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

/* ベースフォント・カラー設定 */
:root {

    --primary-color: #666666;

    --secondary-color: #808080;

    --accent-color: #000000;

    --mouth-color: #4d4d4d;

    --hand-color: #a6a6a6;

    --human-hand-color: #ffe0b5;

    --point-color: #626262;



    --background-color: #F5F5F5;

    --text-color: #1a1a1a;

    --text-light: #666666;

    --card-background: #FFFFFF;

    --border-color: #CCCCCC;

    --hover-color: #F0F0F0;

    --link-color: #4d4d4d;

    --link-hover: #333333;



    --font-family: 'Hiragino Sans', 'ヒラギノ角ゴシック', 'Hiragino Kaku Gothic ProN', 'Noto Sans JP', 'メイリオ', 'Meiryo', sans-serif;
    --font-size-h1: clamp(2rem, 5vw, 3rem);
    --font-size-h2: clamp(1.5rem, 4vw, 2rem);
    --font-size-body: clamp(1rem, 2.5vw, 1.125rem);


    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;


    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;


    --shadow-sm: 0 1px 3px rgba(102, 102, 102, 0.15);
    --shadow-md: 0 4px 6px rgba(102, 102, 102, 0.15);
    --shadow-lg: 0 10px 15px rgba(102, 102, 102, 0.15);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-body);
    line-height: 1.7;
    color: var(--text-color);
    background-color: var(--background-color);
    background-image:
        radial-gradient(circle at 20% 80%, rgba(102, 102, 102, 0.03) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(102, 102, 102, 0.03) 0%, transparent 50%),
        radial-gradient(circle at 50% 50%, rgba(128, 128, 128, 0.02) 0%, transparent 70%);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: var(--spacing-lg) var(--spacing-md);
}


body>* {
    width: 100%;
    max-width: 800px;
}

h1 {
    font-size: var(--font-size-h1);
    font-weight: 700;
    color: var(--primary-color);
    text-align: center;
    margin-bottom: var(--spacing-md);
    position: relative;
    text-shadow: 1px 1px 2px rgba(102, 102, 102, 0.1);
}

h1::after {
    display: block;
    font-size: 2rem;
    margin-top: var(--spacing-xs);
    opacity: 0.8;
    filter: hue-rotate(0deg) saturate(0.7);
}

p {
    text-align: center;
    color: var(--text-light);
    margin-bottom: var(--spacing-xl);
    font-size: 1.1rem;
}

label {
    display: block;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--accent-color);
    margin: var(--spacing-xl) 0 var(--spacing-md) 0;
    padding-bottom: var(--spacing-xs);
    border-bottom: 2px solid var(--primary-color);
    position: relative;
}

label::before {
    content: '';
    position: absolute;
    left: 0;
    bottom: -2px;
    width: 40px;
    height: 2px;
    background-color: var(--point-color);
}

ul {
    list-style: none;
    margin-bottom: var(--spacing-xl);
    display: grid;
    gap: var(--spacing-md);
}

ul a {
    display: block;
    text-decoration: none;
    color: var(--text-color);
    background-color: var(--card-background);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-md) var(--spacing-lg);
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
    position: relative;
    overflow: hidden;
    font-weight: 500;
}

ul a::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: linear-gradient(to bottom, var(--primary-color), var(--point-color));
    transition: width 0.3s ease;
}

ul a:hover {
    background-color: var(--hover-color);
    border-color: var(--primary-color);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
    color: var(--mouth-color);
}

ul a:hover::before {
    width: 8px;
    background: linear-gradient(to bottom, var(--mouth-color), var(--primary-color));
}

ul a[href*="Train-Speak"]::after {
    content: '🚂';
    position: absolute;
    right: var(--spacing-md);
    top: 50%;
    transform: translateY(-50%);
    font-size: 1.5rem;
    opacity: 0.7;
    transition: opacity 0.3s ease;
    filter: hue-rotate(0deg) saturate(0.8);
}

ul a[href*="Train-Speak"]:hover::after {
    opacity: 1;
    filter: hue-rotate(10deg) saturate(1);
}

ul a[href^="https://youtube.com"]::after {
    content: '📺';
    position: absolute;
    right: var(--spacing-md);
    top: 50%;
    transform: translateY(-50%);
    font-size: 1.5rem;
    opacity: 0.7;
    transition: opacity 0.3s ease;
}

ul a[href^="https://x.com"]::after,
ul a[href^="https://twitter.com"]::after {
    content: '🐦';
    position: absolute;
    right: var(--spacing-md);
    top: 50%;
    transform: translateY(-50%);
    font-size: 1.5rem;
    opacity: 0.7;
    transition: opacity 0.3s ease;
}

ul a[href^="https://"]::after {
    opacity: 1;
}

ul a:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
    background-color: var(--hover-color);
}

@media (max-width: 768px) {
    body {
        padding: var(--spacing-md) var(--spacing-sm);
    }

    ul a {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    ul a::after {
        right: var(--spacing-sm);
        font-size: 1.25rem;
    }
}

@media (min-width: 600px) {
    ul {
        grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    }
}



@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes floatAnimation {

    0%,
    100% {
        transform: translateY(0px);
    }

    50% {
        transform: translateY(-5px);
    }
}

body>* {
    animation: fadeInUp 0.6s ease-out;
}

body>*:nth-child(2) {
    animation-delay: 0.1s;
}

body>*:nth-child(3) {
    animation-delay: 0.2s;
}

body>*:nth-child(4) {
    animation-delay: 0.3s;
}

body>*:nth-child(5) {
    animation-delay: 0.4s;
}

h1::after {
    animation: floatAnimation 3s ease-in-out infinite;
    animation-delay: 1s;
}

@media print {
    body {
        background: white;
        color: black;
    }

    ul a {
        border: 1px solid var(--primary-color);
        background: white;
    }

    ul a::after {
        display: none;
    }

    h1::after {
        animation: none;
    }
}

::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--background-color);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--mouth-color);
}