/* ============================================================
   DES SIMULATOR — style.css
   Design: Terminal/cipher aesthetic, IBM Plex fonts,
   dark theme with amber accent — inspired by old crypto hardware
   ============================================================ */

:root {
  --bg:        #0d0e11;
  --bg2:       #13151a;
  --bg3:       #1a1d24;
  --bg4:       #22262f;
  --border:    #2a2f3a;
  --border2:   #363d4a;
  --text:      #d4d8e2;
  --text2:     #717a8a;
  --text3:     #4a5163;
  --amber:     #f5a623;
  --amber2:    #ffca6e;
  --green:     #39d98a;
  --red:       #f05d5d;
  --blue:      #4d9de0;
  --purple:    #b97aff;
  --bit0:      #1e2430;
  --bit1:      #1d3a2a;
  --bit0t:     #4a5163;
  --bit1t:     #39d98a;
  --radius:    6px;
  --mono:      'IBM Plex Mono', monospace;
  --sans:      'IBM Plex Sans', sans-serif;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  font-size: 14px;
  line-height: 1.6;
}

/* ── HEADER ─────────────────────────────────── */
header {
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  padding: 0 2rem;
  height: 60px;
  display: flex; align-items: center;
  position: sticky; top: 0; z-index: 100;
}
.header-inner {
  width: 100%; max-width: 1280px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
}
.logo { display: flex; align-items: baseline; gap: 0.5rem; }
.logo-des {
  font-family: var(--mono);
  font-size: 1.4rem; font-weight: 600;
  color: var(--amber);
  letter-spacing: 0.05em;
  text-shadow: 0 0 20px rgba(245,166,35,0.4);
}
.logo-sub { font-family: var(--mono); font-size: 0.75rem; color: var(--text2); letter-spacing: 0.2em; text-transform: uppercase; }
.header-badge {
  font-family: var(--mono); font-size: 0.7rem;
  color: var(--text3); letter-spacing: 0.1em;
  padding: 0.25rem 0.75rem;
  border: 1px solid var(--border2); border-radius: 100px;
}

/* ── MAIN LAYOUT ─────────────────────────────── */
main {
  max-width: 1280px; margin: 0 auto;
  padding: 2rem;
}

/* ── SECTION LABEL ───────────────────────────── */
.section-label {
  font-family: var(--mono); font-size: 0.65rem;
  color: var(--amber); letter-spacing: 0.25em;
  text-transform: uppercase; margin-bottom: 1.25rem;
}

/* ── INPUT SECTION ────────────────────────────── */
.section-input {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 2rem;
  margin-bottom: 1.5rem;
}

/* Mode toggle */
.mode-row { display: flex; gap: 0.5rem; margin-bottom: 1.5rem; }
.mode-btn {
  display: flex; align-items: center; gap: 0.4rem;
  padding: 0.55rem 1.4rem;
  border-radius: var(--radius);
  border: 1px solid var(--border2);
  background: var(--bg3); color: var(--text2);
  font-family: var(--sans); font-size: 0.85rem; font-weight: 500;
  cursor: pointer; transition: all 0.18s;
}
.mode-btn:hover { border-color: var(--amber); color: var(--amber); }
.mode-btn.active {
  background: rgba(245,166,35,0.12);
  border-color: var(--amber); color: var(--amber);
  box-shadow: 0 0 0 1px rgba(245,166,35,0.2);
}
.mode-icon { font-size: 1rem; }

/* Format toggle */
.format-row { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 1.25rem; }
.format-label { font-size: 0.8rem; color: var(--text2); white-space: nowrap; }
.format-toggle { display: flex; border: 1px solid var(--border2); border-radius: var(--radius); overflow: hidden; }
.fmt-btn {
  padding: 0.3rem 0.9rem;
  background: transparent; border: none;
  color: var(--text2); font-size: 0.78rem; font-family: var(--mono);
  cursor: pointer; transition: all 0.15s;
}
.fmt-btn:hover { color: var(--text); background: var(--bg3); }
.fmt-btn.active { background: var(--bg4); color: var(--amber); }

/* Input grid */
.input-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 1rem;
  margin-bottom: 1.25rem;
}
@media (max-width: 700px) { .input-grid { grid-template-columns: 1fr; } }

.field-group { display: flex; flex-direction: column; gap: 0.4rem; }
.field-label {
  font-size: 0.78rem; color: var(--text2); font-weight: 500;
  display: flex; align-items: center; gap: 0.5rem;
}
.bit-badge {
  font-family: var(--mono); font-size: 0.65rem;
  padding: 0.1rem 0.5rem; border-radius: 100px;
  background: var(--bg4); border: 1px solid var(--border2);
  color: var(--text3);
  transition: all 0.2s;
}
.bit-badge.valid { border-color: var(--green); color: var(--green); background: rgba(57,217,138,0.08); }
.bit-badge.invalid { border-color: var(--red); color: var(--red); background: rgba(240,93,93,0.08); }

.field-input {
  background: var(--bg); border: 1px solid var(--border2);
  border-radius: var(--radius); color: var(--text);
  font-family: var(--mono); font-size: 0.9rem;
  padding: 0.65rem 0.85rem;
  outline: none; transition: border-color 0.18s, box-shadow 0.18s;
  letter-spacing: 0.05em;
}
.field-input:focus { border-color: var(--amber); box-shadow: 0 0 0 2px rgba(245,166,35,0.12); }
.field-input.valid { border-color: var(--green); }
.field-input.invalid { border-color: var(--red); }

.field-hint { font-size: 0.72rem; color: var(--text3); min-height: 1rem; }
.field-hint.ok { color: var(--green); }
.field-hint.err { color: var(--red); }

/* Preset */
.preset-row { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 1.5rem; flex-wrap: wrap; }
.preset-btn {
  padding: 0.3rem 0.8rem;
  border: 1px solid var(--border2); border-radius: var(--radius);
  background: var(--bg3); color: var(--text2);
  font-size: 0.75rem; font-family: var(--mono);
  cursor: pointer; transition: all 0.15s;
}
.preset-btn:hover { border-color: var(--blue); color: var(--blue); }

/* Actions */
.action-row { display: flex; align-items: center; gap: 0.75rem; }
.btn-run {
  display: flex; align-items: center; gap: 0.5rem;
  padding: 0.7rem 1.8rem;
  background: var(--amber); color: #000;
  border: none; border-radius: var(--radius);
  font-family: var(--sans); font-size: 0.9rem; font-weight: 600;
  cursor: pointer; transition: all 0.18s;
}
.btn-run:hover { background: var(--amber2); transform: translateY(-1px); box-shadow: 0 4px 16px rgba(245,166,35,0.35); }
.btn-run:active { transform: translateY(0); }
.btn-arrow { font-size: 1rem; }
.btn-reset {
  padding: 0.7rem 1.2rem;
  background: transparent; border: 1px solid var(--border2);
  border-radius: var(--radius); color: var(--text2);
  font-size: 0.85rem; cursor: pointer; transition: all 0.15s;
}
.btn-reset:hover { border-color: var(--red); color: var(--red); }

.error-msg {
  margin-top: 0.75rem; font-size: 0.8rem; color: var(--red);
  font-family: var(--mono); min-height: 1.2rem;
}

/* ── RESULT BANNER ────────────────────────────── */
.section-result {
  background: linear-gradient(135deg, var(--bg2) 0%, rgba(245,166,35,0.06) 100%);
  border: 1px solid rgba(245,166,35,0.25);
  border-radius: 10px; padding: 1.5rem 2rem;
  margin-bottom: 1.5rem;
}
.section-result.hidden { display: none; }

.result-inner {}
.result-row {
  display: flex; align-items: center; gap: 1.5rem;
  margin-bottom: 1rem; flex-wrap: wrap;
}
.result-item { flex: 1; min-width: 200px; }
.result-item.highlight { flex: 1.5; }
.result-label { font-size: 0.72rem; color: var(--text2); text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: 0.3rem; }
.result-val { font-family: var(--mono); font-size: 1rem; color: var(--text); word-break: break-all; }
.result-val.large { font-size: 1.4rem; color: var(--amber); letter-spacing: 0.08em; }
.result-arrow { font-size: 1.5rem; color: var(--text3); }
.result-bins { display: flex; flex-direction: column; gap: 0.35rem; padding-top: 0.75rem; border-top: 1px solid var(--border); margin-bottom: 0.75rem; }
.bin-row { display: flex; align-items: baseline; gap: 0.75rem; flex-wrap: wrap; }
.bin-label { font-size: 0.72rem; color: var(--text2); white-space: nowrap; }
.mono { font-family: var(--mono); }
.small { font-size: 0.78rem; color: var(--text2); word-break: break-all; }

.roundtrip-row { display: flex; }
.btn-roundtrip {
  padding: 0.4rem 1rem;
  border: 1px solid var(--border2); border-radius: var(--radius);
  background: transparent; color: var(--text2);
  font-size: 0.78rem; cursor: pointer; transition: all 0.15s;
}
.btn-roundtrip:hover { border-color: var(--blue); color: var(--blue); }

/* ── STEPS NAV ───────────────────────────────── */
.steps-nav {
  display: flex; gap: 0.25rem; flex-wrap: wrap;
  margin-bottom: 1.5rem;
  padding: 0.35rem;
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: 8px;
}
.steps-nav.hidden { display: none; }
.nav-btn {
  padding: 0.5rem 1.1rem; border-radius: 5px;
  border: none; background: transparent; color: var(--text2);
  font-size: 0.8rem; font-weight: 500; cursor: pointer; transition: all 0.15s;
}
.nav-btn:hover { color: var(--text); background: var(--bg3); }
.nav-btn.active { background: var(--bg4); color: var(--amber); }

/* ── TAB PANELS ──────────────────────────────── */
.tab-panel {
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: 10px; padding: 2rem;
  margin-bottom: 1.5rem;
}
.tab-panel.hidden { display: none; }

.panel-header { margin-bottom: 1.75rem; }
.panel-title { font-size: 1.05rem; font-weight: 600; margin-bottom: 0.4rem; }
.panel-desc { font-size: 0.82rem; color: var(--text2); line-height: 1.6; }

/* ── STEP BLOCKS ─────────────────────────────── */
.step-block {
  margin-bottom: 1.5rem; padding: 1.25rem;
  background: var(--bg3); border: 1px solid var(--border);
  border-radius: var(--radius);
}
.step-title { font-size: 0.82rem; font-weight: 600; color: var(--amber); margin-bottom: 0.6rem; }
.step-desc { font-size: 0.78rem; color: var(--text2); margin-bottom: 0.75rem; }
.mt { margin-top: 0.85rem; }

/* ── BIT DISPLAY ─────────────────────────────── */
.bit-display-wrap {}
.bit-label { font-size: 0.72rem; color: var(--text3); margin-bottom: 0.3rem; font-family: var(--mono); }

.bit-row {
  display: flex; flex-wrap: wrap; gap: 2px;
  font-family: var(--mono);
}

.bit {
  width: 18px; height: 22px;
  display: inline-flex; align-items: center; justify-content: center;
  font-size: 0.68rem; border-radius: 3px;
  transition: background 0.15s;
}
.bit.b0 { background: var(--bit0); color: var(--bit0t); }
.bit.b1 { background: var(--bit1); color: var(--bit1t); }
.bit.highlight { background: rgba(245,166,35,0.2); color: var(--amber); }

.bit-row.small .bit { width: 16px; height: 18px; font-size: 0.62rem; }

/* ── CD SPLIT ────────────────────────────────── */
.cd-split { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
@media (max-width: 700px) { .cd-split { grid-template-columns: 1fr; } }
.cd-half {}
.cd-label { font-size: 0.75rem; font-weight: 600; color: var(--purple); margin-bottom: 0.4rem; }
.mono-val { font-family: var(--mono); font-size: 0.7rem; color: var(--text2); margin-top: 0.3rem; }

/* ── KEY SCHEDULE TABLE ──────────────────────── */
.ks-table-wrap { overflow-x: auto; }
.ks-table {
  width: 100%; border-collapse: collapse;
  font-family: var(--mono); font-size: 0.72rem;
}
.ks-table th {
  padding: 0.5rem 0.75rem; text-align: left;
  background: var(--bg4); color: var(--text2);
  border-bottom: 1px solid var(--border2);
  font-weight: 600; white-space: nowrap;
}
.ks-table td {
  padding: 0.45rem 0.75rem;
  border-bottom: 1px solid var(--border);
  color: var(--text); vertical-align: middle;
  word-break: break-all;
}
.ks-table tr:hover td { background: rgba(255,255,255,0.02); }
.ks-table .round-num { color: var(--amber); font-weight: 600; text-align: center; }
.ks-table .ls-val { color: var(--blue); text-align: center; }
.ks-table .subkey-cell { color: var(--green); font-size: 0.68rem; }
.ks-table .hex-cell { color: var(--amber2); }

/* ── ROUND DETAIL ────────────────────────────── */
.round-filter { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 1.5rem; flex-wrap: wrap; }
.round-btns { display: flex; flex-wrap: wrap; gap: 0.25rem; }
.round-num-btn {
  width: 36px; height: 30px; border-radius: 4px;
  border: 1px solid var(--border2); background: var(--bg3);
  color: var(--text2); font-family: var(--mono); font-size: 0.72rem;
  cursor: pointer; transition: all 0.15s;
}
.round-num-btn:hover { border-color: var(--amber); color: var(--amber); }
.round-num-btn.active { background: var(--amber); color: #000; border-color: var(--amber); font-weight: 600; }

.round-card {
  background: var(--bg3); border: 1px solid var(--border);
  border-radius: 8px; padding: 1.5rem;
}
.round-card-header {
  display: flex; align-items: center; gap: 1rem;
  margin-bottom: 1.25rem; padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border);
}
.round-num-big {
  font-family: var(--mono); font-size: 1.8rem; font-weight: 600;
  color: var(--amber); min-width: 60px;
}
.round-meta { font-size: 0.78rem; color: var(--text2); }
.round-meta strong { color: var(--text); }

.round-steps { display: flex; flex-direction: column; gap: 0.75rem; }

.round-step {
  padding: 0.85rem 1rem;
  background: var(--bg4); border-radius: 5px;
  border-left: 3px solid var(--border2);
}
.round-step.e-exp { border-left-color: var(--blue); }
.round-step.xor   { border-left-color: var(--purple); }
.round-step.sbox  { border-left-color: var(--green); }
.round-step.pperm { border-left-color: var(--amber); }
.round-step.swap  { border-left-color: var(--text2); }

.rs-title { font-size: 0.7rem; font-weight: 600; color: var(--text2); text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: 0.4rem; }
.rs-title.blue   { color: var(--blue); }
.rs-title.purple { color: var(--purple); }
.rs-title.green  { color: var(--green); }
.rs-title.amber  { color: var(--amber); }

.rs-val { font-family: var(--mono); font-size: 0.75rem; color: var(--text); word-break: break-all; line-height: 1.7; }
.rs-sub { font-size: 0.7rem; color: var(--text2); margin-top: 0.2rem; }

/* ── SBOX DETAIL ─────────────────────────────── */
.sbox-round-select { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 1.5rem; }
.sel-input {
  background: var(--bg3); border: 1px solid var(--border2);
  border-radius: var(--radius); color: var(--text);
  font-family: var(--mono); font-size: 0.82rem;
  padding: 0.4rem 0.75rem; outline: none;
}
.sel-input:focus { border-color: var(--amber); }

.sbox-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 0.75rem; margin-bottom: 1.5rem; }
@media (max-width: 900px) { .sbox-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 500px) { .sbox-grid { grid-template-columns: 1fr; } }

.sbox-item {
  background: var(--bg4); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 0.85rem;
}
.sbox-num { font-size: 0.7rem; font-weight: 700; color: var(--green); margin-bottom: 0.5rem; }
.sbox-row { display: flex; gap: 0.4rem; flex-wrap: wrap; margin-bottom: 0.4rem; }
.sbox-tag {
  font-family: var(--mono); font-size: 0.68rem;
  padding: 0.15rem 0.4rem; border-radius: 3px;
}
.sbox-tag.in  { background: rgba(77,157,224,0.15); color: var(--blue); }
.sbox-tag.row { background: rgba(185,122,255,0.15); color: var(--purple); }
.sbox-tag.col { background: rgba(57,217,138,0.15); color: var(--green); }
.sbox-tag.out { background: rgba(245,166,35,0.15); color: var(--amber); font-weight: 600; }
.sbox-formula { font-family: var(--mono); font-size: 0.7rem; color: var(--text2); margin-top: 0.35rem; }

.sbox-static-wrap { overflow-x: auto; margin-bottom: 1.5rem; }
.sbox-static-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; }
@media (max-width: 900px) { .sbox-static-grid { grid-template-columns: repeat(2, 1fr); } }

.sbox-ref {
  background: var(--bg4); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 0.75rem;
}
.sbox-ref-title { font-size: 0.72rem; font-weight: 700; color: var(--green); margin-bottom: 0.5rem; }
.sbox-ref-table { border-collapse: collapse; width: 100%; }
.sbox-ref-table td, .sbox-ref-table th {
  width: 22px; height: 20px;
  text-align: center; padding: 0.1rem;
  font-family: var(--mono); font-size: 0.58rem;
  color: var(--text2);
}
.sbox-ref-table th { color: var(--text3); border-bottom: 1px solid var(--border); }
.sbox-ref-table td.highlighted { background: rgba(245,166,35,0.2); color: var(--amber); font-weight: 700; }

/* ── FINAL OUTPUT ────────────────────────────── */
.highlight-row .bit.b1 { background: rgba(245,166,35,0.25); color: var(--amber); }
.highlight-row .bit.b0 { background: rgba(245,166,35,0.06); color: rgba(245,166,35,0.5); }
.final-hex-row { display: flex; align-items: center; gap: 0.75rem; margin-top: 0.75rem; }
.final-hex { font-size: 1.6rem; color: var(--amber); letter-spacing: 0.12em; }

/* ── FOOTER ──────────────────────────────────── */
footer {
  border-top: 1px solid var(--border);
  padding: 1.25rem 2rem;
  margin-top: 3rem;
}
.footer-inner {
  max-width: 1280px; margin: 0 auto;
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 0.5rem;
  font-size: 0.72rem; color: var(--text3); font-family: var(--mono);
}

/* ── UTILITIES ───────────────────────────────── */
.hidden { display: none !important; }

/* XOR display in round */
.xor-display {
  display: grid; grid-template-columns: 1fr auto 1fr auto 1fr;
  align-items: center; gap: 0.5rem; font-family: var(--mono); font-size: 0.72rem;
  overflow-x: auto;
}
.xor-op { color: var(--purple); font-weight: 700; font-size: 1rem; }
.xor-val { word-break: break-all; line-height: 1.7; color: var(--text); }
.xor-val.result { color: var(--green); }
.xor-val.key { color: var(--blue); }

/* Scrollbar */
::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: var(--bg2); }
::-webkit-scrollbar-thumb { background: var(--border2); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--amber); }