/* ---------- NAV / DARK TOGGLE ---------- */

.nav-btn,
.theme-btn{
    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;
}
.nav-btn{margin-left:auto;}
.nav-btn:hover,.theme-btn:hover{border-color:var(--vermilion);color:var(--vermilion);}
.nav-btn:focus-visible,.theme-btn:focus-visible{outline:2px solid var(--vermilion);outline-offset:2px;}

/* ---------- GRID / CARDS ---------- */
.card{
    position:relative;
    height:148px;
    perspective:1000px;
    cursor:pointer;
    box-sizing:border-box;
    border:1px solid var(--paper-line);
    border-radius:var(--radius);
    box-shadow:var(--shadow);
    overflow:hidden;
    transition:border-color .2s ease, box-shadow .2s ease;
}
.card:hover{border-color:var(--vermilion);}
.inner{
    width:100%;
    height:100%;
    position:relative;
    box-sizing:border-box;
    transition:transform .5s cubic-bezier(.4,.1,.2,1);
    transform-style:preserve-3d;
    padding-top:0 !important;
}
.card.flipped .inner{transform:rotateY(180deg);}
@media (prefers-reduced-motion:reduce){.inner{transition:none;}}

.front,.back{
    position:absolute;
    inset:0;
    border-radius:0;
    display:flex;
    justify-content:center;
    align-items:center;
    text-align:center;
    padding:58px 28px 24px;
    line-height:1.35;
    word-break:break-word;
    overflow:hidden;
    backface-visibility:hidden;
    border:0;
    box-shadow:none;
}
.front{
    background:var(--paper-cell);
    color:var(--ink);
    font-family:'JetBrains Mono',monospace;
    font-size:19px;
    font-weight:600;
}
.back{
    background:var(--indigo);
    color:#F7F2E7;
    font-family:'Shippori Mincho',serif;
    font-size:22px;
    font-weight:700;
    transform:rotateY(180deg);
}
.card.milestone .front::after,.card.milestone .back::after{
    content:"";
    position:absolute;
    top:10px;
    right:10px;
    width:6px;
    height:6px;
    border-radius:50%;
    background:var(--vermilion);
}

/* ---------- TIME / DATE CARD CONTENT ---------- */
.card .front,.card .back{text-align:center;}
.card .front{display:flex;align-items:center;justify-content:center;}
.card .back{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:5px;}
.card .back .romaji,.card .back .english,.card .back .bangla{display:block;}
.card .back .romaji{font-family:'JetBrains Mono',monospace;font-size:20px;line-height:1.25;}
.card .back .english{font-family:'JetBrains Mono',monospace;font-size:14px;font-weight:500;line-height:1.25;opacity:.9;}
.card .back .bangla{font-size:15px;line-height:1.25;}

/* ---------- FOOTNOTE ---------- */
.footnote{
    max-width:980px;
    margin:26px auto 0;
    font-family:'JetBrains Mono',monospace;
    font-size:11px;
    color:var(--ink-soft);
    display:flex;
    align-items:center;
    gap:8px;
}
.footnote .dot{width:6px;height:6px;border-radius:50%;background:var(--vermilion);flex-shrink:0;}

@media (max-width:520px){
    .kanji-mark{font-size:42px;}
    h1{font-size:22px;}
    .nav-btn{margin-left:0;}
    .card{height:128px;}
    .front,.back{padding:50px 18px 18px;}
    .front{font-size:16px;}
    .back{font-size:19px;}
    .card .back .romaji{font-size:18px;}
    .card .back .english{font-size:12px;}
    .card .back .bangla{font-size:14px;}
}

.field{display:flex;flex-direction:column;gap:4px;position:relative;width:24.1%;}

/* ---------- 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;}}
.count-display{max-width:var(--layout-width);margin:0 auto 20px;text-align:center!important;}