:root {
    --primary-color: #0066cc;
    --primary-hover: #0052a3;
    --text-color: #1a1a1a;
    --text-secondary: #666;
    --border-color: #e0e0e0;
    --bg-light: #f8f9fa;
    --bg-white: #ffffff;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --radius: 8px;
}

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

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

.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    padding: 60px 20px 40px;
}

h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text-color);
}

.subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
}

main {
    background: var(--bg-white);
    border-radius: var(--radius);
    padding: 40px;
    box-shadow: var(--shadow);
    margin-bottom: 40px;
}

section {
    margin-bottom: 48px;
}

section:last-child {
    margin-bottom: 0;
}

h2 {
    font-size: 1.75rem;
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--border-color);
}

h3 {
    font-size: 1.25rem;
    margin-bottom: 16px;
    color: var(--text-secondary);
}

h4 {
    font-size: 1.1rem;
    margin-bottom: 8px;
    color: var(--text-color);
}

.info p {
    font-size: 1.1rem;
    color: var(--text-secondary);
}

.os-selector {
    display: flex;
    gap: 8px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.os-btn {
    padding: 10px 20px;
    background: var(--bg-light);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.95rem;
    transition: all 0.2s;
    color: var(--text-color);
}

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

.os-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.releases {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.loading {
    text-align: center;
    color: var(--text-secondary);
    padding: 20px;
}

.release-item {
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 20px;
    transition: box-shadow 0.2s;
}

.release-item:hover {
    box-shadow: var(--shadow);
}

.release-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.release-version {
    font-size: 1.3rem;
    font-weight: 600;
}

.release-date {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.release-assets {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 12px;
}

.os-section {
    margin-bottom: 24px;
}

.os-section:last-child {
    margin-bottom: 0;
}

.os-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 8px;
}

.os-icon {
    font-size: 1.3rem;
}

.asset-link {
    display: flex;
    align-items: center;
    padding: 12px 16px;
    background: var(--bg-light);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    text-decoration: none;
    color: var(--text-color);
    transition: all 0.2s;
}

.asset-link:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.asset-icon {
    margin-right: 10px;
    font-size: 1.2rem;
}

.asset-info {
    flex: 1;
}

.asset-name {
    font-weight: 500;
    display: block;
    margin-bottom: 2px;
}

.asset-size {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.asset-link:hover .asset-size {
    color: rgba(255, 255, 255, 0.8);
}

.platforms {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 24px;
}

.platform {
    padding: 20px;
    background: var(--bg-light);
    border-radius: var(--radius);
}

.platform p {
    color: var(--text-secondary);
    margin-bottom: 8px;
}

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

.platform li {
    padding: 4px 0;
    color: var(--text-secondary);
}

.platform li::before {
    content: "•";
    color: var(--primary-color);
    font-weight: bold;
    display: inline-block;
    width: 1em;
    margin-left: 0;
}

footer {
    text-align: center;
    padding: 20px;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    .container {
        padding: 10px;
    }

    h1 {
        font-size: 2rem;
    }

    main {
        padding: 24px;
    }

    .release-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
    }

    .release-assets {
        grid-template-columns: 1fr;
    }

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

/* 折りたたみ機能 */
.other-releases {
    margin-top: 12px;
}

.other-title {
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 0;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 12px;
}

.other-title:not(.collapsible) {
    display: none;
}

.other-title::before {
    content: '▶';
    transition: transform 0.2s;
}

.other-title.collapsible::before {
    content: '▶';
}

.other-releases.collapsed .other-title::before {
    transform: rotate(0deg);
}

.other-releases:not(.collapsed) .other-title::before {
    transform: rotate(90deg);
}

.other-releases.collapsed .release-assets {
    display: none;
}

.other-releases:not(.collapsed) .release-assets {
    display: grid;
}

/* リリースなしメッセージ */
.no-releases {
    text-align: center;
    padding: 40px 20px;
    color: var(--text-secondary);
    font-size: 1.1rem;
}