/* Global */

* {
    box-sizing: border-box;
}

html {
    font-size: 16px;
}

body,
main,
footer,
#theme-toggle {
    transition:
        background-color 0.5s ease,
        color 0.5s ease,
        border-color 0.5s ease;
}

:root {
    --background: #E8E2D5;
    --surface: #F4F7F6;
    --text: #26383A;
    --border: #B8C8C5;
    --link: #3F7C82;
    --hover: #D5E7E2;
}

@media (prefers-color-scheme: dark) {
    :root {
        --background: #17282B;
        --surface: #233A3D;
        --text: #E5EEEC;
        --border: #40595B;
        --link: #6FA9A5;
        --hover: #304C4F;
    }
}

[data-theme="light"] {
    --background: #E8E2D5;
    --surface: #F4F7F6;
    --text: #26383A;
    --border: #B8C8C5;
    --link: #3F7C82;
    --hover: #D5E7E2;
}

[data-theme="dark"] {
    --background: #17282B;
    --surface: #233A3D;
    --text: #E5EEEC;
    --border: #40595B;
    --link: #6FA9A5;
    --hover: #304C4F;
}

body {
    margin: 0;
    color: var(--text);
    background-color: var(--background);
    font-size: 16px;
    font-family: Arial, sans-serif;
    line-height: 1.7;
}

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

main {
    width: 100%;
    max-width: 1000px;
    margin: 20px auto 0;
    padding: 50px 40px;
    background-color: var(--surface);
    border: 1px solid var(--border);
}

/* Main content */

main section {
    margin-bottom: 40px;
    padding-bottom: 30px;
    border-bottom: 1px solid var(--border);
}

main section:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

main h2 {
    margin-top: 0;
    margin-bottom: 15px;
}

main p {
    margin: 0 0 20px;
}

/* Header */

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px 40px;
    border-bottom: 1px solid var(--border);
}

header h1 {
    margin: 0;
}

nav {
    display: flex;
    gap: 20px;
}

.header-controls {
    display: flex;
    align-items: center;
    gap: 20px;
}

/* Navigation links */

nav a {
    padding: 8px 0;
}

nav a:hover {
    text-decoration: underline;
}

/* Project links */

main a {
    display: inline-block;
    padding: 8px 16px;
    border: 1px solid var(--border);
    border-radius: 6px;
}

main a:hover {
    background-color: var(--hover);
}

#theme-toggle {
    padding: 8px 16px;
    border: 1px solid var(--border);
    border-radius: 6px;
    color: var(--link);
    background-color: var(--surface);
    cursor: pointer;
}

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

/* Footer */

footer {
    max-width: 1000px;
    margin: 40px auto 0;
    padding: 40px;
    background-color: var(--surface);
    border-top: 1px solid var(--border);
}

footer h2 {
    margin-top: 0;
    margin-bottom: 20px;
}

footer p {
    margin: 0 0 15px;
}

footer p:last-child {
    margin-bottom: 0;
}

footer a {
    text-decoration: underline;
}

/* Typography */

h1,
h2 {
    line-height: 1.2;
}

h1 {
    font-size: 2rem;
    margin-bottom: 15px;
}

h2 {
    font-size: 1.5rem;
    margin-bottom: 15px;
}  

/* Mobile */

@media (max-width: 600px) {
    header {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }

    nav {
        gap: 15px;
        flex-wrap: wrap;
    }

    main {
        padding: 40px 20px;
    }

    footer {
        padding: 40px 20px;
    }
}