:root{
    --layout-width: 1320px;
}
/* ---------- NAV / DARK TOGGLE ---------- */

.nav-btn,
button{

    font-family:'JetBrains Mono', monospace;
    font-size:13px;
    padding:9px 16px;
    border:1px solid var(--paper-line);
    border-radius:6px;
    background:var(--paper-cell);
    color:var(--ink);
    cursor:pointer;
    text-decoration:none;
    display:inline-flex;
    align-items:center;
    gap:6px;
    transition:border-color .2s ease, color .2s ease, background-color .2s ease;

}

.nav-btn:hover,
button:hover{ border-color:var(--vermilion); color:var(--vermilion); background:var(--paper-cell); }

.nav-btn:focus-visible,
button:focus-visible{ outline:2px solid var(--vermilion); outline-offset:2px; }

.shuffle-btn{

    margin-left:0;

}

.field-theme{

    margin-left:auto;

}

/* ---------- GRID ---------- */

.grid.table-mode{

    grid-template-columns:repeat(5,1fr) !important;
    max-width:var(--layout-width);

}

.grid.yoon-mode{

    grid-template-columns:repeat(3,1fr) !important;
    max-width:520px;

}

.card.blank{

    visibility:hidden;
    pointer-events:none;

}

.card{

    position:relative;
    height:70px;
    perspective:1000px;
    cursor:pointer;

}

.inner{

    width:100%;
    height:100%;
    position:relative;
    transition:transform .5s cubic-bezier(.4,.1,.2,1);
    transform-style:preserve-3d;

}

.card.flipped .inner{

    transform:rotateY(180deg);

}

@media (prefers-reduced-motion:reduce){
    .inner{ transition:none; }
}

.front,
.back{

    position:absolute;
    inset:0;
    border-radius:var(--radius);
    display:flex;
    justify-content:center;
    align-items:center;
    text-align:center;
    padding:4px;
    line-height:1.2;
    word-break:break-word;
    backface-visibility:hidden;
    border:1px solid var(--paper-line);
    box-shadow:var(--shadow);

}

.front{

    background:var(--paper-cell);
    color:var(--ink);
    font-weight:700;
    font-size:30px;

}

@media only screen and (max-width: 500px) {
    .front{ font-size:24px; }
    button{ justify-content:center; }
    .field-theme{ margin-left:0; }
    .multiselect-panel{ left:0; right:0; }
}

.back{

    background:var(--indigo);
    color:#F7F2E7;
    font-family:'JetBrains Mono', monospace;
    font-size:15px;
    font-weight:500;
    transform:rotateY(180deg);
    border-color:var(--indigo-deep);

}

.card:hover .front,
.card:hover .back{

    border-color:var(--vermilion);

}

/* ---------- DARK MODE ---------- */

body.dark{

    background-image:
        linear-gradient(var(--paper-line) 1px, transparent 1px),
        linear-gradient(90deg, var(--paper-line) 1px, transparent 1px);
    background-size:34px 34px;

}

body.dark .subtitle{

    color:var(--ink-soft);

}

.field{

    display:flex;
    flex-direction:column;
    gap:4px;
    position:relative;
    width: 19.1%;

}

/* ---------- FRONT / BACK ---------- */

.abacus{
    display:flex;
    align-items:center;
    gap:10px;
    cursor:pointer;
    user-select:none;
    padding:10px 14px;
    border:1px solid var(--paper-line);
    border-radius:6px;
    background:var(--paper-cell);
    transition:border-color .2s ease;
}

.abacus:hover{ border-color:var(--vermilion); }
.abacus:focus-visible{ outline:2px solid var(--vermilion); outline-offset:2px; }
.abacus-label{
    font-family:'JetBrains Mono',monospace;
    font-size:11.5px;
    color:var(--ink-soft);
    transition:color .2s ease,font-weight .2s ease;
}
.abacus-label.active{ color:var(--vermilion); font-weight:600; }
.rod{ position:relative; width:52px; height:3px; background:var(--ink-soft); border-radius:2px; }
.bead{ position:absolute; top:50%; left:0; width:20px; height:20px; border-radius:50%; background:var(--vermilion); box-shadow:0 1px 4px rgba(0,0,0,.25); transform:translate(0,-50%); transition:transform .28s cubic-bezier(.5,-.3,.5,1.3); }
.abacus.right .bead{ transform:translate(32px,-50%); }
.direction-filter-field .abacus{ min-width:154px; justify-content:center; }

@media (prefers-reduced-motion:reduce){ .bead{ transition:none; } }