:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --text-dark: #1e293b;
    --text-gray: #64748b;
    --border-color: #e2e8f0;
    --background-light: #fafafa;
}

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

body {
    font-family: system-ui, -apple-system, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background: var(--background-light);
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

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

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.nav-link {
    color: var(--text-gray);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.875rem;
    transition: color 0.2s;
}

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

.nav-link.btn-cta {
    background: var(--primary-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 0.375rem;
    font-weight: 600;
    transition: background-color 0.2s;
}

.nav-link.btn-cta:hover {
    background: var(--primary-dark);
    color: white;
}

.logo {
    font-weight: 600;
    color: var(--primary-color);
    text-decoration: none;
    font-size: 1.25rem;
}

.btn-login {
    color: var(--text-gray);
    text-decoration: none;
    font-weight: 400;
    font-size: 0.75rem;
    transition: color 0.2s;
}

.btn-login:hover {
    color: var(--primary-color);
    text-decoration: underline;
}

/* Content Section */
.content-section {
    padding: 4rem 0;
    min-height: calc(100vh - 200px);
}

.content-wrapper {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    max-width: 900px;
    margin: 0 auto;
}

.content-box {
    background: white;
    padding: 3rem;
    border-radius: 16px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
    border: 2px solid var(--primary-color);
    width: 100%;
}

.content-box h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-dark);
    text-align: center;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 1rem;
}

.last-updated {
    text-align: center;
    color: var(--text-gray);
    font-size: 0.9rem;
    margin-bottom: 2rem;
    font-style: italic;
}

/* Email Obfuscation */
.email-obfuscate em {
    display: none;
}

/* Table of Contents */
.toc-box {
    background-color: #f8f9fa;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1rem 1.5rem;
    margin-bottom: 2.5rem;
}

.toc-title {
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--text-dark);
    margin-bottom: 0.75rem;
}

.toc-box ul {
    list-style: none;
    padding-left: 0;
    margin: 0;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.5rem 1.5rem;
}

.toc-box ul li a {
    color: var(--primary-color);
    text-decoration: none;
    font-size: 0.9rem;
    transition: text-decoration 0.2s;
}

.toc-box ul li a:hover {
    text-decoration: underline;
}

.content-text {
    margin-bottom: 3rem;
}

.content-text h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-top: 2rem;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border-color);
}

.content-text h2:first-of-type {
    margin-top: 0;
}

.content-text h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-top: 1.5rem;
    margin-bottom: 0.75rem;
}

.content-text p {
    font-size: 1rem;
    color: var(--text-dark);
    margin-bottom: 1.5rem;
    line-height: 1.7;
    text-align: left;
}

.content-text p:last-child {
    margin-bottom: 0;
}

.content-text strong {
    font-weight: 600;
    color: var(--text-dark);
}

.content-text ul {
    margin: 1rem 0 1.5rem 1.5rem;
    padding-left: 0;
}

.content-text ul li {
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

.content-text a {
    color: var(--primary-color);
    text-decoration: underline;
}

.content-text a:hover {
    color: var(--primary-dark);
}

.action-section {
    display: flex;
    gap: 1rem;
    justify-content: center;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    flex-wrap: wrap;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    padding: 0.875rem 1.5rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    transition: all 0.2s;
    display: inline-block;
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
}

.btn-secondary {
    background: white;
    color: var(--primary-color);
    padding: 0.875rem 1.5rem;
    border: 2px solid var(--primary-color);
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    transition: all 0.2s;
    display: inline-block;
}

.btn-secondary:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-1px);
}

/* Footer */
.footer {
    background: var(--text-dark);
    color: white;
    padding: 3rem 0 1.5rem;
    text-align: center;
    margin-top: auto;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-links a {
    color: #94a3b8;
    text-decoration: none;
    transition: color 0.2s;
}

.footer-links a:hover {
    color: white;
}

.copyright {
    color: #94a3b8;
    font-size: 0.875rem;
}

/* Tablet Responsive */
@media (max-width: 1024px) {
    .container {
        padding: 0 2rem;
    }

    .content-box {
        padding: 2.5rem;
    }

    .content-box h1 {
        font-size: 2rem;
    }

    .content-text h2 {
        font-size: 1.375rem;
    }

    .content-text h3 {
        font-size: 1.125rem;
    }
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .container {
        padding: 0 1rem;
    }

    .logo {
        font-size: 0.875rem;
    }

    .nav-links {
        gap: 1rem;
    }

    .nav-link {
        font-size: 0.75rem;
    }

    .nav-link.btn-cta {
        padding: 0.4rem 0.8rem;
        font-size: 0.75rem;
    }

    .btn-login {
        font-size: 0.7rem;
    }

    .content-section {
        padding: 2rem 0;
        min-height: calc(100vh - 150px);
    }

    .content-box {
        padding: 1.5rem;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    }

    .content-box h1 {
        font-size: 1.75rem;
        margin-bottom: 1.5rem;
    }

    .content-text h2 {
        font-size: 1.25rem;
        margin-top: 1.5rem;
        margin-bottom: 0.875rem;
    }

    .content-text h3 {
        font-size: 1.125rem;
        margin-top: 1.25rem;
        margin-bottom: 0.625rem;
    }

    .content-text p {
        font-size: 0.9375rem;
        margin-bottom: 1.25rem;
    }

    .content-text ul {
        margin: 0.75rem 0 1.25rem 1.25rem;
    }

    .action-section {
        flex-direction: column;
        align-items: center;
        margin-top: 1.5rem;
        padding-top: 1.5rem;
    }

    .btn-primary,
    .btn-secondary {
        width: 100%;
        max-width: 280px;
        text-align: center;
    }

    .footer {
        padding: 2rem 0 1rem;
    }

    .footer-links {
        flex-wrap: wrap;
        gap: 0.75rem 1.5rem;
        margin-bottom: 1.5rem;
    }

    .copyright {
        font-size: 0.75rem;
        padding: 0 1rem;
    }

    .toc-box ul {
        grid-template-columns: 1fr;
    }

    .toc-box {
        padding: 1rem;
        margin-bottom: 2rem;
    }
}

/* Small Mobile */
@media (max-width: 480px) {
    .content-box h1 {
        font-size: 1.5rem;
    }

    .content-text h2 {
        font-size: 1.125rem;
    }

    .content-text h3 {
        font-size: 1rem;
    }

    .content-text p {
        font-size: 0.875rem;
    }

    .content-box {
        padding: 1.25rem;
    }
}