body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: #121212;
    color: #e0e0e0;
    margin: 0;
    padding: 20px;
    display: flex;
    justify-content: center;
}

.container {
    width: 100%;
    max-width: 900px;
    background-color: #1e1e1e;
    padding: 20px 30px;
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(0,0,0,0.5);
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid #333;
    padding-bottom: 15px;
    margin-bottom: 20px;
}

h2 {
    margin: 0;
    color: #ffffff;
}

h3 {
    color: #f39c12;
    border-bottom: 2px solid #f39c12;
    padding-bottom: 5px;
    margin-top: 30px;
}

a {
    color: #3498db;
    text-decoration: none;
    font-weight: bold;
}

a:hover {
    text-decoration: underline;
}

.balance { 
    padding: 15px; 
    margin: 10px 0; 
    font-weight: bold; 
    border-radius: 5px;
    display: flex;
    flex-direction: column;
    gap: 5px;
}
.positivo { background-color: #2e7d32; color: #d4edda; border-left: 5px solid #28a745; }
.negativo { background-color: #c62828; color: #f8d7da; border-left: 5px solid #dc3545; }

form {
    background-color: #1f1f1f;
    padding: 20px;
    border-radius: 5px;
    border: 1px solid #333;
    margin-top: 15px;
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
}
form.login-form, form.user-form, form.transaction-form {
    flex-direction: column;
}

.form-group {
    flex: 1 1 100%;
    display: flex;
    flex-direction: column;
}
label {
    margin-bottom: 5px;
    font-weight: bold;
    font-size: 0.9em;
    color: #ccc;
}

input[type="text"], input[type="password"], input[type="number"], select {
    padding: 10px;
    border: 1px solid #555;
    border-radius: 4px;
    font-size: 1em;
    background-color: #2c2c2c;
    color: #e0e0e0;
}

button {
    padding: 10px 15px;
    cursor: pointer;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 4px;
    font-size: 1em;
    font-weight: bold;
    transition: background-color 0.2s;
}
button:hover {
    background-color: #2980b9;
}
button.delete-btn {
    background-color: #e74c3c;
    padding: 5px 10px;
    font-size: 0.8em;
}
button.delete-btn:hover {
    background-color: #c0392b;
}

.error {
    color: #f8d7da;
    background-color: #c62828;
    padding: 10px;
    border-radius: 4px;
    text-align: center;
    margin-top: 15px;
}

.table-container { 
    max-height: 400px; 
    overflow-y: auto; 
    border: 1px solid #333;
    border-radius: 5px;
    margin-top: 15px;
}
table { 
    width: 100%; 
    border-collapse: collapse; 
}
th, td { 
    padding: 12px; 
    text-align: left; 
    border-bottom: 1px solid #333;
}
th { 
    background-color: #1a1a1a; 
    font-weight: bold;
    position: sticky;
    top: 0;
}
tr:nth-child(even) { background-color: #222; }
tr:hover { background-color: #333; }
td:last-child { text-align: center; }