body {
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(145deg, #fa5d48, #8b4be3, #007b6e);
    background-size: cover;
    background-attachment: fixed;
    color: #fff;
}

.container {
    max-width: 800px;
    margin: 3em auto 0;
    padding: 2em;
    background: rgba(0, 0, 0, 0.4);
    border-radius: 20px;
    box-shadow: 0 0 20px rgba(0,0,0,0.3);
}

header {
    text-align: center;
}

.logo {
    max-width: 120px;
    border-radius: 12px;
}

h1 {
    font-size: 3em;
    margin: 0.2em 0;
}

.subtitle {
    font-size: 1.3em;
    opacity: 0.9;
}

h2 {
    font-size: 2em;
    margin-top: 1em;
}

ul {
    text-align: left;
    padding-left: 1.2em;
    line-height: 1.8em;
}

.note {
    margin-top: 1em;
    font-size: 0.95em;
    opacity: 0.9;
}

.calc {
    text-align: left;
    margin: 1em auto;
    display: flex;
    flex-direction: column;
    gap: 0.5em;
    max-width: 400px;
}

.calc label select {
    width: 100%;
    margin-top: 0.3em;
    padding: 0.5em;
    border-radius: 8px;
    border: none;
    font-size: 1em;
}

button {
    background: #fff;
    color: #333;
    padding: 0.6em 1em;
    border: none;
    border-radius: 8px;
    font-size: 1em;
    cursor: pointer;
    transition: 0.3s ease;
}

button:hover {
    background: #f0f0f0;
}

.social-links {
    display: flex;
    flex-wrap: wrap;
    gap: 1em;
    justify-content: center;
    margin-top: 1em;
}

.social-links a {
    background: rgba(255, 255, 255, 0.1);
    padding: 0.5em 1em;
    border-radius: 8px;
    color: #fff;
    text-decoration: none;
    transition: 0.3s ease;
}

.social-links a:hover {
    background: rgba(255, 255, 255, 0.25);
}

footer {
    text-align: center;
    margin-top: 3em;
    font-size: 0.9em;
    opacity: 0.8;
}

@media screen and (max-width: 600px) {
    .container {
        padding: 1em;
        margin-top: 1.5em;
    }
    .calc {
        max-width: 100%;
        font-size: 1em;
    }
    .social-links {
        flex-direction: column;
        align-items: center;
    }
    .logo {
        max-width: 100px;
    }
    h1 {
        font-size: 2em;
    }
}