:root {
    --color-bg: #f4f5f7;
    --color-surface: #ffffff;
    --color-border: #e2e4e9;
    --color-text: #1f2328;
    --color-text-muted: #6b7280;
    --color-accent: #2563eb;
    --color-accent-hover: #1d4ed8;
    --color-danger: #dc2626;

    --space-1: 4px;
    --space-2: 8px;
    --space-3: 12px;
    --space-4: 16px;
    --space-5: 24px;
    --space-6: 32px;

    --radius: 8px;
    --shadow: 0 1px 2px rgba(16, 24, 40, 0.06), 0 1px 3px rgba(16, 24, 40, 0.08);

    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: var(--space-5);
    font-family: var(--font-sans);
    font-size: 15px;
    line-height: 1.5;
    color: var(--color-text);
    background: var(--color-bg);
}

hr {
    border: none;
    border-top: 1px solid var(--color-border);
    margin: var(--space-5) 0;
}

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

a:hover {
    color: var(--color-accent-hover);
    text-decoration: underline;
}

#header {
    font-size: 22px;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--space-4);
}

#footer {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-3);
    margin-top: var(--space-6);
    color: var(--color-text-muted);
    font-size: 13px;
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-4);
    margin: 0;
}

.footer-copyright {
    margin: 0;
}

.card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

input,
textarea,
select {
    font-family: var(--font-sans);
    font-size: 14px;
    color: var(--color-text);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 6px;
    padding: var(--space-2) var(--space-3);
}

input:focus,
textarea:focus,
select:focus {
    outline: 2px solid var(--color-accent);
    outline-offset: 1px;
}

.row {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-5);
}

.row::after {
    content: "";
    display: table;
    clear: both;
}

.col-3 {
    flex: 1 1 0;
    min-width: 220px;
}

.col-6 {
    flex: 1 1 0;
    min-width: 220px;
}

.right {
    text-align: right;
}

.btn-primary,
.btn-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 6px;
    padding: var(--space-2) var(--space-4);
    font-size: 14px;
    font-family: inherit;
    cursor: pointer;
    border: 1px solid transparent;
}

.btn-primary {
    background: var(--color-accent);
    color: #fff;
}

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

.btn-secondary {
    background: transparent;
    color: var(--color-text);
    border-color: var(--color-border);
}

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

.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(17, 24, 39, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: var(--space-4);
}

.modal {
    background: var(--color-surface);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: var(--space-5);
    max-width: 360px;
    width: 100%;
}

.modal p {
    margin: 0 0 var(--space-4);
}

.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: var(--space-3);
}

:root {
    color-scheme: light;
}

:root[data-theme="dark"] {
    color-scheme: dark;
    --color-bg: #16181d;
    --color-surface: #1f2228;
    --color-border: #2f333b;
    --color-text: #e6e8eb;
    --color-text-muted: #9aa1ac;
    --color-accent: #3b82f6;
    --color-accent-hover: #60a5fa;
    --color-danger: #f87171;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.4), 0 4px 12px rgba(0, 0, 0, 0.3);
}

.theme-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 26px;
    height: 26px;
    padding: 0;
    border: none;
    border-radius: 6px;
    background: none;
    color: var(--color-text-muted);
    cursor: pointer;
}

.theme-toggle:hover {
    background: var(--color-border);
    color: var(--color-text);
}

.theme-toggle .icon-moon,
.theme-toggle .icon-sun {
    display: block;
}

.theme-toggle .icon-sun {
    display: none;
}

:root[data-theme="dark"] .theme-toggle .icon-moon {
    display: none;
}

:root[data-theme="dark"] .theme-toggle .icon-sun {
    display: block;
}

@media only screen and (max-width: 768px) {
    body {
        padding: var(--space-3);
        font-size: 16px;
    }

    #header {
        font-size: 24px;
    }

    .row {
        flex-direction: column;
        gap: var(--space-4);
    }
}