:root {
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
    
    /* Light Theme */
    --bg-color-light: #f5f5f7;
    --text-color-light: #1d1d1f;
    --card-bg-color-light: #ffffff;
    --link-color-light: #0071e3;
    --border-color-light: #d2d2d7;
    --shadow-color-light: rgba(0, 0, 0, 0.1);

    /* Dark Theme */
    --bg-color-dark: #121212;
    --text-color-dark: #f5f5f7;
    --card-bg-color-dark: #1e1e1e;
    --link-color-dark: #0a84ff;
    --border-color-dark: #3a3a3c;
    --shadow-color-dark: rgba(0, 0, 0, 0.2);
}

html {
    font-size: 16px;
}

body {
    font-family: var(--font-family);
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
}

:root[data-theme="light"] {
    --bg-color: var(--bg-color-light);
    --text-color: var(--text-color-light);
    --card-bg-color: var(--card-bg-color-light);
    --link-color: var(--link-color-light);
    --border-color: var(--border-color-light);
    --shadow-color: var(--shadow-color-light);
}

:root[data-theme="dark"] {
    --bg-color: var(--bg-color-dark);
    --text-color: var(--text-color-dark);
    --card-bg-color: var(--card-bg-color-dark);
    --link-color: var(--link-color-dark);
    --border-color: var(--border-color-dark);
    --shadow-color: var(--shadow-color-dark);
}

header {
    text-align: center;
    padding-bottom: 3rem;
    margin-bottom: 3rem;
    border-bottom: 1px solid var(--border-color);
}

header h1 {
    font-size: 3rem;
    font-weight: 700;
}

.app-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    grid-gap: 2rem;
}

.app-card {
    background-color: var(--card-bg-color);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 12px var(--shadow-color);
    transition: background-color 0.3s ease, box-shadow 0.3s ease, transform 0.2s ease;
}

.app-card:hover {
    transform: translateY(-5px);
}

.full-width {
    grid-column: span 2;
}

.app-card h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.app-card p {
    line-height: 1.6;
}

a {
    color: var(--link-color);
    text-decoration: none;
    font-weight: 500;
}

a:hover {
    text-decoration: underline;
}

footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    font-size: 0.9rem;
    color: var(--text-color);
}

.theme-switch-wrapper {
    display: flex;
    align-items: center;
}

.theme-switch {
    display: inline-block;
    height: 24px;
    position: relative;
    width: 48px;
}

.theme-switch input {
    display:none;
}

.slider {
    background-color: #ccc;
    bottom: 0;
    cursor: pointer;
    left: 0;
    position: absolute;
    right: 0;
    top: 0;
    transition: .4s;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 4px;
}

.slider:before {
    background-color: #fff;
    bottom: 2px;
    content: "";
    height: 20px;
    left: 2px;
    position: absolute;
    transition: .4s;
    width: 20px;
}

:root[data-theme="dark"] .slider {
    background-color: #3a3a3c;
}


input:checked + .slider {
    background-color: var(--link-color);
}

:root[data-theme="dark"] input:checked + .slider {
    background-color: #0a84ff;
}


input:checked + .slider:before {
    transform: translateX(24px);
}

.slider.round {
    border-radius: 24px;
}

.slider.round:before {
    border-radius: 50%;
}

.sun-icon, .moon-icon {
    color: #fff;
    transition: color 0.3s ease;
}

input:checked + .slider .sun-icon {
    color: #fff;
}

input:not(:checked) + .slider .moon-icon {
    color: #fff;
}