:root {
    --dark-bg: #121212;
    --dark-card: #1e1e1e;
    --dark-card-header: #000000;
    --accent: rgba(134, 31, 31, 0.8);
    --text: #f0f0f0;
    --subtle-text: #c0c0c0;
    --matrix-border: #000000;
}

body {
    background-color: var(--dark-bg);
    color: var(--text);
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 0;
}

.container-fluid {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

header h1 {
    font-weight: 600;
    color: var(--text);
    margin-bottom: 10px;
    font-size: 2.5rem;
}

header .lead {
    color: var(--subtle-text);
    font-size: 1.2rem;
}

.nav-tabs {
    border-bottom: none;
    padding-bottom: 0;
    margin-bottom: 0;
}

.nav-tabs .nav-link {
    color: var(--subtle-text);
    border: none;
    padding: 10px 20px;
    margin-right: 5px;
    border-radius: 8px 8px 0 0;
    transition: all 0.3s ease;
    background-color: rgba(30, 30, 30, 0.5);
}

.nav-tabs .nav-link:hover {
    color: var(--text);
    background-color: rgba(0, 0, 0, 0.7);
}

.nav-tabs .nav-link.active {
    background-color: var(--dark-card);
    color: var(--text);
    border: none;
    font-weight: 500;
    position: relative;
}

.nav-tabs .nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    right: 0;
    height: 2px;
    background-color: var(--dark-card);
}

.tab-content {
    background-color: var(--dark-card);
    border-radius: 0 8px 8px 8px;
    padding: 25px !important;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    margin-top: 0;
}

.card {
    background-color: #141414;
    border: none;
    border-radius: 8px;
    margin-bottom: 20px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    height: 100%;
}

.card-header {
    background-color: var(--dark-card-header);
    color: var(--text);
    border-bottom: none;
    padding: 15px 20px;
    border-radius: 8px 8px 0 0 !important;
}

.card-header h5 {
    margin: 0;
    font-weight: 500;
}

.card-body {
    padding: 20px;
}

.form-label {
    color: var(--subtle-text);
    margin-bottom: 10px;
    font-weight: 500;
}

.form-control, .input-group-text {
    background-color: var(--dark-bg);
    border: 1px solid #000000;
    color: var(--text);
    border-radius: 4px;
}

.form-control:focus {
    background-color: var(--dark-bg);
    color: var(--text);
    border-color: var(--accent);
    box-shadow: 0 0 0 0.2rem rgba(233, 69, 96, 0.25);
}

.btn-primary {
    background-color: rgba(134, 31, 31, 0.8);
    border-color: rgba(134, 31, 31, 0.8);
    transition: all 0.2s ease;
}

.btn-primary:hover, .btn-primary:focus {
    background-color: rgba(134, 31, 31, 0.8);
    border-color: rgba(134, 31, 31, 0.8);
    transform: translateY(-1px);
}

.btn-success {
    background-color: var(--accent);
    border-color: var(--accent);
    color: white;
    transition: all 0.2s ease;
}

.btn-success:hover, .btn-success:focus {
    background-color: rgba(134, 31, 31, 0.8);
    border-color: rgba(134, 31, 31, 0.8);
    color: white;
    transform: translateY(-1px);
}

.matrix-container, .vectors-container {
    margin: 20px 0;
    overflow-x: auto;
}

.matrix-table {
    border-collapse: collapse;
    border-spacing: 0;
    margin: 0 auto;
}

.matrix-table input {
    width: 70px;
    height: 40px;
    text-align: center;
    background-color: gray;
    border: 1px solid var(--matrix-border);
    color: var(--text);
    border-radius: 4px;
    transition: all 0.2s ease;
}

.matrix-table input:focus {
    background-color: rgba(26, 26, 46, 1);
    border-color: var(--accent);
    outline: none;
    box-shadow: 0 0 0 2px rgba(233, 69, 96, 0.15);
}

.result-container {
    min-height: 200px;
    padding: 15px;
    background-color: rgba(20, 20, 20, 0.6);
    border-radius: 4px;
    position: relative;
    box-shadow: inset 0 0 8px rgba(0, 0, 0, 0.2);
}

.step-container {
    padding: 10px;
}

.step-description {
    margin-bottom: 15px;
    padding: 10px;
    background-color: rgba(0,0,0,0.1);
    border-radius: 4px;
    line-height: 1.6;
}

.step-description b {
    display: block;
    margin-bottom: 8px;
    font-size: 1.1rem;
}

.step-description .formula {
    font-size: 1.15rem;
    font-family: 'Courier New', Courier, monospace;
    display: inline-block;
    margin-top: 4px;
    margin-bottom: 4px;
    padding: 2px 5px;
}

.step-description div[style*="margin-left"] {
    margin-top: 10px !important;
    padding-left: 10px;
    border-left: 2px solid rgba(134, 31, 31, 0.3);
}

#ortho-step-vectors .result-vector {
    margin-bottom: 15px;
    padding: 10px;
    background-color: rgba(0,0,0,0.15);
    border-radius: 4px;
}

#ortho-step-vectors .result-matrix-row {
    margin-top: 5px;
}

#ortho-step-vectors .result-matrix-cell {
    margin-right: 10px;
    padding: 5px 8px;
    min-width: 60px;
    background-color: rgba(255, 255, 255, 0.05);
    border-radius: 3px;
}

.step-navigation {
    margin-top: 20px;
}

.result-matrix {
    margin: 20px auto;
    border-left: 2px solid var(--accent);
    border-right: 2px solid var(--accent);
    padding: 0 15px;
}

.result-matrix-row {
    display: flex;
    justify-content: center;
}

.result-matrix-cell {
    padding: 8px 12px;
    min-width: 50px;
    text-align: center;
}

/* Style for highlighted pivot elements */
.pivot-highlight {
    background-color: rgba(220, 53, 69, 0.35) !important; /* Red background */
    border: 2px solid rgba(200, 30, 45, 0.9) !important;  /* Darker red border */
    border-radius: 4px;
    font-weight: bold;
    box-shadow: 0 0 6px rgba(220, 53, 69, 0.5); /* Red glow */
    color: #ffffff !important; /* Ensure text is readable */
}

/* Style for the separator line in augmented matrices */
.augmented-separator {
    border-right: 2px solid rgba(200, 200, 200, 0.6) !important; /* Visible gray line */
    padding-right: 10px !important; /* Add some space after the cell before the line */
    margin-right: 5px !important; /* Add some space after the line before the next cell */
}

.placeholder-text {
    color: var(--subtle-text);
    font-style: italic;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.result-message {
    margin-top: 20px;
    padding: 15px;
    background-color: rgba(20, 20, 20, 0.5);
    border-radius: 4px;
    white-space: pre-wrap;
    border-left: 3px solid var(--accent);
}

.eigenvalue-section {
    margin-bottom: 25px;
    padding: 15px;
    background-color: rgba(20, 20, 20, 0.5);
    border-radius: 4px;
    border-left: 3px solid var(--accent);
}

.eigenvector-item {
    margin-bottom: 10px;
}

.basis-section {
    margin-bottom: 25px;
    padding: 15px;
    background-color: rgba(20, 20, 20, 0.5);
    border-radius: 4px;
    border-left: 3px solid var(--accent);
}

.basis-summary {
    background-color: rgba(20, 20, 20, 0.5);
    padding: 15px;
    border-radius: 4px;
    margin-bottom: 20px;
    border-left: 3px solid var(--accent);
}

.vector-label, .vector-item {
    color: var(--text);
}

.alert-danger {
    background-color: rgba(220, 53, 69, 0.2);
    color: #f8d7da;
    border-color: rgba(220, 53, 69, 0.4);
}

@media (max-width: 768px) {
    .tab-content {
        padding: 15px !important;
    }
    
    .card-body {
        padding: 15px;
    }
}

/* Style for the cell needing a right border separator */
.rhs-separator {
    border-right: 1px solid var(--accent) !important; /* Thin accent color line */
    padding-right: 8px !important; /* Space BEFORE the line */
}

/* Add space AFTER the line by padding the NEXT cell */
.rhs-separator + td {
    padding-left: 8px !important; /* Space AFTER the line */
}

.result-matrix {
    display: inline-block;
} 

/* Remove spinner arrows from all number inputs */
input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
    -webkit-appearance: none !important;
    margin: 0 !important;
}

input[type="number"] {
    -moz-appearance: textfield !important; /* Firefox */
    appearance: textfield !important;
}