/* =========================
   ChemStudy 共通フッター
========================= */

.cs-footer {
    width: 100%;
    margin-top: 26px;
    padding: 20px 18px 16px;
    color: #cbd5e1;
    background:
        radial-gradient(circle at top left, rgba(14, 165, 233, 0.14), transparent 34%),
        linear-gradient(135deg, rgba(2, 6, 23, 0.96), rgba(15, 23, 42, 0.96));
    border-top: 1px solid rgba(148, 163, 184, 0.20);
}

.cs-footer-inner {
    width: min(1100px, 100%);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 22px;
}

.cs-footer-brand {
    min-width: 250px;
}

.cs-footer-logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
}

.cs-footer-logo-mark {
    width: 40px;
    height: 40px;
    flex-shrink: 0;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    background:
        radial-gradient(circle at 28% 25%, rgba(255, 255, 255, 0.86) 0 10%, transparent 11%),
        linear-gradient(135deg, #7dd3fc, #38bdf8 48%, #22c55e);
    border: 1px solid rgba(255, 255, 255, 0.55);
    box-shadow: 0 12px 26px rgba(56, 189, 248, 0.18);
}

.cs-footer-logo-mark svg {
    width: 24px;
    height: 24px;
    stroke: #082f49;
    fill: none;
    stroke-width: 1.9;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.cs-footer-logo-text {
    line-height: 1.05;
}

.cs-footer-logo-main {
    margin: 0;
    color: #f8fafc;
    font-size: 23px;
    font-weight: 950;
    letter-spacing: -0.045em;
}

.cs-footer-logo-main .chem {
    color: #e0f2fe;
}

.cs-footer-logo-main .study {
    background: linear-gradient(135deg, #7dd3fc, #22c55e);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.cs-footer-logo-sub {
    margin-top: 5px;
    color: #93c5fd;
    font-size: 9.5px;
    font-weight: 850;
    letter-spacing: 0.16em;
}

.cs-footer-copy {
    margin: 8px 0 0;
    color: #94a3b8;
    font-size: 12px;
    line-height: 1.6;
}

.cs-footer-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-end;
    align-items: center;
    gap: 8px 16px;
}

.cs-footer-links a {
    color: #cbd5e1;
    text-decoration: none;
    font-size: 12.5px;
    font-weight: 600;
    transition: color 0.18s ease, opacity 0.18s ease;
}

.cs-footer-links a:hover {
    color: #67e8f9;
}

.cs-footer-bottom {
    width: min(1100px, 100%);
    margin: 16px auto 0;
    padding-top: 12px;
    border-top: 1px solid rgba(148, 163, 184, 0.14);
    text-align: center;
}

.cs-footer-bottom p {
    margin: 0;
    color: #64748b;
    font-size: 12px;
}

@media (max-width: 720px) {
    .cs-footer {
        margin-top: 28px;
        padding: 24px 16px 20px;
    }

    .cs-footer-inner {
        flex-direction: column;
        align-items: center;
        text-align: center;
        gap: 18px;
    }

    .cs-footer-brand {
        min-width: 0;
    }

    .cs-footer-links {
        justify-content: center;
        gap: 12px 16px;
    }

    .cs-footer-links a {
        font-size: 12px;
    }
}

.cs-footer-social-link{
    display:inline-flex;
    align-items:center;
    justify-content:center;
    gap:7px;

    padding:6px 10px;
    border-radius:999px;

    background:rgba(15, 23, 42, 0.75);
    border:1px solid rgba(148, 163, 184, 0.28);

    color:#f8fafc;
    text-decoration:none;
    font-size:12.5px;
    font-weight:800;
    line-height:1;

    vertical-align:middle;

    transition:color 0.18s ease,
               background 0.18s ease,
               border-color 0.18s ease,
               transform 0.18s ease;
}

.cs-footer-social-link:hover{
    color:#ffffff;
    background:rgba(30, 41, 59, 0.95);
    border-color:rgba(125, 211, 252, 0.45);
    transform:translateY(-1px);
}

.cs-footer-social-icon{
    width:18px;
    height:18px;
    display:inline-flex;
    align-items:center;
    justify-content:center;
    flex-shrink:0;
    line-height:1;
}

.cs-footer-social-icon img{
    width:15px;
    height:15px;
    display:block;
    object-fit:contain;
    transform:translateY(-0.5px);
}

.cs-footer-social-link > span:last-child{
    display:inline-flex;
    align-items:center;
    line-height:1;
}