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

body {
    font-family: "Open Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
    line-height: 1.5;
    color: #404040;
    background: #fff;
    min-height: 100vh;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 24px;
    background: #EAEAEA;
    border-bottom: 1px solid #DDDDDD;
    font-size: 14px;
}

nav a {
    color: #404040;
    text-decoration: none;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.0625rem;
    font-size: 0.8125rem;
}

nav a:hover {
    color: #0085A1;
}

main {
    max-width: 720px;
    margin: 0 auto;
    padding: 48px 24px;
}

h1 {
    font-family: "Open Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 8px;
}

.subtitle {
    color: #808080;
    font-size: 16px;
    margin-bottom: 40px;
    font-style: italic;
}

.ai-note {
    color: #808080;
    font-size: 12px;
    margin-top: -32px;
    margin-bottom: 40px;
}

.tool-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.tool-card {
    display: block;
    padding: 20px 24px;
    background: #fff;
    border: 1px solid #DDDDDD;
    border-radius: 8px;
    text-decoration: none;
    color: inherit;
    transition: box-shadow 0.15s, border-color 0.15s;
}

.tool-card:hover {
    border-color: #0085A1;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
}

.tool-card h2 {
    font-size: 18px;
    font-weight: 800;
    margin-bottom: 4px;
    color: #404040;
}

.tool-card p {
    font-size: 14px;
    color: #808080;
}

.footer-note {
    margin-top: 48px;
    padding-top: 16px;
    border-top: 1px solid #DDDDDD;
    font-size: 13px;
    color: #808080;
    font-style: italic;
}

.footer-note a {
    color: #008AFF;
    text-decoration: none;
}

.footer-note a:hover {
    color: #0085A1;
    text-decoration: underline;
}

@media (max-width: 600px) {
    main {
        padding: 24px 16px;
    }
    nav {
        padding: 8px 16px;
    }
}