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

:root {
    --primary-color: #6366f1;
    --secondary-color: #8b5cf6;
    --text-color: #1f2937;
    --text-light: #6b7280;
    --bg-color: #ffffff;
    --bg-light: #f9fafb;
    --border-color: #e5e7eb;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-light);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 60px 0;
    text-align: center;
    box-shadow: var(--shadow-lg);
}

header h1 {
    font-size: 3rem;
    margin-bottom: 10px;
    font-weight: 700;
}

.subtitle {
    font-size: 1.25rem;
    opacity: 0.9;
}

/* Main Content */
main {
    padding: 40px 20px;
}

.intro {
    text-align: center;
    margin-bottom: 50px;
}

.intro h2 {
    font-size: 2rem;
    margin-bottom: 15px;
    color: var(--text-color);
}

.intro p {
    font-size: 1.1rem;
    color: var(--text-light);
    max-width: 800px;
    margin: 0 auto;
}

/* Platform Cards Grid */
.platforms-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-bottom: 50px;
}

.platform-card {
    background: var(--bg-color);
    border-radius: 12px;
    padding: 30px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.platform-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.platform-icon {
    font-size: 4rem;
    margin-bottom: 20px;
}

.platform-card h3 {
    font-size: 1.5rem;
    margin-bottom: 10px;
    color: var(--text-color);
}

.platform-card p {
    color: var(--text-light);
    margin-bottom: 20px;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    background: var(--primary-color);
    color: white;
    text-decoration: none;
    border-radius: 8px;
    font-weight: 600;
    transition: background 0.3s ease;
}

.btn:hover {
    background: var(--secondary-color);
}

/* Tips Section */
.tips {
    background: var(--bg-color);
    padding: 30px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-top: 40px;
}

.tips h2 {
    font-size: 1.75rem;
    margin-bottom: 20px;
    color: var(--text-color);
}

.tips ul {
    list-style: none;
    padding-left: 0;
}

.tips li {
    padding: 10px 0;
    padding-left: 30px;
    position: relative;
    color: var(--text-light);
}

.tips li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

/* Tutorial Page Styles */
.tutorial-header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 40px 0;
    margin-bottom: 40px;
}

.tutorial-header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

.back-link {
    display: inline-block;
    margin-bottom: 20px;
    color: white;
    text-decoration: none;
    opacity: 0.9;
    transition: opacity 0.3s ease;
}

.back-link:hover {
    opacity: 1;
}

.tutorial-content {
    background: var(--bg-color);
    padding: 40px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 40px;
}

.step {
    margin-bottom: 40px;
    padding-bottom: 30px;
    border-bottom: 2px solid var(--border-color);
}

.step:last-child {
    border-bottom: none;
}

.step-number {
    display: inline-block;
    width: 40px;
    height: 40px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    text-align: center;
    line-height: 40px;
    font-weight: bold;
    margin-right: 15px;
    font-size: 1.2rem;
}

.step h2 {
    display: inline-block;
    font-size: 1.5rem;
    color: var(--text-color);
    vertical-align: middle;
}

.step-content {
    margin-top: 20px;
    padding-left: 55px;
}

.step-content p {
    margin-bottom: 15px;
    color: var(--text-light);
    line-height: 1.8;
}

.step-content ul {
    margin: 15px 0;
    padding-left: 30px;
}

.step-content li {
    margin-bottom: 10px;
    color: var(--text-light);
}

.highlight {
    background: #fef3c7;
    padding: 2px 6px;
    border-radius: 4px;
    font-weight: 600;
}

.warning {
    background: #fee2e2;
    border-left: 4px solid #ef4444;
    padding: 15px;
    margin: 20px 0;
    border-radius: 4px;
}

.warning strong {
    color: #dc2626;
}

/* Footer */
footer {
    background: var(--text-color);
    color: white;
    text-align: center;
    padding: 30px 0;
    margin-top: 60px;
}

/* Responsive */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .platforms-grid {
        grid-template-columns: 1fr;
    }

    .tutorial-content {
        padding: 20px;
    }

    .step-content {
        padding-left: 0;
    }
}