.instruments-wrapper {
    max-width: 880px;
    width: 100%;
    margin: 0 auto;
}

.instruments-wrapper .accordion button {
    cursor: default;
}

/* accordion container */
.accordion {
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
}

/* each card (accordion item) */
.accordion-item {
    background: #ffffff;
    border-radius: 1.5rem;
    box-shadow: 0 12px 24px -12px rgba(0, 0, 0, 0.2), 0 2px 6px rgba(0, 0, 0, 0.05);
    transition: all 0.2s ease;
    overflow: hidden;
    border: 1px solid rgba(70, 130, 180, 0.15);
}

.accordion-item:hover {
    box-shadow: 0 20px 28px -14px rgba(0, 0, 0, 0.25);
}

/* button header */
.accordion-header {
    width: 100%;
    background: #ffffff;
    border: none;
    padding: 1.2rem 1.8rem;
    text-align: left;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    font-weight: 600;
    font-size: 1.3rem;
    font-family: inherit;
    transition: background 0.2s;
    color: #1f3e53;
    border-bottom: 2px solid transparent;
}

.accordion-header:focus-visible {
    outline: 3px solid #2c7ab1;
    outline-offset: -2px;
    border-radius: 1.5rem;
}

.accordion-item.active .accordion-header {
    background: #f9fcff;
    border-bottom-color: #cbdde9;
}

.instrument-title {
    display: flex;
    align-items: baseline;
    gap: 0.6rem;
    flex-wrap: wrap;
}

.instrument-name {
    font-size: 1.2rem;
    font-weight: 500;
    background: linear-gradient(120deg, #1f5e8e, #143e5a);
    background-clip: text;
    -webkit-background-clip: text;
    color: transparent;
}

.instrument-model {
    font-size: 0.9rem;
    font-weight: 500;
    background: #eef2f7;
    padding: 0.2rem 0.7rem;
    border-radius: 30px;
    color: #2c6285;
}

.arrow-icon {
    font-size: 1.8rem;
    font-weight: 300;
    transition: transform 0.3s cubic-bezier(0.2, 0.9, 0.4, 1.1);
    color: #2c7a9e;
    line-height: 1;
}

.accordion-item.active .arrow-icon {
    transform: rotate(180deg);
}

/* content panel */
.accordion-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease-out, padding 0.2s;
    background: #ffffff;
    padding: 0 1.8rem;
}

.accordion-item.active .accordion-content {
    max-height: 800px;   /* enough for all specs */
    padding: 0.4rem 1.8rem 1.5rem 1.8rem;
}

/* specs grid */
.specs-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 0.8rem 1.2rem;
    margin-top: 0.8rem;
}

.spec-item {
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    border-bottom: 1px dashed #e2eaf1;
    padding: 0.5rem 0;
    font-size: 0.94rem;
}

.spec-label {
    font-weight: 700;
    min-width: 130px;
    color: #1c597b;
    background: #f0f6fc;
    padding: 0.2rem 0.5rem;
    border-radius: 12px;
    font-size: 0.82rem;
    letter-spacing: 0.3px;
    text-transform: uppercase;
    margin-right: 0.8rem;
}

.spec-value {
    color: #1e2f3c;
    font-weight: 500;
    word-break: break-word;
    flex: 1;
}

.spec-value.empty-dash {
    color: #8aa0ae;
    font-style: italic;
}

.badge-bsl {
    background: #e3f0f5;
    display: inline-block;
    padding: 0.2rem 0.7rem;
    border-radius: 40px;
    font-size: 0.75rem;
    font-weight: 600;
    color: #126e8c;
}

hr {
    margin: 0.8rem 0 0.2rem;
    border: 0;
    height: 1px;
    background: linear-gradient(to right, #cbdde9, transparent);
}

/* responsive */
@media (max-width: 580px) {
    body {
        padding: 1rem;
    }
    .accordion-header {
        padding: 1rem 1.2rem;
    }
    .instrument-name {
        font-size: 1.2rem;
    }
    .specs-grid {
        grid-template-columns: 1fr;
    }
    .spec-label {
        min-width: 110px;
    }
    .accordion-item.active .accordion-content {
        padding: 0rem 1.2rem 1.2rem 1.2rem;
    }
}

/* additional micro-interactions */
.accordion-header:hover {
    background: #f6fafd;
}

.btn {
    background: white;
    color: #105079;
    border: none;
    padding: 1rem 2.5rem;
    border-radius: 3rem;
    font-weight: 700;
    font-size: 1.1rem;
    cursor: pointer;
    transition: 0.2s;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.15);
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
}

.btn i {
    font-size: 1.2rem;
}

.btn:hover {
    background: #ebf7ff;
    transform: scale(1.02);
    box-shadow: 0 16px 24px rgba(0, 42, 66, 0.3);
}