/* 全体にボックスサイズを適用 */
* {
    box-sizing: border-box;
}

body {
    font-family: 'Poppins', 'Segoe UI', 'Helvetica Neue', sans-serif;
    background: linear-gradient(135deg, #ffe6f0, #e6f7ff);
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 100vh;
}

header {
    width: 100%;
    background: linear-gradient(90deg, #ffb6c1, #ffa6d1, #ffe6f0);
    padding: 15px;
    text-align: center;
    font-size: 1.3em;
    font-weight: bold;
    color: #fff;
    letter-spacing: 1px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    border-radius: 0 0 12px 12px;
}

.container {
    background: #fff;
    border-radius: 20px;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
    padding: 30px;
    max-width: 400px;
    width: 90%;
    text-align: center;
    animation: fadeIn 1s ease;
    margin: 40px auto;
}

.page-intro {
    font-family: 'Poppins', 'Segoe UI', 'Helvetica Neue', sans-serif;
    font-size: 1.1rem;
    font-weight: 800;
    text-align: center;
    color: #fff;
    /* 文字色を白に */
    text-shadow:
        0 0 5px #ff9fcf,
        0 0 10px #ff9fcf,
        0 0 20px #ff69b4,
        0 0 40px #ff69b4,
        0 0 60px #ff69b4;
    line-height: 1.8em;
    margin: 50px 20px;
    animation: neonGlow 1.5s ease-in-out infinite alternate, fadeInDown 1s ease;
}

@keyframes neonGlow {
    0% {
        text-shadow:
            0 0 3px #ff9fcf,
            0 0 5px #ff9fcf,
            0 0 10px #ff69b4,
            0 0 20px #ff69b4,
            0 0 30px #ff69b4;
    }

    100% {
        text-shadow:
            0 0 5px #ff9fcf,
            0 0 10px #ff9fcf,
            0 0 20px #ff69b4,
            0 0 40px #ff69b4,
            0 0 60px #ff69b4;
    }
}

@keyframes fadeInDown {
    0% {
        opacity: 0;
        transform: translateY(-20px);
    }

    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

h2 {
    margin-bottom: 25px;
    font-size: 1.1em;
    color: #ff408c;
    text-shadow: 0 0 8px #ffb6c1;
    font-weight: 600;
}

h3 {
    margin-top: 0px;
    margin-bottom: 15px;
    font-size: 1.3em;
    color: #ff85c1;
    text-shadow: 0 0 5px #ffb6c1;
    font-weight: 500;
}

h4 {
    margin-bottom: 15px;
    font-size: 0.8em;
    color: hsl(0, 0%, 45%);
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.08);
    font-weight: 500;
}

h5 {
    font-size: 1rem;
    color: #ff69b4;
    text-shadow: 0 0 6px #ffc0cb;
    font-weight: 800;
    margin-top: 50px;
    margin-bottom: 0px;
}

.color-btn {
    display: inline-block;
    width: 70px;
    height: 70px;
    margin: 10px;
    border-radius: 50%;
    border: 3px solid #fff;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.15);
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

.color-btn:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 14px rgba(0, 0, 0, 0.25);
}

.custom-section {
    margin-top: 0px;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
}

#customCircle {
    width: 90px;
    height: 90px;
    border-radius: 50%;
    border: 3px solid #fff;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.15);
    cursor: default;
    transition: transform 0.2s, box-shadow 0.2s;
    margin-bottom: 15px;
}

#colorPickerWrapper {
    width: 100%;
    display: flex;
    justify-content: center;
    margin: 10px 0;
}

button.launch {
    margin-top: 15px;
    margin-bottom: 40px;
    padding: 12px 25px;
    font-size: 1em;
    background: linear-gradient(135deg, #ff69b4, #ff85c1);
    color: white;
    border: none;
    border-radius: 30px;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    transition: background 0.3s, transform 0.2s;
}

button.launch:hover {
    background: linear-gradient(135deg, #ff408c, #ff6fa1);
    transform: scale(1.05);
}

footer {
    width: 100%;
    background: linear-gradient(90deg, #ffe6f0, #ffb6c1);
    padding: 15px 0;
    text-align: center;
    font-size: 0.9em;
    color: #ffffff;
    box-shadow: 0 -2px 8px rgba(0, 0, 0, 0.1);
    border-radius: 12px 12px 0 0;
    margin-top: 40px;
}

.support-links {
    margin-top: 10px;
}

.support-links a {
    display: inline-flex;
    align-items: center;
    gap: 6px;

    padding: 8px 18px;
    font-size: 0.85em;
    font-weight: 500;

    color: #ff5fa2;
    text-decoration: none;

    background: rgba(255, 255, 255, 0.35);
    backdrop-filter: blur(6px);

    border-radius: 999px;
    border: 1px solid rgba(255, 255, 255, 0.6);

    box-shadow:
        0 2px 6px rgba(255, 105, 180, 0.15),
        inset 0 0 0 rgba(255, 255, 255, 0.0);

    transition:
        transform 0.2s ease,
        box-shadow 0.2s ease,
        background 0.2s ease;
}

.support-links a:hover {
    transform: translateY(-1px);
    background: rgba(255, 255, 255, 0.55);
    box-shadow:
        0 4px 10px rgba(255, 105, 180, 0.25),
        inset 0 0 8px rgba(255, 255, 255, 0.6);
}

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

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

@media (max-width: 420px) {
    .container {
        width: 85%;
        padding: 20px;
    }
}