:root {
    --bg: #F0F7FE;
    --text: #0b1128;
    --primary: #00bfa6;
    --accent: #ffc107;
    --hover: #009f95;
    --card-bg: #ffffff;
    --border: #d3eff3;
    --card-ring: rgba(0, 0, 0, 0.05);
    --text-muted: #475569;
    --nav-highlight: #F0F7FE;
    --btn-bg: #0071e3;
    --btn-text: #ffffff;
    --btn-border: #0071e3;
    --btn-bg-hover: #005bb5;
    --btn-outline-hover-bg: rgba(0, 113, 227, 0.5);
    --btn-line: #222;
    --link: #0071e3;
    --link-visited: #005bb5;
    /* subtle light layer for readability in light mode */
    /* softer overlay so hero image isn't washed out in light mode */
    --hero-overlay: rgba(251, 251, 251, 0.70);

}

body {
    background-color: var(--bg);
    color: var(--text);
    font-family: sans-serif;
    transition: background 0.3s, color 0.3s;
    margin: 0;
}

a {
    color: var(--link);
}

a:visited {
    color: var(--link-visited);
}

header, nav {
    background-color: var(--card-bg);
    color: var(--text);
}

nav a {
    color: var(--text);
    text-decoration: none;
    margin: 0 1rem;
    transition: color 0.3s;
}

nav a:hover {
    color: var(--primary);
}

.cta-button {
    display: inline-block;
    background-color: var(--btn-bg);
    color: var(--btn-text);
    padding: 12px 24px;
    border: none;
    border-radius: 1000px;
    font-weight: 500;
    text-decoration: none;
    transition: background-color 0.3s;
}

.cta-button:hover {
    background-color: var(--btn-bg-hover);
}

.btn-primary {
    background-color: var(--btn-bg);
    color: var(--btn-text);
    padding: 12px 24px;
    border: none;
    border-radius: 1000px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    box-shadow: 0 0 0 1px var(--card-ring);
    transition: background-color 0.2s ease;
    position: relative;
    overflow: hidden;
}

.btn-primary:hover {
    background-color: var(--btn-bg-hover);
}

.btn-primary .ripple {
    position: absolute;
    border-radius: 50%;
    transform: scale(0);
    animation: ripple 0.4s linear;
    background: rgba(255, 255, 255, 0.4);
    pointer-events: none;
}

@keyframes ripple {
    to {
        transform: scale(2.5);
        opacity: 0;
    }
}

.btn-outline {
    background-color: transparent;
    color: var(--btn-border);
    padding: 12px 24px;
    border: 1px solid var(--btn-border);
    border-radius: 1000px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    transition: background-color 0.2s ease, border-color 0.2s ease;
}

.btn-outline:hover {
    background-color: var(--btn-outline-hover-bg);
}


.theme-dark {
    --bg: #212121;
    --text: #f3f3f3;
    --card-bg: #303030;
    --border: #ffffff26;
    --card-ring: #fff3;
    --accent: #66b5ff;
    --hover: #99ceff;
    --btn-bg: #0071e3;
    --btn-text: #ffffff;
    --btn-border: #0071e3;
    --btn-bg-hover: #005bb5;
    --btn-outline-hover-bg: rgba(0, 113, 227, 0.5);
    --btn-line: #ffffff;
    --link: #66b5ff;
    --link-visited: #99ceff;
    /* darker overlay for dark mode to keep text legible */
    /* match light theme intensity by using a lighter dark overlay */
    --hero-overlay: rgba(0, 0, 0, 0.70);
    --text-muted: #afafaf;
    --nav-highlight: rgba(255, 255, 255, 0.1);
}

footer {
    background-color: var(--card-bg);
    color: var(--text);
    padding: 2rem;
    text-align: center;
    border-top: 1px solid var(--border);
}

/* Accessible focus styles */
a:focus-visible,
button:focus-visible,
input:focus-visible,
label:focus-visible {
    outline: 3px solid var(--btn-bg);
    outline-offset: var(--space-1);
}

/* Respect users who prefer reduced motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation: none !important;
        transition: none !important;
    }
}