:root {
    --primary-color: #3498db;
    --secondary-color: #2ecc71;
    --background-color: #f0f2f5;
    --text-color: #333;
    --card-background: #fff;
}

body {
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: var(--background-color);
    color: var(--text-color);
    transition: all 0.3s ease;
    text-align: center;
}

.container {
    max-width: 1000px;
    margin: 40px auto;
    padding: 20px;
    text-align: center;
}

h1, h2 {
    text-align: center;
    color: var(--primary-color);
    margin-bottom: 30px;
}

.tabs {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 30px;
}

.tab {
    padding: 12px 24px;
    background-color: var(--primary-color);
    color: white;
    cursor: pointer;
    border: none;
    border-radius: 30px;
    margin: 5px;
    transition: all 0.3s ease;
    font-weight: bold;
    text-transform: uppercase;
    letter-spacing: 1px;
    text-align: center;
    text-decoration: none;
}

.tab:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
}

.tab.active {
    background-color: var(--secondary-color);
}

.tab-content {
    display: none;
    background-color: var(--card-background);
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
    text-align: center;
}

input[type="file"] {
    display: none;
}

.file-label {
    display: block;
    width: 100%;
    max-width: 300px;
    margin: 0 auto 20px auto;
    padding: 15px 20px;
    background-color: var(--primary-color);
    color: white;
    cursor: pointer;
    border-radius: 30px;
    text-align: center;
    transition: all 0.3s ease;
    font-weight: bold;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.file-label:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
}

#file-list, #pdf-info {
    margin-top: 20px;
    padding: 15px;
    border: 1px solid #ddd;
    border-radius: 10px;
    max-height: 200px;
    overflow-y: auto;
    text-align: left;
}

button {
    display: block;
    width: 100%;
    max-width: 300px;
    margin: 20px auto 0 auto;
    padding: 15px;
    background-color: var(--secondary-color);
    color: white;
    border: none;
    border-radius: 30px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: bold;
    text-transform: uppercase;
    letter-spacing: 1px;
    text-align: center;
}

button:hover {
    background-color: #27ae60;
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
}

button:disabled {
    background-color: #95a5a6;
    cursor: not-allowed;
}

#convert-button, #compress-button, #merge-button, #remove-page-button {
    display: block;
    margin: 0 auto;
    text-align: center;
}

#error-message {
    color: #e74c3c;
    text-align: center;
    margin-top: 20px;
    font-weight: bold;
}

input[type="number"], select, input[type="text"] {
    width: 100%;
    padding: 12px;
    margin-top: 10px;
    margin-bottom: 10px;
    border: 1px solid #ddd;
    border-radius: 30px;
    transition: all 0.3s ease;
    text-align: center;
}

input[type="number"]:focus, select:focus, input[type="text"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.2);
}

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

    h1 {
        font-size: 24px;
    }

    .tab {
        padding: 10px 15px;
        font-size: 14px;
    }

    button {
        width: 100%;
        margin: 10px 0;
    }
}

footer {
    background-color: var(--background-color);
    padding: 20px;
    margin-top: 40px;
    border-top: 1px solid #ddd;
    text-align: center;
}

.terms-of-use {
    max-width: 800px;
    margin: 0 auto;
    text-align: left;
}

.terms-of-use h2 {
    color: var(--primary-color);
    margin-bottom: 15px;
}

.terms-of-use p {
    margin-bottom: 10px;
}

.terms-of-use ul {
    list-style-type: disc;
    padding-left: 20px;
}

.terms-of-use ul li {
    margin-bottom: 10px;
}

.other-tools {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 30px;
}

.other-tools .tab {
    padding: 12px 24px;
    background-color: var(--secondary-color);
    color: white;
    cursor: pointer;
    border: none;
    border-radius: 30px;
    margin: 5px;
    transition: all 0.3s ease;
    font-weight: bold;
    text-transform: uppercase;
    letter-spacing: 1px;
    text-align: center;
    text-decoration: none;
}

.other-tools .tab:hover {
    background-color: #27ae60;
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
}

.other-tools .tab.active {
    background-color: var(--primary-color);
}