/* CSS Custom Properties */
:root {
    --primary: #1976D2;
    --primary-dark: #1565C0;
    --primary-light: #42A5F5;
    --secondary: #424242;
    --background: #FAFAFA;
    --surface: #FFFFFF;
    --warning: #F57C00;
    --warning-light: #FFF3E0;
    --text-primary: #212121;
    --text-secondary: #757575;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.14);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1), 0 2px 4px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.1), 0 6px 10px rgba(0,0,0,0.08);
    --radius: 8px;
    --transition: 0.2s ease;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--background);
    min-height: 100vh;
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: white;
    padding: 2.5rem 1rem;
    text-align: center;
    box-shadow: var(--shadow-md);
}

.header h1 {
    font-size: 2rem;
    font-weight: 400;
    letter-spacing: 0.5px;
}

.header p {
    margin-top: 0.5rem;
    opacity: 0.9;
    font-size: 1rem;
}

/* Main Container */
.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 1.5rem;
}

/* Cards */
.card {
    background: var(--surface);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    padding: 1.5rem;
    margin-bottom: 1rem;
    transition: box-shadow var(--transition);
}

.card:hover {
    box-shadow: var(--shadow-md);
}

.card-title {
    font-size: 1.125rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.card-icon {
    font-size: 1.25rem;
}

/* Warning Card */
.card-warning {
    background: var(--warning-light);
    border-left: 4px solid var(--warning);
}

.card-warning .card-title {
    color: var(--warning);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.875rem 1.5rem;
    font-size: 0.9375rem;
    font-weight: 500;
    text-decoration: none;
    border-radius: var(--radius);
    border: none;
    cursor: pointer;
    transition: all var(--transition);
    min-height: 48px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.btn-primary {
    background: var(--primary);
    color: white;
    box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
    background: var(--primary-dark);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

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

.btn-secondary {
    background: var(--secondary);
    color: white;
    box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
    background: #333;
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.btn-outline {
    background: transparent;
    color: var(--primary);
    border: 2px solid var(--primary);
}

.btn-outline:hover {
    background: var(--primary);
    color: white;
}

/* Button Group */
.btn-group {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

@media (min-width: 480px) {
    .btn-group {
        flex-direction: row;
        flex-wrap: wrap;
    }

    .btn-group .btn {
        flex: 1;
        min-width: 200px;
    }
}

/* Info Row */
.info-row {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.5rem 0;
}

.info-icon {
    font-size: 1.25rem;
    color: var(--primary);
    width: 1.5rem;
    text-align: center;
}

.info-text {
    color: var(--text-secondary);
}

.info-link {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
}

.info-link:hover {
    text-decoration: underline;
}

/* Notice Text */
.notice-text {
    color: var(--text-secondary);
    line-height: 1.7;
}

.notice-text strong {
    color: var(--text-primary);
}

/* Code/Technical */
.code {
    font-family: "SF Mono", "Monaco", "Consolas", monospace;
    background: #E8E8E8;
    padding: 0.125rem 0.375rem;
    border-radius: 4px;
    font-size: 0.875em;
}

/* Divider */
.divider {
    height: 1px;
    background: #E0E0E0;
    margin: 1rem 0;
}

/* Footer */
.footer {
    text-align: center;
    padding: 1.5rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.footer a {
    color: var(--text-secondary);
    text-decoration: none;
}

.footer a:hover {
    color: var(--primary);
    text-decoration: underline;
}

/* Focus States for Accessibility */
.btn:focus,
.info-link:focus {
    outline: 2px solid var(--primary-light);
    outline-offset: 2px;
}

/* Responsive Adjustments */
@media (min-width: 600px) {
    .header {
        padding: 3rem 2rem;
    }

    .header h1 {
        font-size: 2.5rem;
    }

    .container {
        padding: 2rem;
    }

    .card {
        padding: 2rem;
    }
}

/* Print Styles */
@media print {
    .header {
        background: white;
        color: black;
        box-shadow: none;
    }

    .card {
        box-shadow: none;
        border: 1px solid #ccc;
    }

    .btn {
        border: 1px solid currentColor;
    }
}