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

:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --success-color: #27ae60;
    --danger-color: #e74c3c;
    --warning-color: #f39c12;
    --background: #ecf0f1;
    --card-background: #ffffff;
    --text-primary: #2c3e50;
    --text-secondary: #7f8c8d;
    --border-color: #bdc3c7;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    text-align: center;
    padding: 40px 0;
}

header h1 {
    color: var(--primary-color);
    font-size: 2.5rem;
    margin-bottom: 10px;
}

header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

main {
    flex: 1;
}

.view {
    display: none;
}

.view.active {
    display: block;
}

.card {
    background: var(--card-background);
    border-radius: 8px;
    padding: 30px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.card h2 {
    color: var(--primary-color);
    margin-bottom: 25px;
    font-size: 1.8rem;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-primary);
    font-weight: 500;
}

.form-group input[type="text"],
.form-group input[type="password"],
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.3s;
}

.form-group input[type="text"]:focus,
.form-group input[type="password"]:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--secondary-color);
}

.form-group textarea {
    resize: vertical;
    font-family: 'Courier New', monospace;
}

.form-group small {
    display: block;
    margin-top: 5px;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.ttl-group {
    display: flex;
    gap: 15px;
}

.ttl-input {
    flex: 1;
    display: flex;
    align-items: center;
    gap: 8px;
}

.ttl-input input {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
}

.ttl-input span {
    color: var(--text-secondary);
    white-space: nowrap;
    font-size: 0.95rem;
}

.url-container {
    display: flex;
    gap: 10px;
}

.url-container input {
    flex: 1;
}

.btn-primary,
.btn-secondary {
    padding: 12px 24px;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.1s;
    font-weight: 500;
}

.btn-primary {
    background-color: var(--secondary-color);
    color: white;
    width: 100%;
}

.btn-primary:hover {
    background-color: #2980b9;
}

.btn-primary:active {
    transform: scale(0.98);
}

.btn-secondary {
    background-color: var(--primary-color);
    color: white;
}

.btn-secondary:hover {
    background-color: #34495e;
}

.info-box {
    background-color: #e8f4fd;
    border-left: 4px solid var(--secondary-color);
    padding: 15px;
    margin: 20px 0;
    border-radius: 4px;
}

.info-box.warning {
    background-color: #fff3cd;
    border-left-color: var(--warning-color);
}

.info-box strong {
    display: block;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.info-box ul {
    margin-left: 20px;
}

.info-box li {
    margin: 5px 0;
}

.secret-display,
.error-display {
    display: none;
}

.secret-display.active,
.error-display.active {
    display: block;
}

.secret-display textarea {
    background-color: #f8f9fa;
}

.meta-info {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.meta-info div {
    margin: 5px 0;
}

.error-display {
    background-color: #fee;
    border-left: 4px solid var(--danger-color);
    padding: 15px;
    border-radius: 4px;
    color: var(--danger-color);
}

footer {
    text-align: center;
    padding: 30px 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

@media (max-width: 600px) {
    header h1 {
        font-size: 2rem;
    }

    .card {
        padding: 20px;
    }

    .ttl-group {
        flex-direction: column;
        gap: 10px;
    }

    .url-container {
        flex-direction: column;
    }
}