/* Universal Styles */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;600;700&display=swap');

body {
    font-family: 'Inter', sans-serif;
    /* Universal background: seamless blend of black, brown, and white */
    background: linear-gradient(to right, #a08e8e 0%, #b5b8d2 50%, #708f71 100%);
    color: #06c8fe; /* Default text color for body */
    margin: 0;
    padding: 0;
}

/* Header, Nav Bar, and Main Content Area Background */
/* Smooth gradient transparent grey */
.nav-background,
.main-content-area,
.content-section-background {
    background: rgba(128, 128, 128, 0.1); /* Slightly transparent grey */
    backdrop-filter: blur(5px); /* Optional: adds a subtle blur effect */
    border: 1px solid rgba(255, 255, 255, 0.2); /* Light border for definition */
}

/* Titles and Subtitles Styling */
h1, h2, h3, .section-title {
    font-weight: 700; /* Bold text */
    /* Colors appropriate to the background - using a dark gray that stands out on the transparent grey */
    color: #06f7ff; /* Changed from #4a5568 to a more vibrant cyan for section titles */
}

/* Navigation Bar Styling */
.nav-background {
    display: flex;
    justify-content: space-around;
    align-items: center;
    padding: 1rem;
    border-radius: 0.75rem; /* Rounded-xl for nav */
    box-shadow: 0 4px 6px rgba(0,0,0,0.1); /* Shadow-xl for nav */
}

.nav-link {
    padding: 0.5rem 1rem;
    border-radius: 0.5rem; /* Rounded-lg for links */
    font-weight: 600; /* Semibold */
    color: #000000; /* Dark gray for inactive links */
    transition: background-color 0.3s ease-in-out, color 0.3s ease-in-out;
}

.nav-link:hover {
    background-color: #e2e8f0; /* Gray-200 on hover */
    color: #2d3748; /* Darker gray on hover */
}

.nav-link.active {
    color: #000000; /* Indigo-700 for active link */
    background-color: #4b6770; /* Indigo-100 for active link */
    box-shadow: 0 2px 4px rgba(0,0,0,0.1); /* Subtle shadow for active link */
}

/* General inputs and selects */
input[type="file"],
select,
input[type="text"],
input[type="date"] {
    border-radius: 0.5rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

input[type="file"]:focus,
select:focus,
input[type="text"]:focus,
input[type="date"]:focus {
    border-color: #6366f1; /* Indigo-500 */
    box-shadow: 0 0 0 1px #6366f1, 0 0 0 3px rgba(99, 102, 241, 0.2);
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .main-container {
        padding: 1rem;
    }
    h1 {
        font-size: 2rem;
    }
    .nav-background {
        flex-direction: column;
        padding: 0.75rem;
    }
    .nav-background a {
        width: 100%;
        text-align: center;
        margin-bottom: 0.5rem;
    }
    .nav-background a:last-child {
        margin-bottom: 0;
    }
}

/* Custom Alert Message Box */
.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.6);
    z-index: 1000;
    display: none; /* Hidden by default */
    backdrop-filter: blur(3px);
}

.message-box {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: white;
    padding: 25px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    z-index: 1001;
    text-align: center;
    width: 90%;
    max-width: 400px;
    display: none; /* Hidden by default */
    color: #333;
}

.message-box p {
    margin-bottom: 20px;
    font-size: 1.1em;
}

.message-box button {
    background-color: #6366f1;
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
    transition: background-color 0.2s ease;
}

.message-box button:hover {
    background-color: #4f46e5;
}

/* Loading Spinner */
.loading-spinner {
    border: 4px solid #f3f3f3; /* Light grey */
    border-top: 4px solid #6366f1; /* Blue */
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 20px auto; /* Center the spinner */
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Table styling */
#dataHeadTable thead, #statisticsTable thead, #savedGraphsTable thead {
    background-color: #e0e7ff; /* Light indigo */
}

#dataHeadTable th, #statisticsTable th, #savedGraphsTable th {
    padding: 12px 24px;
    text-align: left;
    font-size: 0.75rem;
    font-weight: 600;
    color: #4338ca; /* Darker indigo */
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

#dataHeadTable td, #statisticsTable td, #savedGraphsTable td {
    padding: 10px 24px;
    font-size: 0.875rem;
    color: #374151; /* Dark gray */
}

#dataHeadTable tbody tr:nth-child(even), #statisticsTable tbody tr:nth-child(even), #savedGraphsTable tbody tr:nth-child(even) {
    background-color: #f9fafb; /* Lighter gray for even rows */
}

#dataHeadTable tbody tr:hover, #statisticsTable tbody tr:hover, #savedGraphsTable tbody tr:hover {
    background-color: #eff6ff; /* Lightest blue on hover */
}

#correlationMatrixContainer table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
    font-size: 0.875rem;
}

#correlationMatrixContainer th,
#correlationMatrixContainer td {
    border: 1px solid #ddd;
    padding: 8px;
    text-align: center;
}

#correlationMatrixContainer th {
    background-color: #f2f2f2;
    font-weight: bold;
}

#correlationMatrixContainer td {
    background-color: #fff;
}

/* Color coding for correlation values */
.correlation-positive {
    background-color: #d4edda; /* Light green */
    color: #155724; /* Dark green */
}

.correlation-negative {
    background-color: #f8d7da; /* Light red */
    color: #721c24; /* Dark red */
}

.correlation-neutral {
    background-color: #e2e3e5; /* Light grey */
    color: #383d41; /* Dark grey */
}