:root {
    /* Light Theme (Default) */
    --bg-gradient: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    --card-bg: rgba(255, 255, 255, 0.7);
    --card-border: rgba(0, 0, 0, 0.08);
    --primary: #0284c7;
    --text-main: #0f172a;
    --text-muted: #475569;
    --nav-bg: rgba(248, 250, 252, 0.8);
    --nav-hover: rgba(0, 0, 0, 0.05);
    --nav-active: #0ea5e9;
    --nav-active-text: #ffffff;
    --chart-bg: #ffffff;
}

[data-theme="dark"] {
    /* Dark Theme */
    --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e1b4b 100%);
    --card-bg: rgba(30, 41, 59, 0.7);
    --card-border: rgba(255, 255, 255, 0.08);
    --primary: #00f2fe;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --nav-bg: rgba(15, 23, 42, 0.8);
    --nav-hover: rgba(255, 255, 255, 0.1);
    --nav-active: #38bdf8;
    --nav-active-text: #0f172a;
    --chart-bg: #f8fafc; /* keep charts light for readability */
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Outfit', sans-serif;
    background: var(--bg-gradient);
    color: var(--text-main);
    margin: 0;
    padding: 0;
    min-height: 100vh;
    transition: background 0.3s, color 0.3s;
}

/* Glassmorphism background decorations */
body::before {
    content: '';
    position: fixed;
    top: -20%;
    left: -10%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(0, 242, 254, 0.1) 0%, rgba(0,0,0,0) 70%);
    z-index: -1;
    pointer-events: none;
}

body::after {
    content: '';
    position: fixed;
    bottom: -10%;
    right: -10%;
    width: 700px;
    height: 700px;
    background: radial-gradient(circle, rgba(139, 92, 246, 0.08) 0%, rgba(0,0,0,0) 70%);
    z-index: -1;
    pointer-events: none;
}

/* Top Navigation */
.topnav {
    background: var(--nav-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--card-border);
    overflow: hidden;
    position: sticky;
    top: 0;
    z-index: 100;
}

.topnav a {
    float: left;
    display: block;
    color: var(--text-main);
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
    font-size: 16px;
    font-weight: 500;
    transition: all 0.2s ease;
}

.topnav a:hover {
    background-color: var(--nav-hover);
}

.topnav a.active {
    background-color: var(--nav-active);
    color: var(--nav-active-text);
    font-weight: 600;
}

.topnav .icon {
    display: none;
}

/* Theme Toggle Button */
.theme-toggle-btn {
    float: right;
    padding: 14px 16px;
    background: transparent;
    border: none;
    color: var(--text-main);
    font-size: 16px;
    cursor: pointer;
    transition: color 0.2s;
    display: flex;
    align-items: center;
    gap: 8px;
}
.theme-toggle-btn:hover {
    color: var(--primary);
}

@media screen and (max-width: 768px) {
    .topnav a:not(:first-child):not(.theme-toggle-btn) {
        display: none;
    }
    .topnav a.icon {
        float: right;
        display: block;
    }
    .topnav.responsive {
        position: relative;
    }
    .topnav.responsive a.icon {
        position: absolute;
        right: 0;
        top: 0;
    }
    .topnav.responsive a {
        float: none;
        display: block;
        text-align: left;
    }
    .theme-toggle-btn {
        float: none;
        width: 100%;
        text-align: left;
        justify-content: flex-start;
    }
}

/* Sidebar links */
.sidebar {
    margin: 0;
    padding: 1rem 0;
    width: 220px;
    background: var(--nav-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-right: 1px solid var(--card-border);
    position: absolute;
    height: calc(100% - 50px);
    overflow: auto;
    font-size: 0.95rem;
    z-index: 90;
}

.sidebar a {
    display: block;
    color: var(--text-main);
    padding: 12px 16px;
    text-decoration: none;
    font-weight: 400;
    transition: background 0.2s;
}

.sidebar a:hover:not(.active) {
    background-color: var(--nav-hover);
}

/* Page content */
div.content {
    margin-left: 220px;
    padding: 20px;
}

@media screen and (max-width: 700px) {
    .sidebar {
        width: 100%;
        height: auto;
        position: relative;
        border-right: none;
        border-bottom: 1px solid var(--card-border);
    }
    .sidebar a {
        float: left;
        padding: 10px;
    }
    div.content {
        margin-left: 0;
    }
}

@media screen and (max-width: 400px) {
    .sidebar a {
        text-align: center;
        float: none;
    }
}

/* Vega Embed container styling */
#vis.vega-embed,
.vega-embed {
    background: var(--chart-bg);
    border-radius: 12px;
    padding: 20px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    margin: 20px auto 20px 240px; /* Leave space for the 220px sidebar */
    border: 1px solid var(--card-border);
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    max-width: calc(100% - 260px);
    overflow-x: auto;
    color: #0f172a !important; /* Force dark text since background is always light */
}

/* Modern Checkbox / Toggle for Vega Bindings */
.vega-bindings {
    margin-top: 15px;
    width: 100%;
    display: flex;
    justify-content: center;
}

.vega-bindings label {
    display: flex;
    align-items: center;
    cursor: pointer;
    font-weight: 500;
    font-size: 0.95rem;
    color: #0f172a !important;
}

/* Hide default checkbox */
.vega-bindings input[type="checkbox"] {
    appearance: none;
    -webkit-appearance: none;
    width: 44px;
    height: 24px;
    background: #cbd5e1;
    border-radius: 20px;
    position: relative;
    cursor: pointer;
    outline: none;
    margin-right: 10px;
    transition: background 0.3s;
}

/* Toggle circle */
.vega-bindings input[type="checkbox"]::after {
    content: '';
    position: absolute;
    top: 2px;
    left: 2px;
    width: 20px;
    height: 20px;
    background: white;
    border-radius: 50%;
    transition: transform 0.3s cubic-bezier(0.4, 0.0, 0.2, 1);
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

/* Checked state */
.vega-bindings input[type="checkbox"]:checked {
    background: #0ea5e9;
}

.vega-bindings input[type="checkbox"]:checked::after {
    transform: translateX(20px);
}

@media screen and (max-width: 700px) {
    #vis.vega-embed,
    .vega-embed {
        margin: 20px auto;
        max-width: 95%;
    }
}

[data-theme="dark"] #vis.vega-embed,
[data-theme="dark"] .vega-embed {
    /* Keep charts light for readability but soften the border/shadow */
    border: 1px solid rgba(255,255,255,0.1);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
}

/* Titles and Headers */
h1, h2, h3, h4, h5, h6 {
    color: var(--text-main);
    font-weight: 600;
}

h4 {
    color: var(--text-muted);
}

/* Footer styling */
footer {
    padding: 2rem;
    margin-top: 3rem;
    border-top: 1px solid var(--card-border);
    background: var(--nav-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
}

footer p {
    color: var(--text-muted);
}
footer a {
    color: var(--primary);
    text-decoration: none;
}
footer a:hover {
    text-decoration: underline;
}