/* ===========================================
   CmdSwitcher Landing Page Styles
   Optimized for performance and accessibility
   =========================================== */

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

:root {
    /* Colors */
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --bg-dark: #0f172a;
    --bg-section: #1e293b;
    --bg-card: #1e293b;
    --text: #f1f5f9;
    --text-muted: #94a3b8;
    --accent: #38bdf8;
    --success: #22c55e;
    --warning: #f59e0b;
    --danger: #ef4444;

    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Hiragino Sans", "Noto Sans JP", sans-serif;
    --font-mono: "SF Mono", Monaco, "Cascadia Code", monospace;

    /* Spacing */
    --section-padding: clamp(60px, 10vw, 100px);
    --container-max: 800px;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 200ms ease;
}

/* Accessibility: Skip Link */
.skip-link {
    position: absolute;
    top: -100%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary);
    color: white;
    padding: 12px 24px;
    border-radius: 0 0 8px 8px;
    z-index: 9999;
    font-weight: 600;
    text-decoration: none;
    transition: top var(--transition-fast);
}

.skip-link:focus {
    top: 0;
}

/* Screen reader only */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Base Styles */
html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-dark);
    color: var(--text);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 24px;
}

/* Typography */
h1, h2, h3, h4 {
    line-height: 1.3;
    font-weight: 700;
}

h2 {
    font-size: clamp(1.5rem, 4vw, 1.75rem);
    margin-bottom: 2rem;
    text-align: center;
}

h3 {
    font-size: 1.2rem;
}

a {
    color: var(--accent);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--primary-light);
}

a:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

strong {
    color: var(--text);
}

code {
    font-family: var(--font-mono);
    background: var(--bg-dark);
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.9em;
}

/* ===========================================
   Hero Section
   =========================================== */
.hero {
    text-align: center;
    padding: var(--section-padding) 24px;
    background: linear-gradient(135deg, var(--bg-dark) 0%, #1e3a5f 100%);
}

.hero-icon {
    font-size: clamp(3rem, 8vw, 4rem);
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 16px;
}

.hero h1 {
    font-size: clamp(2rem, 6vw, 3rem);
    margin-bottom: 16px;
}

.tagline {
    font-size: clamp(1.2rem, 3vw, 1.5rem);
    color: var(--accent);
    margin-bottom: 24px;
}

.description {
    font-size: clamp(1rem, 2.5vw, 1.1rem);
    color: var(--text-muted);
    margin-bottom: 32px;
    line-height: 2;
}

/* Download Button */
.btn-download {
    display: inline-block;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: white;
    padding: 16px 40px;
    border-radius: 12px;
    font-size: clamp(1rem, 2.5vw, 1.2rem);
    font-weight: 600;
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
    border: none;
    cursor: pointer;
}

.btn-download:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(37, 99, 235, 0.5);
    color: white;
}

.btn-download:focus-visible {
    outline: 3px solid var(--accent);
    outline-offset: 3px;
}

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

.btn-sub {
    display: block;
    font-size: 0.8rem;
    font-weight: 400;
    opacity: 0.85;
    margin-top: 6px;
}

/* Download Counter */
.download-count {
    margin-top: 16px;
    color: var(--text-muted);
    font-size: 0.95rem;
}

#download-counter {
    color: var(--accent);
    font-weight: 600;
    font-size: 1.1rem;
}

/* GitHub Link */
.link-github {
    display: inline-block;
    margin-top: 20px;
    color: var(--text-muted);
    font-size: 0.95rem;
    transition: color var(--transition-fast);
}

.link-github:hover {
    color: var(--accent);
}

/* ===========================================
   Features Section
   =========================================== */
.features {
    padding: var(--section-padding) 24px;
    background-color: var(--bg-section);
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 24px;
}

.feature-card {
    background: var(--bg-dark);
    padding: 32px 24px;
    border-radius: 16px;
    text-align: center;
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.3);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

.feature-card h3 {
    margin-bottom: 12px;
}

.feature-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* ===========================================
   How it Works Section
   =========================================== */
.how-it-works {
    padding: var(--section-padding) 24px;
}

.usage-table {
    max-width: 500px;
    margin: 0 auto 24px;
}

.usage-row {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
    padding: 20px;
    background: var(--bg-section);
    border-radius: 12px;
    margin-bottom: 16px;
}

.usage-key {
    font-size: 1.1rem;
    font-weight: 600;
    background: var(--bg-dark);
    padding: 12px 20px;
    border-radius: 8px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.usage-arrow {
    color: var(--accent);
    font-size: 1.5rem;
    flex-shrink: 0;
}

.usage-result {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--accent);
}

.usage-note {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* ===========================================
   Installation Section
   =========================================== */
.installation {
    padding: var(--section-padding) 24px;
    background-color: var(--bg-section);
}

.install-steps {
    list-style: none;
    max-width: 600px;
    margin: 0 auto;
}

.install-steps li {
    display: flex;
    gap: 20px;
    margin-bottom: 32px;
}

.install-steps li:last-child {
    margin-bottom: 0;
}

.step-number {
    flex-shrink: 0;
    width: 40px;
    height: 40px;
    background: var(--primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.1rem;
}

.step-content h3 {
    margin-bottom: 8px;
}

.step-content p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

.step-detail {
    font-size: 0.85rem !important;
    margin-top: 8px;
}

/* ===========================================
   Comparison Section
   =========================================== */
.comparison {
    padding: var(--section-padding) 24px;
}

.comparison-content p {
    max-width: 600px;
    margin: 0 auto 20px;
    text-align: center;
    color: var(--text-muted);
}

.comparison-table-wrapper {
    overflow-x: auto;
    margin-top: 32px;
    -webkit-overflow-scrolling: touch;
}

.comparison-table {
    width: 100%;
    max-width: 500px;
    margin: 0 auto;
    border-collapse: collapse;
    background: var(--bg-section);
    border-radius: 12px;
    overflow: hidden;
}

.comparison-table th,
.comparison-table td {
    padding: 16px 20px;
    text-align: center;
}

.comparison-table th {
    background: var(--bg-dark);
    font-weight: 600;
    color: var(--text);
}

.comparison-table th:first-child {
    text-align: left;
}

.comparison-table td:first-child {
    text-align: left;
    color: var(--text-muted);
}

.comparison-table tbody tr {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.comparison-table tbody tr:hover {
    background: rgba(255, 255, 255, 0.02);
}

.check {
    color: var(--success);
    font-weight: 700;
    font-size: 1.2rem;
}

.cross {
    color: var(--danger);
    font-size: 1.2rem;
}

/* ===========================================
   FAQ Section
   =========================================== */
.faq {
    padding: var(--section-padding) 24px;
    background-color: var(--bg-section);
}

.faq-list {
    max-width: 700px;
    margin: 0 auto;
}

.faq-item {
    background: var(--bg-dark);
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 16px;
}

.faq-item:last-child {
    margin-bottom: 0;
}

.faq-item h3 {
    color: var(--accent);
    margin-bottom: 12px;
    font-size: 1.1rem;
}

.faq-item p {
    color: var(--text-muted);
    font-size: 0.95rem;
    line-height: 1.8;
}

.faq-item a {
    color: var(--accent);
}

/* ===========================================
   Release Notes Section
   =========================================== */
.release-notes {
    padding: var(--section-padding) 24px;
}

.release-list {
    max-width: 600px;
    margin: 0 auto;
}

.release {
    background: var(--bg-section);
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 24px;
}

.release:last-child {
    margin-bottom: 0;
}

.release-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
    padding-bottom: 12px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.release-header h3 {
    color: var(--accent);
    font-size: 1.3rem;
}

.release-date {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.release-changes {
    list-style: none;
}

.release-changes li {
    position: relative;
    padding-left: 20px;
    margin-bottom: 8px;
    color: var(--text-muted);
    font-size: 0.95rem;
}

.release-changes li:last-child {
    margin-bottom: 0;
}

.release-changes li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--primary);
}

/* ===========================================
   Footer
   =========================================== */
.footer {
    padding: 48px 24px 40px;
    text-align: center;
    background-color: var(--bg-section);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-links {
    list-style: none;
    display: flex;
    justify-content: center;
    gap: 24px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--text-muted);
    font-size: 0.95rem;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: var(--accent);
}

.footer p {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 8px;
}

.footer a {
    color: var(--accent);
}

.copyright {
    margin-top: 16px;
}

.copyright small {
    color: var(--text-muted);
    font-size: 0.8rem;
}

/* ===========================================
   Responsive Design
   =========================================== */
@media (max-width: 600px) {
    .usage-row {
        flex-direction: column;
        gap: 12px;
    }

    .usage-arrow {
        transform: rotate(90deg);
    }

    .install-steps li {
        gap: 16px;
    }

    .step-number {
        width: 36px;
        height: 36px;
        font-size: 1rem;
    }

    .comparison-table th,
    .comparison-table td {
        padding: 12px;
        font-size: 0.9rem;
    }

    .footer-links {
        gap: 16px;
    }

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

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --text-muted: #b4c6dc;
    }

    .btn-download {
        border: 2px solid white;
    }

    .feature-card,
    .faq-item,
    .release {
        border: 1px solid rgba(255, 255, 255, 0.2);
    }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }

    html {
        scroll-behavior: auto;
    }
}

/* Print styles */
@media print {
    body {
        background: white;
        color: black;
    }

    .hero {
        background: none;
    }

    .btn-download,
    .skip-link,
    .footer-links {
        display: none;
    }
}