.sd-diff {
    padding: 2px 8px;
    border-radius: 9999px;
    font-size: 12px;
    border: 1px solid transparent;
    display: inline-flex; /* 用 flex */
    align-items: center; /* 垂直居中 */
    justify-content: center; /* 水平居中 */
    line-height: 1.4;
    width: 50px;
}

/* —— None —— */
.sd-diff--none {
    color: #4b5563;
    background: #f9fafb;
    border-color: #e5e7eb;
} /* gray-600 / 50 / 200 */

/* —— Easy —— */
.sd-diff--easy-minus {
    color: #047857;
    background: #ecfdf5;
    border-color: #a7f3d0;
} /* emerald-700 / 50 / 200 */
.sd-diff--easy-plus {
    color: #064e3b;
    background: #d1fae5;
    border-color: #34d399;
} /* emerald-900 / 100 / 400 */

/* —— Medium —— */
.sd-diff--medium-minus {
    color: #92400e;
    background: #fffbeb;
    border-color: #fcd34d;
} /* amber-800 / 50 / 300 */
.sd-diff--medium-plus {
    color: #78350f;
    background: #fef3c7;
    border-color: #f59e0b;
} /* amber-900 / 100 / 500 */

/* —— Hard —— */
.sd-diff--hard-minus {
    color: #991b1b;
    background: #fef2f2;
    border-color: #fca5a5;
} /* red-800 / 50 / 300 */
.sd-diff--hard-plus {
    color: #7f1d1d;
    background: #fee2e2;
    border-color: #ef4444;
} /* red-900 / 100 / 500 */

/* 兼容旧三档命名（可选：保留原样或映射到“minus”/“plus”中的任一档） */
.sd-diff--easy {
    color: #065f46;
    background: #ecfdf5;
    border-color: #a7f3d0;
}
.sd-diff--medium {
    color: #78350f;
    background: #fffbeb;
    border-color: #fcd34d;
}
.sd-diff--hard {
    color: #7f1d1d;
    background: #fef2f2;
    border-color: #fecaca;
}

/* // 或把整个 a 去掉 */
.col--difficulty a[href="javascript:;"] {
    display: none;
}