/* NotesBD Tools v1.1.0 — beautiful, fast, Bangla-first calculators (no external libraries) */
.nbt-wrap{max-width:780px;margin:0 auto;font-size:17px;line-height:1.85;color:#1d2b26}
.nbt-wrap *{box-sizing:border-box}

/* ---------- tool box ---------- */
.nbt-toolbox{background:#fff;border:1px solid #e3ece7;border-radius:18px;padding:30px 28px;box-shadow:0 8px 28px rgba(0,106,78,.08);margin:26px 0;position:relative;overflow:hidden}
.nbt-toolbox:before{content:"";position:absolute;top:0;left:0;right:0;height:5px;background:linear-gradient(90deg,#006a4e,#0a8a66)}
.nbt-toolbox h3.nbt-t{margin:0 0 6px;font-size:23px;color:#0d3b2e;letter-spacing:-.2px}
.nbt-toolbox p.nbt-sub{margin:0 0 20px;color:#5a6f66;font-size:15.5px}
.nbt-grid2{display:grid;grid-template-columns:1fr 1fr;gap:14px}
@media(max-width:560px){.nbt-grid2{grid-template-columns:1fr}.nbt-toolbox{padding:22px 18px}}
.nbt-field{margin-bottom:14px}
.nbt-field label{display:block;font-weight:700;margin-bottom:7px;font-size:15px;color:#0d3b2e}
.nbt-field input[type=text],.nbt-field input[type=number],.nbt-field input[type=date],.nbt-field select{width:100%;padding:12px 14px;border:1.5px solid #cfddd6;border-radius:10px;font-size:16px;background:#fbfdfc;color:#1d2b26;box-sizing:border-box;font-family:inherit}
.nbt-field input:focus,.nbt-field select:focus{outline:none;border-color:#006a4e;box-shadow:0 0 0 3px rgba(0,106,78,.12)}
.nbt-btn{display:inline-block;background:#006a4e;color:#fff;border:none;border-radius:10px;padding:14px 36px;font-size:17px;font-weight:700;cursor:pointer;transition:background .15s,transform .1s;font-family:inherit}
.nbt-btn:hover{background:#00563f}
.nbt-btn:active{transform:scale(.98)}

/* ---------- result card ---------- */
.nbt-result{display:none;margin-top:22px;border-radius:14px;overflow:hidden;border:1px solid #cfe6d8}
.nbt-result.show{display:block;animation:nbtPop .25s ease}
@keyframes nbtPop{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}
.nbt-result-head{background:linear-gradient(135deg,#006a4e,#0a8a66);color:#fff;padding:20px 22px;text-align:center}
.nbt-result-head .nbt-big{font-size:42px;font-weight:800;line-height:1.2}
.nbt-result-head .nbt-cap{font-size:14px;opacity:.92;margin-top:4px}
.nbt-result-body{padding:18px 22px;background:#f4faf7}
.nbt-result-body table{width:100%;border-collapse:collapse;font-size:15px}
.nbt-result-body th,.nbt-result-body td{padding:9px 10px;border-bottom:1px solid #dde9e2;text-align:left}
.nbt-result-body th{color:#0d3b2e;width:45%}
.nbt-badge{display:inline-block;padding:4px 16px;border-radius:20px;font-size:13px;font-weight:700;margin-top:10px}
.nbt-badge.ok{background:#d9f2e4;color:#0b6b3f}
.nbt-badge.warn{background:#fdf0d3;color:#8a5c00}
.nbt-badge.bad{background:#fbe3e0;color:#b3261e}
.nbt-note{font-size:13.5px;color:#6b7f75;margin-top:14px;background:#f4faf7;border-radius:10px;padding:10px 14px}

/* ---------- hub ---------- */
.nbt-hub-intro{margin:6px 0 8px}
.nbt-hub-intro h2{font-size:22px;color:#0d3b2e;margin:0 0 10px}
.nbt-hub-intro p{color:#3c4f47;margin:0 0 6px}
.nbt-hub-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px;margin:22px 0 8px}
@media(max-width:560px){.nbt-hub-grid{grid-template-columns:1fr}}
.nbt-hub-card{display:block;background:#fff;border:1px solid #e3ece7;border-radius:14px;padding:22px 18px;text-decoration:none;color:inherit;transition:transform .15s,box-shadow .15s;position:relative;overflow:hidden}
.nbt-hub-card:before{content:"";position:absolute;top:0;left:0;right:0;height:4px;background:var(--nbt-accent,#006a4e);opacity:.9}
.nbt-hub-card:hover{transform:translateY(-3px);box-shadow:0 10px 26px rgba(0,106,78,.12);text-decoration:none}
.nbt-hub-ic{width:56px;height:56px;border-radius:15px;margin-bottom:12px;position:relative;box-shadow:inset 0 0 0 1px rgba(0,0,0,.04)}
.nbt-hub-ic svg{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);width:32px;height:32px;display:block}
.nbt-hub-card b{display:block;font-size:17px;color:#0d3b2e;margin-bottom:6px}
.nbt-hub-card span{font-size:14px;color:#5a6f66;line-height:1.6;display:block}
.nbt-hub-card .nbt-go{display:inline-block;margin-top:10px;font-size:14px;font-weight:700;color:#006a4e}
.nbt-hub-card .nbt-go i{font-style:normal}
.nbt-hub-card .nbt-go i{font-style:normal;transition:transform .18s}
.nbt-hub-card:hover .nbt-go i{transform:translateX(4px)}
.nbt-hub-note{margin-top:26px;background:#f4faf7;border:1px solid #e3ece7;border-radius:14px;padding:20px 24px}
.nbt-hub-note h2{font-size:19px;color:#0d3b2e;margin:0 0 10px}
.nbt-hub-note ul{margin:0;padding-left:22px;color:#3c4f47}
.nbt-hub-note li{margin-bottom:6px}

/* ---------- guide ---------- */
.nbt-guide{margin-top:36px}
.nbt-guide h2{font-size:22px;color:#0d3b2e;margin:32px 0 14px;padding-bottom:10px;border-bottom:2px solid #e3ece7;letter-spacing:-.2px}
.nbt-guide h3{font-size:18.5px;color:#0d3b2e;margin:24px 0 10px}
.nbt-guide p{margin:0 0 15px;color:#2c3e37}
.nbt-guide ul,.nbt-guide ol{margin:0 0 15px;padding-left:24px;color:#2c3e37}
.nbt-guide li{margin-bottom:9px}
.nbt-guide table{width:100%;border-collapse:collapse;margin:16px 0;font-size:15.5px;display:table}
.nbt-guide th,.nbt-guide td{border:1px solid #dde9e2;padding:10px 13px;text-align:left}
.nbt-guide th{background:#eef6f1;color:#0d3b2e;font-weight:700}
.nbt-guide tr:nth-child(even) td{background:#fafdfb}
@media(max-width:560px){.nbt-guide table{font-size:14px}.nbt-guide th,.nbt-guide td{padding:8px 9px}}
.nbt-guide .nbt-tip{background:#eef7ff;border-left:4px solid #2f7fd1;border-radius:0 10px 10px 0;padding:13px 17px;margin:18px 0;font-size:15.5px;color:#1d2b26}
.nbt-formula{text-align:center;font-size:18px;background:#eef6f1;border:1px dashed #9ec7b2;border-radius:12px;padding:16px 14px;margin:18px 0;color:#0d3b2e}

/* ---------- FAQ (robust accordion) ---------- */
.nbt-faq{margin-top:12px}
.nbt-faq details{display:block;background:#fff;border:1px solid #e3ece7;border-radius:12px;margin-bottom:12px;overflow:hidden;transition:border-color .15s,box-shadow .15s}
.nbt-faq details[open]{border-color:#9ec7b2;box-shadow:0 4px 14px rgba(0,106,78,.08)}
.nbt-faq summary{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:15px 19px;font-weight:700;cursor:pointer;color:#0d3b2e;list-style:none;font-size:16px;margin:0}
.nbt-faq summary::-webkit-details-marker{display:none}
.nbt-faq summary::marker{display:none}
.nbt-faq summary span{flex:1}
.nbt-faq summary:after{content:"+";flex:none;width:28px;height:28px;border-radius:50%;background:#eef6f1;color:#006a4e;font-weight:800;font-size:18px;line-height:28px;text-align:center;transition:transform .2s,background .2s}
.nbt-faq details[open] summary:after{content:"–";background:#006a4e;color:#fff;transform:rotate(180deg)}
.nbt-faq details>div{padding:0 19px 18px;margin:0}
.nbt-faq details p{padding:0;margin:0;color:#3c4f47;font-size:15.5px;line-height:1.75}