/* Black and White Theme */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #000;
    background-color: #fff;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 20px;
    width: 100%;
}

/* Header */
header {
    background-color: #000;
    color: #fff;
    padding: 2rem 0;
    text-align: center;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
    font-weight: 300;
}

/* Navigation */
nav {
    background-color: #fff;
    border-bottom: 2px solid #000;
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
}

nav a {
    color: #000;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    padding: 0.5rem 1rem;
    border: 2px solid transparent;
    transition: all 0.3s ease;
    display: inline-block;
}

nav a:hover {
    border-bottom: 2px solid #000;
    background-color: #f5f5f5;
}

/* Main Content */
main {
    flex: 1;
    padding: 2rem 0;
}

.troubleshooting-section {
    margin-bottom: 4rem;
}

.troubleshooting-section:first-of-type {
    margin-top: 1.5rem;
}

.troubleshooting-section h2 {
    font-size: 2rem;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 3px solid #000;
    text-align: center;
}

/* Troubleshooting Cards */
.troubleshooting-card {
    background-color: #fff;
    border: 2px solid #000;
    margin-bottom: 1.5rem;
    border-radius: 8px;
    overflow: hidden;
    transition: box-shadow 0.3s ease;
}

.troubleshooting-card:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.card-header {
    background-color: #000;
    color: #fff;
    padding: 1.25rem 1.5rem;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1.2rem;
    font-weight: 600;
    user-select: none;
    transition: background-color 0.3s ease;
}

.card-header:hover {
    background-color: #333;
}

.toggle-icon {
    font-size: 1.5rem;
    font-weight: 300;
    transition: transform 0.3s ease;
    line-height: 1;
}

.card-header.active .toggle-icon {
    transform: rotate(45deg);
}

.card-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.4s ease;
    padding: 0 1.5rem;
}

.card-content.active {
    max-height: 2000px;
    padding: 1.5rem;
}

.card-content ol {
    padding-left: 1.5rem;
    margin-top: 0.5rem;
}

.card-content li {
    margin-bottom: 0.75rem;
    line-height: 1.7;
}

.card-content li strong {
    color: #000;
    font-weight: 600;
}

/* Contact Section */
.contact-section {
    margin-top: 4rem;
    margin-bottom: 2rem;
}

.contact-box {
    background-color: #000;
    color: #fff;
    padding: 2.5rem;
    border-radius: 8px;
    text-align: center;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.contact-box h2 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
    font-weight: 700;
    border-bottom: none;
    padding-bottom: 0;
}

.contact-box p {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 1rem;
    opacity: 0.95;
}

.contact-box a {
    color: #fff;
    text-decoration: underline;
    text-decoration-color: rgba(255, 255, 255, 0.6);
    transition: text-decoration-color 0.3s ease;
    outline: none;
}

.contact-box a:hover {
    text-decoration-color: #fff;
    opacity: 1;
}

.contact-box a:visited {
    color: #fff;
}

.contact-box a:focus {
    outline: none;
    color: #fff;
}

.contact-box a:active {
    outline: none;
    color: #fff;
}

.contact-instruction {
    font-weight: 600;
    font-size: 1.15rem;
    margin-top: 1.5rem;
    margin-bottom: 0;
}

/* Footer */
footer {
    background-color: #000;
    color: #fff;
    padding: 2rem 0;
    text-align: center;
    margin-top: 3rem;
}

footer p {
    opacity: 0.8;
    font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    nav ul {
        gap: 1rem;
    }
    
    nav a {
        font-size: 1rem;
        padding: 0.4rem 0.8rem;
    }
    
    .troubleshooting-section h2 {
        font-size: 1.75rem;
    }
    
    .card-header {
        font-size: 1.1rem;
        padding: 1rem 1.25rem;
    }
    
    .card-content {
        padding: 0 1.25rem;
    }
    
    .card-content.active {
        padding: 1.25rem;
    }
    
    main {
        padding: 1.5rem 0;
    }
    
    .troubleshooting-section:first-of-type {
        margin-top: 1rem;
    }
    
    .contact-section {
        margin-top: 3rem;
        margin-bottom: 1.5rem;
    }
    
    .contact-box {
        padding: 2rem 1.5rem;
    }
    
    .contact-box h2 {
        font-size: 1.75rem;
    }
    
    .contact-box p {
        font-size: 1rem;
    }
    
    .contact-instruction {
        font-size: 1.05rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    header h1 {
        font-size: 1.75rem;
    }
    
    .card-header {
        font-size: 1rem;
        padding: 0.9rem 1rem;
    }
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}