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

html {
    height: 100%;
    margin: 0;
}

body {
    line-height: 1.6;
    background-color: #f0f0f0;
    margin: 0;
    padding-left: 0;
    padding-right: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.page-container {
    display: flex;
    justify-content: center;
    padding: 20px;
    gap: 20px;
}

.toc {
    flex: 0 0 250px;
    background: linear-gradient(145deg, #ffffff, #f2f2f2);
    padding: 20px;
    border-radius: 12px;
    height: fit-content;
    position: sticky;
    top: 20px;
    box-shadow: 2px 2px 8px rgba(0, 0, 0, 0.1);
    border: 1px solid #ddd;
}

.toc-title {
    font-size: 1.2em;
    font-weight: bold;
    margin-top: 0;
    margin-bottom: 12px;
    color: #1a1f36;
    border-left: none;
    padding-left: 0;
    text-align: center;
}

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

.toc ul li {
    margin-bottom: 8px;
}

.toc ul li a {
    text-decoration: none;
    color: #444;
    padding: 4px 8px;
    display: block;
    border-radius: 6px;
    transition: all 0.2s ease;
}

.toc ul li a:hover {
    text-decoration: underline;
    color: #1a1f36;
    background-color: transparent;
}

main {
    font-family: "Hiragino Kaku Gothic ProN", "Hiragino Sans", sans-serif;
    flex: 1;
    max-width: 900px;
    background: #fff;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}

.card-link {
    display: block;
    border: 1px solid #ccc;
    border-radius: 8px;
    padding: 15px 20px;
    margin-bottom: 15px;
    text-decoration: none;
    color: #333;
    background-color: #fdfdfd;
    transition: all 0.3s ease;
}

.card-link:hover {
    border-color: #1e90ff;
    background-color: #f0f8ff;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.card-link h2 {
    margin: 0 0 0.5em 0;
    font-size: 1.2rem;
}

.card-link p {
    margin: 0;
    font-size: 0.95rem;
    color: #555;
}

.card-link.disabled {
    pointer-events: none;
    color: #999;
    background-color: #f5f5f5;
    border-color: #ddd;
}

.card-link.disabled h2 {
    color: #aaa;
}

.card-link.disabled:hover {
    border-color: #ddd;
    background-color: #f5f5f5;
    box-shadow: none;
    cursor: default;
}

.page-title {
    font-size: 1.5em;
    font-weight: 600;
    color: #1a1f36;
    margin: 0 0 16px 8px;
    letter-spacing: 0.5px;
    font-family: "Yu Mincho", "游明朝", "Hiragino Mincho ProN", "ヒラギノ明朝 ProN W3", "ＭＳ Ｐ明朝", serif;
    padding-bottom: 6px;
}

h1,
h2,
h3 {
    color: #222;
}

h1 {
    font-size: 26px;
    margin-bottom: 0.5em;
}

h2 {
    font-size: 20px;
    margin-top: 1em;
    margin-bottom: 0.2em;
    border-bottom: solid 3px #cce4ff;
    position: relative;
}

h2:after {
    position: absolute;
    content: " ";
    display: block;
    border-bottom: solid 3px #5472cd;
    bottom: -3px;
    width: 20%;
}

h3 {
    font-size: 16px;
    margin-top: 1.5em;
    margin-bottom: 0.3em;
    border-left: 4px solid #5472cd;
    padding-left: 12px;
    border-radius: 4px;
}

p {
    font-size: clamp(15px, 1vw + 10px, 15px);
    margin: 0 0;
}

ul {
    margin: 0.5em 0 0.5em 1.5em;
}

li {
    margin-bottom: 0.3em;
}

.return-link {
    display: inline-block;
    margin-bottom: 1rem;
    color: #0073aa;
    text-decoration: none;
    font-size: 0.95rem;
}

.return-link:hover {
    text-decoration: underline;
    color: #005f8c;
}

.proof-box {
    border: 2px solid #888;
    border-radius: 8px;
    padding: 1em;
    margin: 1.5em 0;
    background-color: #f9f9f9;
}

.proof-box p {
    margin: 0.5em 0;
}

.align-table {
    margin: 0 auto;
    border-collapse: collapse;
    text-align: left;
}

.align-table td {
    padding: 4px 8px;
    font-size: 16px;
}

figure {
    margin: 1em 0;
    text-align: center;
}

figure img {
    max-width: 100%;
    height: auto;
    border: 1px solid #ccc;
    border-radius: 6px;
}

figcaption {
    font-size: 0.9em;
    color: #555;
    margin-top: 0.3em;
}

.flex-images {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    gap: 10px;
    flex-wrap: wrap;
    margin: 20px 0;
}

.flex-images img {
    width: 48%;
    height: auto;
    border-radius: 6px;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);
}
mjx-container {
  font-size: 1.05em !important;
}
@media (max-width: 600px) {
    .flex-images img {
        width: 100%;
    }
}

@media (max-width: 410px) {
    .align-table td {
        font-size: 14px;
    }
}

@media (max-width: 410px) {
    main {
        padding: 14px;
    }
}

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

    .toc {
        display: none;
    }
}