:root {
    --primary: #1976D2;
    --primary-dark: #0D47A1;
    --primary-light: #E3F2FD;
    --accent: #2E7D32;
    --danger: #D32F2F;
    --danger-light: #FFEBEE;
    --warning: #F57F17;
    --warning-light: #FFF8E1;
    --surface: #FFFFFF;
    --background: #F8F9FA;
    --text-primary: #1A1A1A;
    --text-secondary: #5F6368;
    --border: #E0E0E0;
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-family);
    background-color: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Header & Navbar */
.site-header {
    background-color: var(--surface);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    max-width: 960px;
    margin: 0 auto;
    padding: 16px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
}

.brand {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary-dark);
    text-decoration: none;
    letter-spacing: -0.5px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.brand span {
    color: var(--primary);
    font-weight: 400;
    font-size: 14px;
    background: var(--primary-light);
    padding: 2px 8px;
    border-radius: 4px;
}

.nav-links {
    display: flex;
    gap: 20px;
    list-style: none;
    align-items: center;
    flex-wrap: wrap;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    transition: color 0.15s ease;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--primary);
}

/* Layout Container */
.main-content {
    flex: 1;
    max-width: 960px;
    width: 100%;
    margin: 32px auto;
    padding: 0 20px;
}

.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 40px;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.03);
}

/* Typography */
h1 {
    font-size: 28px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 12px;
    letter-spacing: -0.5px;
}

.page-subtitle {
    font-size: 15px;
    color: var(--text-secondary);
    margin-bottom: 24px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border);
}

h2 {
    font-size: 20px;
    font-weight: 600;
    color: var(--primary-dark);
    margin-top: 32px;
    margin-bottom: 12px;
    border-left: 4px solid var(--primary);
    padding-left: 12px;
}

h3 {
    font-size: 16px;
    font-weight: 600;
    margin-top: 18px;
    margin-bottom: 8px;
    color: var(--text-primary);
}

p {
    margin-bottom: 14px;
    color: #333333;
}

ul, ol {
    margin-left: 24px;
    margin-bottom: 18px;
}

li {
    margin-bottom: 8px;
    color: #333333;
}

/* Callout Banners */
.alert-box {
    border-radius: 8px;
    padding: 16px 20px;
    margin: 20px 0;
    font-size: 14px;
    line-height: 1.5;
}

.alert-info {
    background-color: var(--primary-light);
    border: 1px solid #BBDEFB;
    color: #0D47A1;
}

.alert-danger {
    background-color: var(--danger-light);
    border: 1px solid #FFCDD2;
    color: var(--danger);
}

.alert-warning {
    background-color: var(--warning-light);
    border: 1px solid #FFE082;
    color: #5D4037;
}

/* Step list */
.step-container {
    background: #FDFDFD;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 24px;
    margin: 20px 0;
}

.step-container ol {
    margin-left: 20px;
    margin-bottom: 0;
}

/* Grid for home */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-top: 24px;
}

.feature-item {
    background: #FAFAFA;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 20px;
}

.feature-item h3 {
    margin-top: 0;
    color: var(--primary);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 10px 20px;
    border-radius: 6px;
    font-size: 15px;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: background 0.15s ease;
}

.btn-primary {
    background: var(--primary);
    color: #FFF;
    border: 1px solid var(--primary);
}

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

.btn-outline {
    background: transparent;
    color: var(--primary);
    border: 1px solid var(--primary);
}

.btn-outline:hover {
    background: var(--primary-light);
}

/* Footer */
.site-footer {
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding: 32px 20px;
    margin-top: auto;
}

.footer-container {
    max-width: 960px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
    font-size: 14px;
    color: var(--text-secondary);
}

.footer-meta p {
    margin-bottom: 4px;
    font-size: 13px;
    color: var(--text-secondary);
}

.footer-links {
    display: flex;
    gap: 16px;
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
}

.footer-links a:hover {
    color: var(--primary);
    text-decoration: underline;
}

/* Responsive */
@media (max-width: 640px) {
    .card {
        padding: 24px 18px;
    }
    .nav-container {
        flex-direction: column;
        align-items: flex-start;
    }
    .nav-links {
        gap: 12px;
        width: 100%;
        justify-content: space-between;
    }
    .footer-container {
        flex-direction: column;
        align-items: flex-start;
    }
}