.converter-card {
    border-radius: 16px;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.08);
    border: none;
    transition: all 0.3s ease;
}
.converter-card:hover {
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.12);
}
.unit-input-group {
    display: flex;
    align-items: center;
    margin-bottom: 12px;
    border-radius: 10px;
    background: #fafbff;
    padding: 4px 8px 4px 16px;
    border: 2px solid #eef1f7;
    transition: all 0.2s ease;
}
.unit-input-group:focus-within {
    border-color: #4e73df;
    box-shadow: 0 0 0 4px rgba(78, 115, 223, 0.12);
    background: #fff;
}
.unit-input-group .unit-label {
    font-weight: 600;
    color: #2c3e6b;
    min-width: 70px;
    font-size: 1rem;
    letter-spacing: 0.3px;
    flex-shrink: 0;
}
.unit-input-group .unit-input {
    border: none;
    background: transparent;
    padding: 10px 12px;
    font-size: 1.05rem;
    font-weight: 500;
    width: 100%;
    outline: none;
    text-align: right;
    font-family: 'Courier New', monospace;
    flex: 1;
    min-width: 0;
}
.unit-input-group .unit-input::placeholder {
    color: #b0b8c8;
    font-weight: 400;
    font-size: 0.9rem;
}
.unit-input-group .unit-input:focus {
    background: transparent;
    box-shadow: none;
}
.unit-input-group.active-unit {
    border-color: #4e73df;
    background: #f0f4ff;
}
.unit-convert-btn {
    border-radius: 8px;
    padding: 6px 14px;
    font-size: 0.85rem;
    font-weight: 600;
    background: #4e73df;
    color: #fff;
    border: none;
    transition: all 0.2s ease;
    flex-shrink: 0;
    margin-left: 6px;
    white-space: nowrap;
}
.unit-convert-btn:hover {
    background: #3a5fc8;
    transform: scale(1.04);
    box-shadow: 0 2px 8px rgba(78, 115, 223, 0.35);
}
.unit-convert-btn:active {
    transform: scale(0.96);
}
.convert-btn-main {
    padding: 12px 48px;
    border-radius: 10px;
    font-weight: 600;
    font-size: 1.05rem;
    background: linear-gradient(135deg, #4e73df 0%, #224abe 100%);
    border: none;
    color: #fff;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(78, 115, 223, 0.35);
}
.convert-btn-main:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(78, 115, 223, 0.45);
    background: linear-gradient(135deg, #3a5fc8 0%, #1a3a8a 100%);
}
.convert-btn-main:active {
    transform: translateY(0px);
}
.quick-preset {
    display: inline-block;
    padding: 5px 14px;
    border-radius: 20px;
    background: #f1f4fb;
    color: #2c3e6b;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    border: 1px solid transparent;
    margin: 3px 4px;
}
.quick-preset:hover {
    background: #e2e8f7;
    border-color: #4e73df;
    transform: scale(1.04);
}
.quick-preset.active {
    background: #4e73df;
    color: #fff;
    border-color: #4e73df;
}
.history-item {
    display: flex;
    justify-content: space-between;
    padding: 8px 12px;
    border-bottom: 1px solid #f0f2f7;
    font-size: 0.92rem;
    cursor: pointer;
    transition: background 0.15s ease;
    border-radius: 6px;
}
.history-item:hover {
    background: #f5f7fd;
}
.history-item:last-child {
    border-bottom: none;
}
.history-value {
    font-weight: 600;
    color: #2c3e6b;
}
.history-detail {
    color: #6c7a9a;
}
.clear-history {
    color: #a0aec0;
    font-size: 0.8rem;
    cursor: pointer;
    transition: color 0.2s ease;
    text-decoration: none;
}
.clear-history:hover {
    color: #e74a3b;
    text-decoration: underline;
}
.reference-table td {
    padding: 6px 8px;
    font-size: 0.9rem;
    border-bottom: 1px solid #f0f2f7;
}
.reference-table tr:last-child td {
    border-bottom: none;
}
.reference-table td:first-child {
    font-weight: 500;
    color: #2c3e6b;
}
.reference-table td:last-child {
    color: #5a6a8a;
}
.detail-bar {
    background: #f8faff;
    border-radius: 10px;
    padding: 10px 16px;
    border-left: 4px solid #4e73df;
    font-size: 0.95rem;
    color: #2c3e6b;
    margin-top: 8px;
}
@media (max-width: 768px) {
    .unit-input-group .unit-label {
        min-width: 55px;
        font-size: 0.9rem;
    }
    .unit-input-group .unit-input {
        font-size: 0.95rem;
        padding: 8px 8px;
    }
    .unit-convert-btn {
        padding: 4px 10px;
        font-size: 0.75rem;
    }
    .convert-btn-main {
        width: 100%;
        padding: 14px;
    }
    .unit-input-group {
        padding: 2px 6px 2px 12px;
    }
    .detail-bar {
        font-size: 0.85rem;
    }
}