* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

body {
    background-color: #fafafa;
    color: #1a1a1a;
    line-height: 1.5;
}

.top-nav {
    position: fixed;
    top: 32px;
    right: 36px;
    z-index: 100;
}
.top-nav a {
    font-size: 13px;
    font-weight: 500;
    color: #1a1a1a;
    text-decoration: none;
}

.container {
    max-width: 980px;
    width: 100%;
    margin: 80px auto 0;
    padding: 0 24px;
}

.header {
    text-align: center;
    margin-bottom: 80px;
}
.header h1 {
    font-size: 36px;
    font-weight: 600;
    color: #000;
    margin-bottom: 14px;
}
.header p {
    font-size: 16px;
    color: #666;
}

.tool-container {
    max-width: 680px;
    margin: 0 auto;
    background: #fff;
    border: 1px solid #eee;
    border-radius: 24px;
    padding: 2rem;
}
.form-group {
    margin-bottom: 1.5rem;
}
label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: #1a1a1a;
}
textarea, select {
    width: 100%;
    padding: 12px;
    border: 1px solid #e0e0e0;
    border-radius: 16px;
    font-size: 14px;
    font-family: inherit;
}
textarea:focus, select:focus {
    outline: none;
    border-color: #aaa;
}
.generate-btn {
    width: 100%;
    padding: 12px;
    background: #1a1a1a;
    color: white;
    border: none;
    border-radius: 16px;
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}
.generate-btn:hover {
    background: #333;
}
.result-area {
    margin-top: 1.5rem;
    display: none;
}
.result-box {
    background: #f8f8f8;
    border-radius: 16px;
    padding: 1rem;
    border: 1px solid #eee;
    white-space: pre-wrap;
    font-size: 13px;
    line-height: 1.5;
    max-height: 400px;
    overflow-y: auto;
}
.copy-btn {
    background: transparent;
    border: 1px solid #1a1a1a;
    border-radius: 30px;
    padding: 6px 20px;
    font-size: 12px;
    font-weight: 500;
    cursor: pointer;
    margin-top: 12px;
    color: #1a1a1a;
}
.copy-btn:hover {
    background: #1a1a1a;
    color: white;
}
.back-link {
    margin-top: 40px;
    text-align: center;
}
.back-link a {
    font-size: 13px;
    color: #1a1a1a;
    text-decoration: none;
    border-bottom: 1px solid #ddd;
}
.toast {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    background: #2c3e50;
    color: white;
    padding: 8px 16px;
    border-radius: 40px;
    font-size: 13px;
    opacity: 0;
    transition: opacity 0.2s;
    pointer-events: none;
    z-index: 1000;
}

@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }
    .tool-container {
        padding: 1.2rem;
    }
    .header h1 {
        font-size: 28px;
    }
}