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

body {
    font-family: 'Segoe UI', 'Malgun Gothic', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 40px 20px;
    color: #333;
}

.container { max-width: 800px; margin: 0 auto; }

.back-link {
    display: inline-block;
    color: white;
    text-decoration: none;
    margin-bottom: 20px;
    font-weight: 600;
    font-size: 15px;
}
.back-link:hover { text-decoration: underline; }

.home-btn-wrap {
    display: flex;
    justify-content: center;
    margin-top: 24px;
}

.home-btn {
    display: inline-block;
    padding: 14px 36px;
    border-radius: 10px;
    background: #ffffff;
    color: #667eea;
    text-decoration: none;
    font-weight: 700;
    font-size: 16px;
    border: 2px solid #ffffff;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
    transition: transform 0.2s, background 0.2s, color 0.2s;
}
.home-btn:hover {
    transform: translateY(-2px);
    background: #667eea;
    color: #ffffff;
    border-color: #667eea;
}

.manual-card {
    background: white;
    border-radius: 16px;
    padding: 40px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.15);
}

h1 { font-size: 32px; color: #333; margin-bottom: 8px; }

.subtitle {
    font-size: 15px;
    color: #667eea;
    margin-bottom: 24px;
    font-weight: 600;
}

.description {
    font-size: 16px;
    color: #555;
    line-height: 1.7;
    margin-bottom: 24px;
}

h2 {
    font-size: 22px;
    color: #333;
    margin-top: 36px;
    margin-bottom: 16px;
    padding-bottom: 8px;
    border-bottom: 2px solid #f0f0f0;
}

.feature-list { list-style: none; padding: 0; }
.feature-list li {
    padding: 10px 0 10px 28px;
    position: relative;
    color: #555;
    line-height: 1.6;
}
.feature-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    top: 10px;
    color: #667eea;
    font-weight: 700;
    font-size: 18px;
}

.usage-steps { counter-reset: step; list-style: none; padding: 0; }
.usage-steps li {
    padding: 16px 16px 16px 56px;
    position: relative;
    background: #f8f9fa;
    border-radius: 8px;
    margin-bottom: 10px;
    color: #555;
    line-height: 1.6;
}
.usage-steps li::before {
    counter-increment: step;
    content: counter(step);
    position: absolute;
    left: 14px;
    top: 14px;
    width: 28px;
    height: 28px;
    background: #667eea;
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 14px;
}

.install-box {
    background: #f8f9fa;
    border: 2px solid #e9ecef;
    border-radius: 12px;
    padding: 20px;
    margin-top: 16px;
}

.button-group { display: flex; gap: 12px; flex-wrap: wrap; }

.install-btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 8px;
    text-decoration: none;
    font-size: 15px;
    font-weight: 600;
    color: white;
    transition: transform 0.2s, box-shadow 0.2s;
}
.install-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
}
.install-btn.chrome { background: #4285f4; }
.install-btn.edge { background: #0078d4; }
.install-btn.whale { background: #00c3a9; }
.install-btn.android { background: #3ddc84; }
.install-btn.iphone { background: #333; }

.tip-box {
    background: #fff8e1;
    border-left: 4px solid #ffc107;
    padding: 14px 18px;
    border-radius: 6px;
    margin: 16px 0;
    color: #555;
    line-height: 1.6;
}

.shortcut-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 12px;
    font-size: 15px;
}
.shortcut-table th,
.shortcut-table td {
    padding: 10px 14px;
    text-align: left;
    border-bottom: 1px solid #eee;
    color: #555;
}
.shortcut-table th {
    background: #f8f9fa;
    font-weight: 600;
    color: #333;
}
.shortcut-table code {
    background: #eef;
    padding: 2px 8px;
    border-radius: 4px;
    font-family: Consolas, monospace;
    font-size: 13px;
    color: #4051b5;
}

@media (max-width: 600px) {
    body { padding: 20px 10px; }
    .manual-card { padding: 24px 20px; }
    h1 { font-size: 24px; }
    h2 { font-size: 18px; }
    .button-group { flex-direction: column; }
    .install-btn { text-align: center; }
}