@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;600;700&family=Inter:wght@400;500;600;700;800&display=swap');

:root {
  --bg: #f4f6fb;
  --white: #ffffff;
  --surface: #f0f2fa;
  --border: #dde2f0;
  --border2: #c5cce8;
  --accent: #4f46e5;
  --alight: #eef0ff;
  --green: #059669;
  --amber: #b45309;
  --blue: #0369a1;
  --red: #dc2626;
  --tmid: #4b5563;
  --tdim: #9ca3af;
  --text: #1e1b4b;
  --mono: 'JetBrains Mono', monospace;
  --sans: 'Inter', sans-serif;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
}

.header {
  background: linear-gradient(135deg, #4338ca, #6366f1);
  padding: 34px 20px 28px;
  text-align: center;
}

.header h1 {
  color: #fff;
  font-size: clamp(20px, 4vw, 32px);
  font-weight: 800;
  margin-bottom: 6px;
}

.header p {
  color: rgba(255, 255, 255, 0.75);
  font-size: 13px;
}

.wrap {
  max-width: 980px;
  margin: 0 auto;
  padding: 26px 16px 60px;
}

.card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 24px;
  margin-bottom: 18px;
  box-shadow: 0 1px 4px rgba(79, 70, 229, 0.06);
}

.card-lbl {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 16px;
}

.igrid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin-bottom: 18px;
}

@media (max-width: 560px) {
  .igrid {
    grid-template-columns: 1fr;
  }
}

.field label {
  display: block;
  font-size: 12px;
  font-weight: 600;
  color: var(--tmid);
  margin-bottom: 6px;
}

.field input {
  width: 100%;
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: 8px;
  padding: 10px 13px;
  color: var(--text);
  font-family: var(--mono);
  font-size: 18px;
  font-weight: 600;
  letter-spacing: 5px;
  outline: none;
}

.field input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.field input.err {
  border-color: var(--red);
}

.fhint {
  font-size: 11px;
  color: var(--tdim);
  margin-top: 4px;
}

.ferr {
  display: none;
  font-size: 11px;
  color: var(--red);
  margin-top: 4px;
}

.mode-row {
  margin-bottom: 18px;
}

.ml {
  font-size: 12px;
  font-weight: 600;
  color: var(--tmid);
  margin-bottom: 7px;
}

.mtog {
  display: inline-flex;
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: 8px;
  padding: 3px;
  gap: 3px;
}

.mbtn {
  padding: 7px 20px;
  border: none;
  background: none;
  color: var(--tmid);
  font-family: var(--sans);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  border-radius: 6px;
}

.mbtn.active {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 2px 8px rgba(79, 70, 229, 0.25);
}

.brow {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.btn {
  padding: 10px 24px;
  border-radius: 8px;
  border: none;
  font-family: var(--sans);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
}

.btn-p {
  background: var(--accent);
  color: #fff;
}

.btn-s {
  background: var(--surface);
  color: var(--tmid);
  border: 1.5px solid var(--border);
}

#rbox {
  display: none;
}

.rhero {
  background: linear-gradient(135deg, var(--alight), #e0e7ff);
  border: 1.5px solid #c7d2fe;
  border-radius: 10px;
  padding: 22px;
  text-align: center;
}

.rlbl {
  font-size: 11px;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 1px;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.rbits {
  display: flex;
  justify-content: center;
  gap: 6px;
  flex-wrap: wrap;
  margin-bottom: 12px;
}

.rbit {
  width: 42px;
  height: 42px;
  background: #fff;
  border: 1.5px solid #c7d2fe;
  border-radius: 7px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--mono);
  font-size: 22px;
  font-weight: 700;
}

.rbit.one {
  color: var(--accent);
  background: var(--alight);
}

.rbit.zero {
  color: var(--tdim);
}

.rstr {
  font-family: var(--mono);
  font-size: 24px;
  font-weight: 800;
  color: var(--accent);
  letter-spacing: 5px;
}

.togbtn {
  width: 100%;
  margin-top: 16px;
  padding: 12px 18px;
  background: var(--surface);
  border: 1.5px dashed var(--border2);
  border-radius: 8px;
  color: var(--tmid);
  font-family: var(--sans);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
}

#sol {
  display: none;
  margin-top: 18px;
}

.sec {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px;
  margin-bottom: 12px;
}

.stitle {
  font-size: 14px;
  font-weight: 800;
  color: var(--accent);
  margin-bottom: 14px;
  padding-bottom: 9px;
  border-bottom: 1px solid var(--border);
}

.table-wrap {
  overflow-x: auto;
  margin-bottom: 12px;
}

.tbl {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
  font-size: 13px;
  margin-bottom: 10px;
}

.tbl th,
.tbl td {
  border: 1px solid var(--border2);
  padding: 8px 10px;
  text-align: center;
}

.tbl th {
  background: var(--alight);
  color: var(--accent);
  font-weight: 700;
}

.tbl td:first-child {
  text-align: left;
  font-weight: 700;
  color: var(--tmid);
  background: var(--surface);
}

.bitline {
  font-family: var(--mono);
  font-weight: 700;
  letter-spacing: 2px;
  color: var(--accent);
}

.info {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  margin: 8px 0;
  font-size: 13px;
}

.info b {
  font-family: var(--mono);
  color: var(--accent);
}

.final-box {
  background: linear-gradient(135deg, var(--alight), #e0e7ff);
  border: 1.5px solid #c7d2fe;
  border-radius: 10px;
  padding: 16px;
  text-align: center;
  font-size: 15px;
  font-weight: 700;
}

.final-box div {
  margin: 6px 0;
}

.footer {
  text-align: center;
  padding: 18px 0 24px;
  font-size: 12px;
  color: var(--tdim);
  border-top: 1px solid var(--border);
}

/* ===== UI FIX: CENTERED FORM ACTION AREA ===== */

.mode-row {
  text-align: center;
  margin-top: 8px;
  margin-bottom: 18px;
}

.mode-row .ml {
  text-align: center;
  font-size: 13px;
  font-weight: 700;
  color: var(--tmid);
  margin-bottom: 10px;
}

.mtog {
  display: inline-grid;
  grid-template-columns: 1fr 1fr;
  width: min(360px, 100%);
  margin: 0 auto;
}

.mbtn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  min-height: 42px;
}

.brow {
  justify-content: center;
  margin-top: 10px;
}

.btn {
  min-width: 150px;
  min-height: 46px;
}

.card {
  max-width: 980px;
  margin-left: auto;
  margin-right: auto;
}

/* ===== SOLUTION DETAIL STYLE ===== */

#sol {
  max-width: 980px;
  margin-left: auto;
  margin-right: auto;
}

.sec {
  background: #f3f5fc;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
  margin-bottom: 16px;
}

.stitle {
  font-size: 15px;
  font-weight: 800;
  color: var(--accent);
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 10px;
}

.snum {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  flex-shrink: 0;
}

.fpill {
  display: inline-block;
  background: var(--alight);
  border: 1px solid #c7d2fe;
  border-radius: 7px;
  padding: 6px 12px;
  font-family: var(--mono);
  font-size: 13px;
  color: var(--accent);
  font-weight: 700;
  margin-bottom: 12px;
}

.tw {
  overflow-x: auto;
  margin: 10px 0 12px;
}

.ntbl {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--mono);
  font-size: 13px;
  background: #fff;
}

.ntbl th,
.ntbl td {
  border: 1px solid var(--border2);
  padding: 9px 12px;
  text-align: center;
  white-space: nowrap;
}

.ntbl th {
  color: var(--tdim);
  font-weight: 700;
  background: #fff;
}

.ntbl td.rh {
  text-align: left;
  font-family: var(--sans);
  font-weight: 700;
  color: var(--tmid);
  background: #eef0f8;
  min-width: 190px;
}

.ntbl td.b1,
.ntbl td.o1 {
  color: var(--accent);
  font-weight: 800;
}

.ntbl td.b0,
.ntbl td.o0 {
  color: var(--tdim);
  font-weight: 700;
}

.ntbl td.o1,
.ntbl td.o0 {
  background: #eef0ff;
}

.il {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 14px;
  margin-top: 10px;
  font-family: var(--mono);
  font-size: 13px;
}

.lb {
  color: var(--tdim);
  font-family: var(--sans);
  font-weight: 700;
}

.vl {
  font-family: var(--mono);
  font-weight: 800;
  letter-spacing: 2px;
}

.vc { color: var(--accent); }
.vg { color: var(--green); }
.va { color: var(--amber); }
.vb { color: var(--blue); }

.dv {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 18px 0 12px;
}

.dv::before,
.dv::after {
  content: "";
  flex: 1;
  border-top: 1px solid var(--border);
}

.dv span {
  color: var(--tdim);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.8px;
  text-transform: uppercase;
}

.xbox {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 9px;
  padding: 14px 18px;
  margin: 12px 0;
  font-family: var(--mono);
  font-size: 13px;
}

.xl {
  line-height: 2;
}

.xsep {
  border-top: 1.5px solid var(--border2);
  margin: 5px 0;
}

.spair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 12px;
}

@media (max-width: 700px) {
  .spair {
    grid-template-columns: 1fr;
  }
}

.sc {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 9px;
  padding: 12px;
}

.sc-title {
  font-size: 12px;
  line-height: 1.5;
  color: var(--tmid);
  margin-bottom: 10px;
}

.stbl {
  border-collapse: collapse;
  width: 100%;
  font-family: var(--mono);
  font-size: 13px;
}

.stbl th,
.stbl td {
  border: 1px solid var(--border);
  padding: 7px 9px;
  text-align: center;
}

.stbl th {
  background: var(--surface);
  color: var(--tdim);
  font-size: 11px;
}

.stbl td.hl {
  background: #ddd6fe;
  color: var(--accent);
  font-weight: 800;
}

.fbox {
  background: linear-gradient(135deg, var(--alight), #e0e7ff);
  border: 1.5px solid #c7d2fe;
  border-radius: 10px;
  padding: 18px;
  margin-top: 14px;
}

.frow {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 10px;
}

.flb {
  min-width: 90px;
  color: var(--tdim);
  font-size: 13px;
  font-weight: 800;
}

.fch {
  background: #fff;
  border: 1px solid #c7d2fe;
  border-radius: 7px;
  padding: 6px 14px;
  font-family: var(--mono);
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 2px;
}

.fck { color: var(--amber); }
.fcc { color: var(--accent); }