:root{
    --tb-green:#16a34a;
    --tb-orange:#f97316;
    --tb-black:#111827;
    --tb-gray:#e5e7eb;
    --tb-bg:#f8fafc;
}

.tb-tyre-search{
    font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
    background: var(--tb-bg);
    border: 1px solid var(--tb-gray);
    border-radius: 10px;
    padding: 18px;
    box-shadow: 0 8px 20px rgba(0,0,0,.05);
    color: var(--tb-black);
}
.tb-tyre-search__header{
    display:flex; align-items:center; gap:.6rem;
    font-size:1.05rem; font-weight:700;
    color: var(--tb-black);
    border-bottom:2px solid var(--tb-green);
    padding-bottom:.6rem; margin-bottom:1rem;
}
.tb-icon{font-size:1.2rem}

/* 9 columnas: 2 + 1 + 1 + 1 + 1 + 1 + 2 */
.tb-grid{
    display:grid;
    grid-template-columns: repeat(9, minmax(0,1fr));
    gap:12px;
    align-items:end;
}
.tb-span-2{grid-column: span 2}

.tb-field{display:flex; flex-direction:column; gap:6px}
.tb-field label{
    font-size:.8rem; font-weight:700; color:#374151; letter-spacing:.02em;
}

/* Select con flecha invertida */
.tb-select{
    appearance:none;
    padding:.65rem 2.4rem .65rem .9rem;
    border:1px solid var(--tb-gray);
    border-radius:8px;
    background:#fff;
    color:#111;
    line-height:1.2;
    transition: border-color .2s, box-shadow .2s;
    background-image:
        url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='14' height='14' viewBox='0 0 24 24'%3E%3Cpath fill='%23f97316' d='M7 10l5 5 5-5z'/%3E%3C/svg%3E");
    background-repeat:no-repeat;
    background-position: right .8rem center;
    background-size: 14px 14px;
}
.tb-select:focus{
    outline:none; border-color: var(--tb-green);
    box-shadow: 0 0 0 3px rgba(22,163,74,.15);
}

/* Checkboxes centrados y simples */
.tb-flags{
    display:flex; flex-wrap:wrap; gap:10px 16px;
    justify-content:center;
    margin-top:14px;
}
.tb-check{
    display:inline-flex; align-items:center; gap:.5rem;
    font-size:.95rem; color:#1f2937;
    cursor:pointer; user-select:none;
}
.tb-check input{
    width:18px; height:18px;
    accent-color: var(--tb-green);
}

.tb-actions{
    display:flex; justify-content:center; margin-top:16px;
}
.tb-btn{
    background: linear-gradient(90deg, var(--tb-green), var(--tb-orange));
    color:#fff; border:0; border-radius:10px;
    padding:.9rem 2.2rem; font-weight:800; letter-spacing:.04em;
    text-transform:uppercase;
    box-shadow: 0 6px 14px rgba(249,115,22,.25);
    cursor:pointer; transition: transform .08s ease, box-shadow .2s ease;
}
.tb-btn:hover{box-shadow: 0 10px 22px rgba(22,163,74,.25)}
.tb-btn:active{transform: translateY(1px)}

/* Responsive */
@media (max-width: 1100px){
    .tb-grid{grid-template-columns: repeat(3, minmax(0,1fr))}
    .tb-span-2{grid-column: span 3}
}
@media (max-width: 640px){
    .tb-grid{grid-template-columns: 1fr}
    .tb-span-2{grid-column: span 1}
    .tb-actions{justify-content:stretch}
    .tb-btn{width:100%}
}