:root {
    --bg-color: #0f172a;
    --primary-color: #1e293b;
    --secondary-color: #334155;
    --accent-color: #67e8f9;
    --accent-hover: #06b6d4;
    --text-color: #f1f5f9;
    --text-muted: #94a3b8;
    --success-color: #4ade80;
    --font-family: 'Poppins', sans-serif;
    --border-radius: 12px;
    --box-shadow: 0 8px 25px rgba(0, 0, 0, 0.4);
    --transition-speed: 0.2s;
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
    line-height: 1.6;
}

.container {
    background-color: var(--primary-color);
    padding: 40px;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    text-align: center;
    width: 100%;
    max-width: 650px;
    border: 1px solid var(--secondary-color);
}

header h1 {
    color: var(--accent-color);
    margin-bottom: 5px;
    font-weight: 600;
}

header p {
    color: var(--text-muted);
    margin-bottom: 10px;
    font-weight: 300;
}

header .credit {
    font-size: 0.8em;
    margin-bottom: 30px;
}

header .credit a {
    color: var(--accent-color);
    text-decoration: none;
    transition: color var(--transition-speed) ease;
}

header .credit a:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

main {
    margin-top: 30px;
}

.btn {
    padding: 12px 25px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-family: var(--font-family);
    font-size: 1rem;
    font-weight: 400;
    transition: all var(--transition-speed) ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    box-shadow: 0 3px 8px rgba(0, 0, 0, 0.25);
}

.btn i {
    color: inherit;
    background: transparent;
    line-height: 1;
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.3);
}

.btn:active {
    transform: translateY(0px);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
}

.btn-generate {
    background: linear-gradient(45deg, var(--accent-color), var(--accent-hover));
    color: var(--bg-color);
    font-size: 1.1rem;
    font-weight: 600;
    min-width: 200px;
    margin-bottom: 30px;
}

.btn-generate:hover {
    box-shadow: 0 8px 25px rgba(103, 232, 249, 0.6);
}

/* Removed all spinner/loading animations */

.key-display-area {
    margin-top: 0;
    background-color: var(--secondary-color);
    padding: 25px;
    border-radius: var(--border-radius);
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.2);
    width: 100%;
}

.key-box {
    display: flex;
    align-items: center;
    background-color: var(--bg-color);
    padding: 12px;
    border-radius: var(--border-radius);
    width: 100%;
    min-height: 60px;
    overflow-x: auto;
    scrollbar-width: thin;
    scrollbar-color: var(--accent-color) transparent;
}

.key-box::-webkit-scrollbar {
    height: 4px;
}

.key-box::-webkit-scrollbar-thumb {
    background-color: var(--accent-color);
    border-radius: 2px;
}

#serialKey {
    flex: 1;
    min-width: 0;
    padding: 10px 12px;
    border: 1px solid var(--primary-color);
    background-color: transparent;
    color: var(--text-color);
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.9rem;
    font-weight: 600;
    border-radius: var(--border-radius);
    outline: none;
    white-space: nowrap;
    overflow-x: auto;
    scrollbar-width: none;
}

#serialKey::-webkit-scrollbar {
    display: none;
}

.btn-icon {
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.1);
    padding: 10px;
    color: var(--text-color);
    font-size: 1rem;
    flex-shrink: 0;
    margin-left: 8px;
}

.btn-icon:hover {
    background-color: rgba(255, 255, 255, 0.2);
}

.copy-feedback {
    display: block;
    margin-top: 10px;
    font-size: 0.9em;
    color: var(--success-color);
    height: 1.2em;
    opacity: 0;
    transition: opacity var(--transition-speed) ease;
}

.copy-feedback.visible {
    opacity: 1;
}

footer {
    margin-top: 40px;
    color: var(--text-muted);
    font-size: 0.8em;
}

@media (max-width: 600px) {
    .container {
        padding: 20px;
    }
    
    #serialKey {
        font-size: 0.8rem;
        padding: 8px 10px;
    }
    
    .btn-icon {
        padding: 8px;
    }
    
    .key-display-area {
        padding: 15px;
    }
}