-shrink: 0; 
}

.result-column .label {
    font-size: 0.75em; 
    color: #666;
    margin-bottom: 2px;
    text-transform: uppercase;
}

.result-column .value {
    font-size: 1.2em; 
    font-weight: bold;
    color: #0056b3;
}

/* --- Form Elements --- */
label {
    font-size: 0.9em;
    font-weight: 600;
    color: #555;
}

select, input[type="number"], input[type="text"] {
    padding: 6px 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
    font-size: 0.9em;
    box-sizing: border-box; /* Prevents padding from blowing out width */
}

input[type="number"] {
    width: 100%; /* Let grid control width */
    max-width: 80px;
}

.p_od_disp, .f_od_disp {
    background: #e9ecef;
    padding: 2px 6px;
    border-radius: 4px;
    text-align: center;
    font-family: monospace;
    font-size: 1em;
}

/* --- Buttons --- */
button {
    cursor: pointer;
    font-weight: 600;
    padding: 8px 16px;
    border-radius: 4px;
    border: none;
    transition: all 0.2s;
}

#addPipeBtn {
    background-color: #28a745;
    color: white;
    padding: 0.8em 1em; 
    font-size: 1em;
}

#addPipeBtn:hover {
    background-color: #218838;
}

.remove-btn {
    background-color: transparent;
    border: 1px solid #dc3545 !important;
    font-size: 0.8em;
    color: #dc3545;
}

.remove-btn:hover {
    background-color: #dc3545;
    color: white !important;
}

/* The main container */
.button-group {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 20px;
}

/* The magic wrapper that keeps buttons together */
.button-pair {
    display: flex;
    flex: 1;
    gap: 10px;
    /* This min-width ensures that if the screen is narrower than 
       roughly two buttons, the whole pair drops to the next line. */
    min-width: 300px; 
}

.toolbar-btn {
    flex: 1; 
    font-size: 1.1em;
    padding: 12px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    color: white;
    transition: background 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    text-decoration: none; 
    background-color: #28a745;
    /* Removed individual min-width to let the pair handle logic */
}
.toolbar-btn:hover {
    background-color: #218838;
}

.btn-persistence {
    background-color: #6f42c1; 
}
.btn-persistence:hover {
    background-color: #59359a;
}

.formula-container {
    background-color: #f8f9fa;
    border-left: 5px solid #007bff; /* Professional blue accent */
    padding: 20px;
    margin: 20px 0;
    border-radius: 4px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    overflow-x: auto; /* Adds a scrollbar if the formula is too wide for mobile */
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.formula-label {
    font-weight: bold;
    color: #495057;
    margin-bottom: 10px;
    display: block;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}


/* --- Results Footer --- */
#gap {
    font-size: 1.1em;
    font-weight: bold;
    color: #0056b3;
    width: 80px;
}

#totalSpacingDisplay {
    background: #333;
    color: #ffffff !important;
    padding: 15px;
    border-radius: 8px;
    text-align: center;
    letter-spacing: 1px;
    margin-top: 20px;
}

/* Styling for images in the User Guide */
.calculator-content img {
    max-width: 100%;    /* Prevents image from being wider than the screen */
    height: auto;       /* Maintains aspect ratio */
    display: block;     /* Removes weird bottom gaps */
    margin: 15px auto;  /* Centers the image and adds space top/bottom */
    border: 1px solid #ddd; 
    border-radius: 4px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1); /* Adds a subtle "pop" */
}

site-footer {
    text-align: center;
    margin-top: 40px;
    padding-bottom: 20px;
}

.site-footer a {
    font-size: 11px; /* Makes it smaller */
    color: #999;    /* Light gray to be less prominent */
    text-decoration: none; /* Removes the underline */
    transition: color 0.3s ease;
}

.site-footer a:hover {
    color: #555;    /* Slightly darker on hover for usability */
    text-decoration: underline;
}