:root {
    --primary: #1a365d;
    --primary-light: #2c5282;
    --accent: #3182ce;
    --success: #276749;
    --success-bg: #f0fff4;
    --error: #9b2c2c;
    --error-bg: #fff5f5;
    --info-bg: #ebf8ff;
    --gray-50: #f7fafc;
    --gray-100: #edf2f7;
    --gray-200: #e2e8f0;
    --gray-600: #718096;
    --gray-800: #2d3748;
    --white: #ffffff;
    --radius: 8px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--gray-50);
    color: var(--gray-800);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    background: var(--primary);
    color: var(--white);
    padding: 1rem 2rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.header-content {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header h1 { font-size: 1.25rem; font-weight: 600; }

#user-info {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 0.875rem;
}

main {
    flex: 1;
    max-width: 800px;
    margin: 2rem auto;
    padding: 0 1rem;
    width: 100%;
}

.card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
    margin-bottom: 1.5rem;
}

.card h2 { margin-bottom: 0.75rem; color: var(--primary); }
.card h3 { margin: 1.5rem 0 0.75rem; color: var(--primary-light); font-size: 1.1rem; }
.card p { margin-bottom: 0.75rem; line-height: 1.6; }
.card ul { margin-left: 1.5rem; margin-bottom: 0.75rem; line-height: 1.8; }

.btn {
    display: inline-block;
    padding: 0.6rem 1.2rem;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius);
    background: var(--white);
    color: var(--gray-800);
    font-size: 0.9rem;
    cursor: pointer;
    text-decoration: none;
    transition: background 0.15s, border-color 0.15s;
}
.btn:hover { background: var(--gray-100); border-color: var(--accent); }

.btn-primary {
    background: var(--accent);
    color: var(--white);
    border-color: var(--accent);
}
.btn-primary:hover { background: var(--primary-light); border-color: var(--primary-light); }

.btn-sm { padding: 0.3rem 0.8rem; font-size: 0.8rem; }

.info-box {
    background: var(--info-bg);
    border: 1px solid #bee3f8;
    border-radius: var(--radius);
    padding: 1rem 1.25rem;
    margin: 1rem 0;
}

.success-box {
    background: var(--success-bg);
    border: 1px solid #c6f6d5;
    border-radius: var(--radius);
    padding: 1rem 1.25rem;
    margin: 1rem 0;
}

.error-card { border-left: 4px solid var(--error); }
.error-card h2 { color: var(--error); }

code {
    background: var(--gray-100);
    padding: 0.15rem 0.4rem;
    border-radius: 3px;
    font-size: 0.85em;
    font-family: 'Menlo', 'Consolas', monospace;
}

pre {
    background: var(--gray-800);
    color: #e2e8f0;
    padding: 1rem;
    border-radius: var(--radius);
    overflow-x: auto;
    margin: 0.75rem 0;
}
pre code { background: none; color: inherit; padding: 0; }

.download-group {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin: 0.75rem 0;
}

.progress-bar {
    width: 100%;
    height: 6px;
    background: var(--gray-200);
    border-radius: 3px;
    margin: 1rem 0 0.5rem;
    overflow: hidden;
}
.progress-fill {
    height: 100%;
    background: var(--accent);
    border-radius: 3px;
    transition: width 0.3s ease;
    width: 0%;
}

#progress-text { font-size: 0.875rem; color: var(--gray-600); }

.hidden { display: none !important; }

footer {
    text-align: center;
    padding: 1.5rem;
    color: var(--gray-600);
    font-size: 0.8rem;
}

@media (max-width: 640px) {
    .header-content { flex-direction: column; gap: 0.5rem; text-align: center; }
    .download-group { flex-direction: column; }
}