body {
    font-family: Arial, sans-serif;
    background-color: #f4f7f6;
    margin: 0;
    color: #333;
}
header {
    background-color: #008c75;
    color: white;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
header h1 { margin: 0; font-size: 1.5em; }
header .user-info a { color: #fff; text-decoration: none; margin-left: 1rem; }

main {
    padding: 2rem;
    max-width: 900px;
    margin: 0 auto;
}

.part-title {
    font-size: 1.8em;
    color: #333;
    border-bottom: 2px solid #008c75;
    padding-bottom: 0.5rem;
    margin-top: 2rem;
    margin-bottom: 1.5rem;
}

.module {
    background-color: #fff;
    border-radius: 8px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.module-header {
    font-size: 1.4em;
    font-weight: bold;
    color: #005a4b;
}
.module-header span {
    display: block;
    font-size: 0.8em;
    color: #555;
    font-weight: normal;
}

.topics-list {
    list-style: none;
    padding: 0;
    margin-top: 1rem;
}
.topic-item {
    display: flex;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid #eee;
}
.topic-item:last-child {
    border-bottom: none;
}
.topic-item input[type="checkbox"] {
    margin-right: 1rem;
    width: 18px;
    height: 18px;
    cursor: pointer;
    flex-shrink: 0;
}
.topic-item label {
    flex-grow: 1;
    cursor: pointer;
}
.topic-item.completed label {
    text-decoration: line-through;
    color: #888;
}

.topic-type {
    font-size: 0.8em;
    padding: 0.2em 0.6em;
    border-radius: 4px;
    color: white;
    margin-left: 1rem;
    white-space: nowrap;
}
.topic-type.Conteúdo { background-color: #3498db; }
.topic-type.Exemplo { background-color: #2ecc71; }
.topic-type.Exercício { background-color: #f1c40f; color: #333; }

.auth-container {
    width: 320px;
    padding: 2rem;
    margin: 100px auto;
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    text-align: center;
}
.auth-container input {
    width: 100%;
    padding: 10px;
    margin-bottom: 1rem;
    border: 1px solid #ccc;
    border-radius: 4px;
    box-sizing: border-box;
}
.auth-container button {
    width: 100%;
    padding: 10px;
    border: none;
    background-color: #008c75;
    color: white;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1em;
}
.auth-container .error {
    color: #e74c3c;
    background-color: #fbecec;
    border: 1px solid #e74c3c;
    padding: 10px;
    border-radius: 4px;
    margin-bottom: 1rem;
}
.loading { text-align: center; font-size: 1.2em; color: #555; }