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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.8;
    color: #333;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background: white;
    border-radius: 12px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #2980B9 0%, #1e5a8e 100%);
    color: white;
    padding: 20px 20px;
    text-align: center;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
}

.app-icon {
    width: 60px;
    height: 60px;
    border-radius: 12px;
}

header p {
    margin-bottom: 0;
}

h1 {
    font-size: 1.8em;
    margin-bottom: 5px;
    font-weight: 700;
    letter-spacing: 0.5px;
}

h2 {
    color: #2980B9;
    font-size: 1.4em;
    margin: 20px 0 12px 0;
    padding-bottom: 8px;
    border-bottom: 2px solid #2980B9;
}

h3 {
    color: #34495e;
    font-size: 1.1em;
    margin: 15px 0 8px 0;
}

h4 {
    color: #555;
    font-size: 0.95em;
    margin: 12px 0 6px 0;
    font-weight: 600;
}

main {
    padding: 25px 20px;
}

nav#table-of-contents {
    background: #ecf0f1;
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 25px;
}

nav#table-of-contents h2 {
    color: #2980B9;
    font-size: 1.2em;
    margin: 0 0 10px 0;
    padding-bottom: 8px;
    border-bottom: 2px solid #2980B9;
}

nav#table-of-contents ul {
    list-style: none;
    columns: 1;
    column-gap: 0;
}

nav#table-of-contents li {
    margin-bottom: 6px;
}

nav#table-of-contents a {
    color: #2980B9;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

nav#table-of-contents a:hover {
    color: #1e5a8e;
    text-decoration: underline;
}

section {
    margin-bottom: 25px;
    scroll-margin-top: 20px;
}

p {
    margin-bottom: 12px;
    text-align: justify;
}

ul {
    margin-left: 18px;
    margin-bottom: 12px;
}

li {
    margin-bottom: 10px;
    line-height: 1.8;
}

strong {
    color: #2980B9;
    font-weight: 600;
}

a {
    color: #2980B9;
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: #1e5a8e;
    text-decoration: underline;
}

footer {
    background: #34495e;
    color: white;
    padding: 15px 20px;
    text-align: center;
    font-size: 0.85em;
}

@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    .container {
        border-radius: 8px;
    }

    header {
        padding: 15px 15px;
    }

    .header-content {
        gap: 10px;
    }

    .app-icon {
        width: 50px;
        height: 50px;
    }

    h1 {
        font-size: 1.5em;
    }

    h2 {
        font-size: 1.2em;
        margin: 15px 0 10px 0;
    }

    h3 {
        font-size: 1em;
        margin: 12px 0 7px 0;
    }

    main {
        padding: 15px 15px;
    }

    nav#table-of-contents {
        padding: 12px;
        margin-bottom: 15px;
    }

    nav#table-of-contents h2 {
        font-size: 1.1em;
        margin: 0 0 8px 0;
    }

    nav#table-of-contents li {
        margin-bottom: 5px;
    }

    section {
        margin-bottom: 15px;
    }

    p {
        margin-bottom: 10px;
        font-size: 0.95em;
    }

    ul {
        margin-left: 15px;
        margin-bottom: 10px;
    }

    li {
        margin-bottom: 7px;
    }
}