:root {
    --primary-color: #6A5ACD;
    --secondary-color: #20B2AA;
    --sidebar-bg: #2c3e50;
    --text-color-dark: #34495e;
    --text-color-light: #ecf0f1;
    --hover-color: #7B68EE;
}

body {
    font-family: 'Poppins', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    padding: 0;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.app-layout {
    display: flex;
    height: 100vh;
    overflow: hidden;
}

.sidebar {
    width: 260px;
    background-color: var(--sidebar-bg);
    height: 100%;
    position: fixed;
    top: 0;
    left: 0;
    padding: 1.5rem;
    transition: width 0.3s ease, transform 0.3s ease;
    z-index: 10;
    box-shadow: 2px 0 10px rgba(0,0,0,0.1);
}

.sidebar.collapsed {
    width: 80px;
}

.sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.sidebar-header h2 {
    margin: 0;
    font-weight: 700;
    font-size: 1.8rem;
    color: var(--text-color-light);
    transition: opacity 0.3s ease;
}

.sidebar.collapsed .sidebar-header h2 {
    opacity: 0;
}

/* Unified sidebar toggle button */
#sidebar-toggle {
    background: transparent;
    border: none;
    color: var(--text-color-light);
    font-size: 1.2rem;
    cursor: pointer;
    transition: transform 0.3s ease;
    position: fixed; /* Fixed position for both desktop and mobile */
    top: 1rem;
    left: 1rem;
    z-index: 1001; /* Ensure it's above other content */
    background-color: var(--primary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 2px 10px rgba(0,0,0,0.2);
}

#sidebar-toggle:hover {
    color: var(--hover-color);
}

/* Desktop specific toggle behavior */
@media (min-width: 769px) {
    #sidebar-toggle {
        position: absolute; /* Position relative to sidebar on desktop */
        top: 1.5rem;
        right: 1.5rem;
        left: auto; /* Reset left position */
        background: transparent; /* Reset background */
        box-shadow: none; /* Reset shadow */
    }

    .sidebar.collapsed #sidebar-toggle {
        transform: rotate(180deg);
    }
}

.sidebar-nav {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.sidebar-nav .nav-link {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.8rem 1rem;
    border-radius: 8px;
    color: var(--text-color-light);
    font-weight: 500;
    text-decoration: none;
    transition: background-color 0.2s, transform 0.2s;
}

.sidebar-nav .nav-link:hover {
    background-color: rgba(255, 255, 255, 0.1);
    transform: translateX(5px);
}

.sidebar-nav .nav-link.active {
    background-color: var(--primary-color);
    font-weight: 700;
    box-shadow: 0 4px 15px rgba(106, 90, 205, 0.3);
}

.sidebar-nav .nav-link .nav-text {
    opacity: 1;
    transition: opacity 0.3s ease;
}

.sidebar.collapsed .nav-link .nav-text {
    opacity: 0;
    width: 0;
    overflow: hidden;
}

.sidebar.collapsed .nav-link {
    justify-content: center;
}

.main-content {
    margin-left: 260px;
    width: calc(100% - 260px);
    height: 100%;
    transition: margin-left 0.3s ease, width 0.3s ease;
    background-image: url('BGround.png');
    background-size: cover;
    background-position: center;
    position: relative;
    overflow-y: auto;
}

.main-content.collapsed {
    margin-left: 80px;
    width: calc(100% - 80px);
}

.container {
    width: 100%;
    min-height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2.5rem;
    box-sizing: border-box;
}

.page {
    display: none;
    width: 100%;
    max-width: 900px;
}

.page.active {
    display: block;
    animation: fadeIn 0.5s;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.card {
    background: rgba(0, 0, 0, 0.3);
    border-radius: 16px;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    padding: 2.5rem;
    color: var(--text-color-light);
    margin-bottom: 2rem;
}

.card h2 {
    color: var(--text-color-light);
    font-weight: 700;
    margin-bottom: 1.5rem;
    text-align: center;
}

.card p, .card label {
    color: var(--text-color-light);
    font-weight: 500;
    margin-bottom: 0.5rem;
    display: block;
}

.file-upload-wrapper {
    position: relative;
    display: inline-block;
    width: 100%;
    margin-bottom: 1rem;
}

#csv-upload {
    display: none;
}

.file-upload-wrapper label {
    display: block;
    padding: 1rem;
    background: rgba(255, 255, 255, 0.2);
    border: 2px dashed rgba(255, 255, 255, 0.5);
    border-radius: 8px;
    text-align: center;
    cursor: pointer;
    transition: background-color 0.2s, border-color 0.2s;
}

.file-upload-wrapper label:hover {
    background: rgba(255, 255, 255, 0.3);
    border-color: var(--primary-color);
}

select, input[type="text"], button {
    width: 100%;
    padding: 1rem;
    margin-bottom: 1rem;
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: var(--text-color-light);
    font-size: 1rem;
    box-sizing: border-box;
}

select option {
    background: #fff;
    color: var(--text-color-dark);
}

select:focus, input:focus {
    background: rgba(255, 255, 255, 0.2);
    box-shadow: 0 0 0 3px rgba(106, 90, 205, 0.3);
    outline: none;
}

button {
    background-color: var(--primary-color);
    cursor: pointer;
    transition: background-color 0.2s, transform 0.2s;
}

button:hover {
    background-color: var(--hover-color);
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(106, 90, 205, 0.4);
}

#plot-output {
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    padding: 1rem;
    margin-top: 1rem;
    min-height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
}

#plot-img {
    max-width: 100%;
    max-height: 100%;
    border-radius: 8px;
}

#train-output, #ai-answer, #upload-status, #plot-error {
    background-color: rgba(0, 0, 0, 0.2);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: var(--text-color-light);
    padding: 1rem;
    border-radius: 8px;
    margin-top: 1rem;
    min-height: 50px;
    white-space: pre-wrap;
    word-wrap: break-word;
    cursor: pointer;
}

.loader {
    border: 4px solid #f3f3f3;
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    display: none;
}

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

.nav-text {
    animation: fadeInText 0.5s forwards;
}

@keyframes fadeInText {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

.sidebar.collapsed .nav-text {
    animation: none;
}

/* Overlay for when sidebar is active */
.overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 999; /* Below sidebar, above content */
}

.overlay.active {
    display: block;
}

/* Responsive adjustments for smaller screens */
@media (max-width: 768px) {
    /* Hide desktop toggle on mobile */
    #desktop-sidebar-toggle {
        display: none;
    }

    /* Show mobile toggle */
    #sidebar-toggle {
        display: flex; 
    }

    .app-layout {
        flex-direction: column;
        height: auto; /* Allow content to dictate height */
        min-height: 100vh; /* Ensure it takes at least full viewport height */
    }

    .sidebar {
        width: 250px; /* Slightly narrower sidebar for mobile */
        height: 100vh; /* Full viewport height */
        position: fixed; /* Keep it fixed for overlay effect */
        top: 0;
        left: 0;
        padding: 1.5rem;
        transform: translateX(-100%); /* Hide sidebar by default */
        transition: transform 0.3s ease;
        z-index: 1000; /* Ensure it's on top of everything */
        box-shadow: 2px 0 10px rgba(0,0,0,0.1);
        overflow-y: auto; /* Allow sidebar content to scroll if needed */
    }

    .sidebar.active {
        transform: translateX(0); /* Slide in when active */
    }

    .sidebar.collapsed {
        /* On mobile, 'collapsed' means hidden, so it's the same as default hidden state */
        width: 250px;
        transform: translateX(-100%);
    }

    .sidebar-header {
        margin-bottom: 2rem;
    }

    .sidebar-header h2 {
        opacity: 1; /* Always show title on mobile */
    }

    .sidebar-nav .nav-link .nav-text {
        opacity: 1; /* Always show text on mobile */
        width: auto;
        overflow: visible;
    }

    .sidebar-nav .nav-link {
        justify-content: flex-start;
    }

    .main-content {
        margin-left: 0; /* Remove left margin */
        width: 100%; /* Take full width */
        min-height: 100vh; /* Ensure main content takes at least full viewport height */
        padding: 1rem; /* Adjust padding */
        overflow-y: auto; /* Ensure scrolling */
        background-size: cover; /* Ensure background covers well */
        background-position: center;
    }

    .main-content.collapsed {
        margin-left: 0;
        width: 100%;
    }

    .container {
        padding: 1rem; /* Adjust container padding */
        /* Center the card horizontally */
        justify-content: center;
        align-items: flex-start; /* Align items to start to prevent vertical centering issues */
    }

    .page {
        max-width: 100%; /* Allow pages to take full width */
    }

    .card {
        padding: 1.5rem; /* Adjust card padding */
        width: 95%; /* Give it a max width to prevent stretching */
        box-sizing: border-box; /* Include padding in width */
    }

    /* Adjust font sizes for better mobile readability */
    body {
        font-size: 0.9rem;
    }

    .card h2 {
        font-size: 1.5rem;
    }

    select, input[type="text"], button {
        padding: 0.8rem;
        font-size: 0.9rem;
    }
}