/* ── 计算器专题页 ── */

/* 计算器外框 */
.calc-wrapper {
    max-width: 380px;
    margin: 0 auto;
    background: #f8f9fb;
    border: 1px solid #e8eaf0;
    border-radius: 12px;
    padding: 1.2rem;
}

/* 显示屏 */
.calc-display {
    background: #1a1a2e;
    border-radius: 8px;
    padding: 1rem 1.2rem;
    margin-bottom: 1rem;
    min-height: 80px;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    overflow: hidden;
}

.calc-expr {
    color: #8888aa;
    font-size: 0.85rem;
    text-align: right;
    min-height: 1.2em;
    font-family: 'Fira Code', monospace;
    word-break: break-all;
}

.calc-screen {
    color: #fff;
    font-size: 2.2rem;
    font-weight: 600;
    text-align: right;
    font-family: 'Fira Code', monospace;
    line-height: 1.2;
    word-break: break-all;
}

/* 按键网格 */
.calc-keys {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
}

.calc-key {
    padding: 0.85rem;
    border: none;
    border-radius: 8px;
    font-size: 1.15rem;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.15s, transform 0.1s;
    font-family: inherit;
    user-select: none;
}

.calc-key:active {
    transform: scale(0.95);
}

.calc-key.num {
    background: #fff;
    color: #333;
    border: 1px solid #e8eaf0;
}

.calc-key.num:hover {
    background: #f0f0f0;
}

.calc-key.func {
    background: #e8eaf0;
    color: #555;
}

.calc-key.func:hover {
    background: #d8dae0;
}

.calc-key.op {
    background: #2563eb;
    color: #fff;
}

.calc-key.op:hover {
    background: #1d4ed8;
}

.calc-key.eq {
    background: #059669;
    color: #fff;
}

.calc-key.eq:hover {
    background: #047857;
}

.calc-key.zero {
    grid-column: span 2;
}

/* ── Mobile ── */
@media (max-width: 640px) {
    .calc-wrapper {
        max-width: 100%;
    }

    .calc-screen {
        font-size: 1.8rem;
    }

    .calc-key {
        padding: 0.75rem;
        font-size: 1.05rem;
    }
}