/* --- CSS Variables for Easy Theming --- */
:root {
    --primary-color: #2563eb; /* A modern, educational blue */
    --primary-hover: #1d4ed8;
    --bg-color: #f8fafc;
    --panel-bg: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --radius: 12px;
}

/* --- Global Reset & Typography --- */
* {
    box-sizing: border-box; 
    /* Crucial for responsive design */
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    margin: 0;
    padding: 20px;
    line-height: 1.5;
}

/* --- Layout Container --- */
.container {
    display: flex;
    flex-direction: row; /* Side by side on desktop */
    gap: 25px;
    max-width: 1200px;
    margin: 0 auto;
    align-items: flex-start;
}

.control-panel, .results-panel {
    background: var(--panel-bg);
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

.control-panel {
    flex: 1;
    min-width: 320px;
    position: sticky; /* Keeps controls visible while scrolling results on desktop */
    top: 20px; 
}

.results-panel {
    flex: 2;
    min-width: 0; /* Prevents flex items from overflowing */
}

/* --- Headings --- */
h2 {
    margin-top: 0;
    color: var(--text-main);
    font-size: 1.5rem;
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 12px;
    margin-bottom: 24px;
}

h3 {
    font-size: 1.1rem;
    color: var(--text-main);
}

/* --- Inputs & Forms --- */
.input-group {
    margin-bottom: 20px;
}

label {
    display: block;
    font-weight: 600;
    margin-bottom: 8px;
    font-size: 0.9rem;
    color: var(--text-main);
}

input[type="text"], input[type="number"] {
    width: 100%;
    padding: 12px;
    border: 1.5px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

input[type="text"]:focus, input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.flex-inputs {
    display: flex;
    gap: 15px;
}

.methods-group {
    background: var(--bg-color);
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 25px;
    border: 1px solid var(--border-color);
}

.methods-group label {
    font-weight: normal;
    font-size: 1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 10px;
}

/* --- Buttons --- */
button {
    width: 100%;
    padding: 14px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
}

button:hover {
    background-color: var(--primary-hover);
}

button:active {
    transform: scale(0.98);
}

/* --- Tables --- */
.table-wrapper {
    overflow-x: auto; /* Allows horizontal scroll on small screens */
    margin-top: 20px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

table {
    width: 100%;
    border-collapse: collapse;
    white-space: nowrap; /* Keeps data on one line */
}

th, td {
    padding: 14px 16px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

th {
    background-color: var(--bg-color);
    font-weight: 600;
    color: var(--text-muted);
}

tbody tr:hover {
    background-color: rgba(248, 250, 252, 0.8);
}

#graph-container {
    margin-top: 30px;
    min-height: 300px;
}

/* =========================================
   MOBILE RESPONSIVENESS (Media Queries)
   ========================================= */
@media (max-width: 850px) {
    .container {
        flex-direction: column; /* Stack panels vertically */
    }

    .control-panel {
        width: 100%;
        position: static; /* Remove sticky on mobile */
    }

    .results-panel {
        width: 100%;
        overflow: scroll;
    }

    /* Stack the side-by-side inputs on very small screens */
    .flex-inputs {
        flex-direction: column;
        gap: 10px;
    }
}

/* --- Graph Container Mobile Fixes --- */
#graph-container {
    margin-top: 30px;
    width: 100%; /* Force it to stay within parent */
    max-width: 100%;
}

#plotly-chart {
    width: 100%;
    min-height: 350px;
    /* This prevents Plotly from breaking the container width on resize */
    overflow: hidden; 
}

/* Ensure the wrapper doesn't cause horizontal scrolling on the whole page */
.results-panel {
    max-width: 100%;
    overflow-x: hidden; 
}

/* Adjust the table wrapper inside the results panel so tables scroll, but the panel stays fixed */
.table-wrapper {
    width: 100%;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch; /* Smooth scrolling on iOS */
}


/* --- Linear Matrix Grid Styles --- */
.matrix-row {
    display: flex;
    align-items: center;
    gap: 5px;
    margin-bottom: 10px;
    flex-wrap: nowrap;
}

.matrix-input {
    width: 60px !important; /* Force smaller boxes for the matrix */
    padding: 8px !important;
    text-align: center;
}

.matrix-label {
    font-weight: bold;
    color: var(--primary-color);
    min-width: 30px;
}

.equals-sign {
    font-weight: bold;
    margin: 0 10px;
}

/* Scrollable container if the matrix gets too big (like 5x5 or 6x6) */
#matrix-container {
    overflow-x: auto;
    padding-bottom: 10px;
    border: 1px dashed var(--border-color);
    padding: 15px;
    border-radius: 8px;
    background: #fafafa;
    margin-top: 15px;
}





/* Tiny tweaks for extra small phones */
@media (max-width: 400px) {
    body {
        padding: 10px;
    }
    
    .control-panel, .results-panel {
        padding: 20px;
    }
}