:root {
    --background-color: #0d1117;
    --card-color: #161b22;
    --text-color: #e6edf3;
    --text-muted: #8b949e;
    --primary-color: #58a6ff;
    --primary-hover: #79c0ff;
    --border-color: #30363d;
    --font-family: 'Poppins', sans-serif;
}

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

body {
    background-color: var(--background-color);
    background-image: url('https://images.unsplash.com/photo-1574267432553-4b4628081c31?ixlib=rb-4.0.3&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D&auto=format&fit=crop&w=1931&q=80');
    background-size: cover;
    background-position: center;
    color: var(--text-color);
    font-family: var(--font-family);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    position: relative;
}

.background-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(13, 17, 23, 0.85);
    backdrop-filter: blur(5px);
}

.login-header {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    padding: 1.5rem 2rem;
}

.logo {
    color: var(--primary-color);
    font-weight: 700;
    font-size: 1.8rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    text-decoration: none;
}

.login-container {
    width: 100%;
    max-width: 450px;
    padding: 2rem;
    position: relative;
    z-index: 2;
}

.login-box {
    background-color: rgba(22, 27, 34, 0.8);
    border: 1px solid var(--border-color);
    padding: 3rem;
    border-radius: 8px;
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.5);
}

h1 {
    text-align: left;
    margin-bottom: 2rem;
    font-size: 2.5rem;
    color: var(--text-color);
    font-weight: 600;
}

.input-group {
    margin-bottom: 1.5rem;
}

input[type="text"],
input[type="password"] {
    width: 100%;
    padding: 1rem;
    background-color: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-color);
    font-size: 1rem;
    font-family: var(--font-family);
}

input[type="text"]::placeholder,
input[type="password"]::placeholder {
    color: var(--text-muted);
}

input[type="text"]:focus,
input[type="password"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.2);
}

.button-primary {
    width: 100%;
    background-color: var(--primary-color);
    color: var(--background-color);
    border: none;
    padding: 1rem;
    border-radius: 6px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    margin-top: 1rem;
}

.button-primary:hover {
    background-color: var(--primary-hover);
}

.button-primary:disabled {
    background-color: var(--primary-color);
    cursor: not-allowed;
    opacity: 0.7;
}

.error-message {
    color: #ffb3b3;
    text-align: center;
    margin-top: 1rem;
    opacity: 0;
    transition: opacity 0.3s ease-in-out;
    height: 1.2em; /* Reserve space to prevent layout shift */
}

.error-message.visible {
    opacity: 1;
}

@media (max-width: 576px) {
    .login-box {
        padding: 2rem;
        background-color: var(--background-color); /* On small screens, make it solid */
        border: none;
    }
    h1 {
        font-size: 2rem;
    }
}