/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --background: #ffffff;
    --surface: #f8fafc;
    --border: #e5e7eb;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --border-radius: 12px;
    --transition: all 0.3s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.container {
    width: 100%;
    max-width: 500px;
    padding: 2rem;
}

.content {
    background: var(--background);
    padding: 3rem 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    text-align: center;
    transform: translateY(0);
    transition: var(--transition);
}

.content:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.icon-wrapper {
    margin-bottom: 1.5rem;
}

.hello-icon {
    width: 64px;
    height: 64px;
    color: var(--primary-color);
    stroke-width: 1.5;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-10px); }
}

.title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--primary-color), #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow);
}

.btn:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn:active {
    transform: translateY(0);
}

.btn i {
    width: 20px;
    height: 20px;
    stroke-width: 2;
}

.message {
    margin-top: 1.5rem;
    padding: 1rem;
    border-radius: var(--border-radius);
    background: var(--surface);
    border: 1px solid var(--border);
    font-weight: 500;
    opacity: 0;
    transform: translateY(10px);
    transition: var(--transition);
}

.message.show {
    opacity: 1;
    transform: translateY(0);
}

/* Responsive design */
@media (max-width: 640px) {
    .container {
        padding: 1rem;
    }
    
    .content {
        padding: 2rem 1.5rem;
    }
    
    .title {
        font-size: 2rem;
    }
    
    .hello-icon {
        width: 48px;
        height: 48px;
    }
}

/* Print styles */
@media print {
    body {
        background: white;
        color: black;
    }
    
    .content {
        box-shadow: none;
        border: 1px solid #ccc;
    }
    
    .btn {
        display: none;
    }
}

@page {
    margin: 1in;
    @top-center {
        content: "Hello World";
    }
    @bottom-center {
        content: "Created by Helium";
    }
}