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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    background-color: #ffffff;
    color: #000000;
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    padding: 40px 0;
    border-bottom: 2px solid #000000;
    margin-bottom: 40px;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    font-weight: 700;
}

header p {
    font-size: 1.1rem;
    color: #333333;
}

main {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.input-section {
    display: flex;
    flex-direction: column;
}

label {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 10px;
}

textarea,
input[type="text"] {
    width: 100%;
    padding: 15px;
    font-family: 'Courier New', monospace;
    font-size: 14px;
    border: 2px solid #000000;
    background-color: #ffffff;
    color: #000000;
}

textarea {
    resize: vertical;
}

textarea:focus,
input[type="text"]:focus {
    outline: none;
    border: 2px solid #000000;
}

.output-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.output-panel {
    border: 2px solid #000000;
    padding: 20px;
    background-color: #ffffff;
}

.output-panel h2 {
    font-size: 1.3rem;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid #000000;
}

pre {
    font-family: 'Courier New', monospace;
    font-size: 13px;
    white-space: pre-wrap;
    word-wrap: break-word;
    color: #000000;
    background-color: #f5f5f5;
    padding: 15px;
    border: 1px solid #000000;
    min-height: 100px;
}

.error-message {
    padding: 15px;
    border: 2px solid #000000;
    background-color: #ffffff;
    color: #000000;
    display: none;
}

.error-message.show {
    display: block;
}

.signature-status {
    margin-top: 15px;
    padding: 12px;
    font-weight: 600;
    font-size: 14px;
    border: 2px solid #000000;
    display: none;
}

.signature-status.valid {
    display: block;
    background-color: #d4edda;
    color: #155724;
    border-color: #28a745;
}

.signature-status.invalid {
    display: block;
    background-color: #f8d7da;
    color: #721c24;
    border-color: #dc3545;
}

.signature-status.info {
    display: block;
    background-color: #d1ecf1;
    color: #0c5460;
    border-color: #17a2b8;
}

.main-nav {
    margin-top: 20px;
    padding-top: 15px;
    border-top: 1px solid #000000;
}

.main-nav a {
    color: #000000;
    text-decoration: none;
    padding: 8px 16px;
    margin: 0 5px;
    border: 1px solid #000000;
    display: inline-block;
    font-weight: 500;
}

.guide-section {
    margin-top: 60px;
    padding: 40px 0;
    border-top: 2px solid #000000;
}

.guide-section h2 {
    font-size: 2rem;
    margin-bottom: 30px;
    text-align: center;
}

.guide-section h3 {
    font-size: 1.3rem;
    margin-bottom: 10px;
    margin-top: 25px;
}

.guide-content {
    margin-bottom: 30px;
}

.guide-step {
    margin-bottom: 30px;
}

.guide-step p,
.guide-content p {
    margin-bottom: 10px;
    line-height: 1.8;
}

.guide-step ul,
.guide-content ul {
    margin-left: 30px;
    margin-bottom: 10px;
}

.guide-step li,
.guide-content li {
    margin-bottom: 8px;
    line-height: 1.6;
}

footer {
    text-align: center;
    padding: 40px 0 20px;
    margin-top: 60px;
    border-top: 2px solid #000000;
    color: #333333;
}

.footer-nav {
    margin-bottom: 20px;
}

.footer-nav a {
    color: #000000;
    text-decoration: none;
    padding: 5px 15px;
    margin: 0 5px;
    border-bottom: 1px solid #000000;
    display: inline-block;
}

.content-section {
    padding: 20px 0;
}

.content-section h2 {
    font-size: 1.8rem;
    margin-top: 40px;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid #000000;
}

.content-section h2:first-child {
    margin-top: 0;
}

.content-section h3 {
    font-size: 1.3rem;
    margin-top: 25px;
    margin-bottom: 10px;
}

.content-section p {
    margin-bottom: 15px;
    line-height: 1.8;
}

.content-section ul {
    margin-left: 30px;
    margin-bottom: 15px;
}

.content-section li {
    margin-bottom: 10px;
    line-height: 1.6;
}

.content-section a {
    color: #000000;
    text-decoration: underline;
}

.faq-item {
    margin-bottom: 40px;
    padding-bottom: 30px;
    border-bottom: 1px solid #cccccc;
}

.faq-item:last-child {
    border-bottom: none;
}

.faq-item h2 {
    font-size: 1.4rem;
    margin-bottom: 10px;
    border-bottom: none;
}

.contact-method {
    margin-bottom: 35px;
    padding: 20px;
    border: 1px solid #000000;
    background-color: #fafafa;
}

.contact-note {
    margin-top: 40px;
    padding: 20px;
    border: 2px solid #000000;
    background-color: #f5f5f5;
    text-align: center;
}

@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    .output-section {
        grid-template-columns: 1fr;
    }

    .main-nav a {
        display: block;
        margin: 5px 0;
    }
}