/* ============================================================
   DES Simulator — Stylesheet
   Palette: Navy deep (#0F1B2D), Teal accent (#00C2A8), 
            Off-white bg (#F0F4F8), Gold highlight (#F5A623)
   ============================================================ */

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

:root {
  --navy:    #0F1B2D;
  --navy-mid:#1A2D45;
  --teal:    #00C2A8;
  --teal-dim:#00A08A;
  --gold:    #F5A623;
  --bg:      #F0F4F8;
  --bg-card: #FFFFFF;
  --text:    #1A1F2E;
  --muted:   #6B7A8D;
  --border:  #DDE3EC;
  --radius:  10px;
  --shadow:  0 2px 12px rgba(15,27,45,.08);
}

body {
  font-family: 'Segoe UI', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-width: 1280px;
}

/* HEADER */
.site-header {
  background: var(--navy);
  padding: 48px 0 40px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.site-header::before {
  content: '';
  position: absolute; inset: 0;
  background: repeating-linear-gradient(
    45deg,
    transparent, transparent 20px,
    rgba(0,194,168,.04) 20px, rgba(0,194,168,.04) 21px
  );
}
.header-inner { position: relative; z-index: 1; }
.header-badge {
  display: inline-block;
  background: var(--teal);
  color: var(--navy);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 2px;
  padding: 4px 14px;
  border-radius: 20px;
  margin-bottom: 16px;
}
.site-header h1 {
  color: #fff;
  font-size: 48px;
  font-weight: 800;
  letter-spacing: -1px;
}
.accent { color: var(--teal); }
.header-sub {
  color: rgba(255,255,255,.55);
  font-size: 16px;
  margin-top: 8px;
}

/* CONTAINER */
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 40px 32px 80px;
  display: flex;
  flex-direction: column;
  gap: 28px;
}

/* CARD */
.card {
  background: var(--bg-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 32px 36px;
  border: 1px solid var(--border);
}
.card-title {
  font-size: 20px;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  gap: 12px;
}
.step-num {
  background: var(--navy);
  color: var(--teal);
  font-size: 13px;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 6px;
  letter-spacing: 1px;
}

/* INPUT GRID */
.input-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}
.mt-16 { margin-top: 16px; }

.field-group { display: flex; flex-direction: column; gap: 6px; }
.field-group label {
  font-size: 13px;
  font-weight: 600;
  color: var(--navy);
}
.hint { color: var(--muted); font-weight: 400; }

.field-group input,
.field-group select {
  border: 1.5px solid var(--border);
  border-radius: 8px;
  padding: 10px 14px;
  font-family: 'Cascadia Code', 'Consolas', monospace;
  font-size: 14px;
  color: var(--text);
  background: #FAFBFC;
  transition: border-color .2s, box-shadow .2s;
  outline: none;
}
.field-group input:focus,
.field-group select:focus {
  border-color: var(--teal);
  box-shadow: 0 0 0 3px rgba(0,194,168,.15);
}
.field-info {
  font-size: 12px;
  color: var(--muted);
  min-height: 16px;
}

/* TOGGLE */
.toggle-row { display: flex; gap: 8px; }
.toggle-btn {
  padding: 8px 20px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  background: transparent;
  font-size: 13px;
  font-weight: 600;
  color: var(--muted);
  cursor: pointer;
  transition: all .2s;
}
.toggle-btn.active {
  background: var(--navy);
  color: var(--teal);
  border-color: var(--navy);
}

/* BUTTONS */
.btn-row { display: flex; gap: 12px; margin-top: 24px; align-items: center; }
.btn-primary {
  display: flex; align-items: center; gap: 8px;
  background: var(--teal);
  color: var(--navy);
  border: none;
  border-radius: 8px;
  padding: 11px 28px;
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  transition: background .2s, transform .1s;
}
.btn-primary:hover { background: var(--teal-dim); transform: translateY(-1px); }
.btn-secondary {
  background: transparent;
  color: var(--navy);
  border: 1.5px solid var(--border);
  border-radius: 8px;
  padding: 11px 22px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: border-color .2s, background .2s;
}
.btn-secondary:hover { border-color: var(--navy); background: #F7F9FC; }

/* ERROR */
.error-msg {
  margin-top: 16px;
  background: #FFF0F0;
  border: 1px solid #FFC0C0;
  color: #C0392B;
  border-radius: 8px;
  padding: 10px 16px;
  font-size: 13px;
}
.hidden { display: none !important; }

/* RESULT GRID */
.result-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 16px;
}
.result-item {
  background: #F7F9FC;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 18px;
}
.result-item.highlight {
  background: var(--navy);
  border-color: var(--navy);
  grid-column: span 2;
}
.result-label {
  display: block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 6px;
}
.result-item.highlight .result-label { color: rgba(255,255,255,.5); }
.result-val { display: block; word-break: break-all; }
.result-item.highlight .result-val { color: var(--teal); }

/* MONO */
.mono { font-family: 'Cascadia Code', 'Consolas', monospace; }
.small { font-size: 12px; }
.tiny  { font-size: 11px; }
.big   { font-size: 22px; font-weight: 700; letter-spacing: 2px; }

/* KEY SCHEDULE */
.ks-overview, .cd-init {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 20px;
}
.ks-box {
  background: #F7F9FC;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 16px;
  flex: 1;
}
.ks-box.half { flex: 1; }
.ks-label {
  font-size: 12px;
  font-weight: 700;
  color: var(--muted);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: .5px;
}
.arrow { font-size: 24px; color: var(--teal); font-weight: 700; flex-shrink: 0; }

/* TABLES */
.table-wrap { overflow-x: auto; }
.des-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}
.des-table th {
  background: var(--navy);
  color: rgba(255,255,255,.8);
  padding: 10px 14px;
  text-align: left;
  font-size: 12px;
  font-weight: 600;
  white-space: nowrap;
}
.des-table td {
  padding: 9px 14px;
  border-bottom: 1px solid var(--border);
  vertical-align: middle;
}
.des-table tbody tr:hover { background: #F7F9FC; }
.des-table .center { text-align: center; }

/* IP SECTION */
.perm-grid {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}
.perm-box {
  width: 100%;
  background: #F7F9FC;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 18px;
}
.perm-box.highlight-box {
  background: var(--navy);
  border-color: var(--navy);
}
.perm-box.highlight-box .perm-label { color: rgba(255,255,255,.5); }
.perm-box.highlight-box .mono { color: var(--teal); }
.perm-label {
  font-size: 12px;
  font-weight: 700;
  color: var(--muted);
  margin-bottom: 6px;
  text-transform: uppercase;
}
.arrow-down {
  font-size: 18px;
  font-weight: 700;
  color: var(--teal);
  padding: 4px 0;
}
.bits-display {
  word-break: break-all;
  letter-spacing: 2px;
  line-height: 1.8;
}
.lr-split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 16px;
  width: 100%;
}
.lr-box {
  background: #F7F9FC;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 18px;
}
.lr-label {
  font-size: 12px;
  font-weight: 700;
  color: var(--muted);
  margin-bottom: 6px;
  text-transform: uppercase;
}

/* ROUNDS */
.section-desc { color: var(--muted); font-size: 14px; margin-bottom: 20px; margin-top: -10px; }
.round-item {
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 10px;
  overflow: hidden;
}
.round-header {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 14px 20px;
  cursor: pointer;
  background: #FAFBFC;
  transition: background .15s;
  user-select: none;
}
.round-header:hover { background: #F0F4F8; }
.round-num {
  font-size: 13px;
  font-weight: 700;
  color: var(--navy);
  background: var(--border);
  padding: 3px 12px;
  border-radius: 20px;
  flex-shrink: 0;
}
.round-preview { font-size: 13px; color: var(--muted); flex: 1; }
.round-toggle { color: var(--teal); font-size: 14px; font-weight: 700; }

.round-body { padding: 20px; background: #fff; border-top: 1px solid var(--border); }
.round-detail-grid { display: flex; flex-direction: column; gap: 8px; margin-bottom: 24px; }
.rd-row {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 12px;
  align-items: start;
  padding: 8px 12px;
  border-radius: 6px;
}
.rd-row:nth-child(odd) { background: #F7F9FC; }
.rd-row.highlight-row { background: rgba(0,194,168,.08); border: 1px solid rgba(0,194,168,.2); }
.rd-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--navy);
}

.sbox-section { margin-top: 16px; }
.sbox-title {
  font-size: 13px;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 10px;
  text-transform: uppercase;
  letter-spacing: .5px;
}
.sbox-table { font-size: 12px; }

/* ROUND TRIP */
.round-trip {
  margin-top: 12px;
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 13px;
}
.round-trip.pass { background: #E8F8F5; border: 1px solid #A9DFCF; color: #1E8449; }
.round-trip.fail { background: #FFF0F0; border: 1px solid #FFC0C0; color: #C0392B; }

/* FOOTER */
.site-footer {
  background: var(--navy);
  color: rgba(255,255,255,.35);
  text-align: center;
  padding: 20px;
  font-size: 13px;
}

/* =========================================
   PROFESSIONAL UI UPGRADE
========================================= */

body{
background:
linear-gradient(
180deg,
#f8fafc 0%,
#eef6ff 50%,
#f8fafc 100%
);
min-width:auto!important;
}

/* CARD */
.card{
border:none;
border-radius:18px;
box-shadow:
0 8px 30px rgba(15,27,45,.08);
transition:.25s;
}

.card:hover{
transform:translateY(-3px);
box-shadow:
0 16px 40px rgba(15,27,45,.12);
}

/* HEADER */
.site-header{
background:
linear-gradient(
135deg,
#0F1B2D 0%,
#1A2D45 50%,
#00A08A 100%
);
}

.site-header h1{
font-size:56px;
}

.header-sub{
font-size:17px;
}

/* DASHBOARD */
.dashboard-grid{
display:grid;
grid-template-columns:repeat(auto-fit,minmax(200px,1fr));
gap:18px;
}

.dashboard-item{
background:white;
border-radius:14px;
padding:22px;
border:1px solid #e5e7eb;
box-shadow:
0 4px 14px rgba(0,0,0,.05);
}

.dashboard-title{
font-size:.8rem;
color:#64748b;
text-transform:uppercase;
letter-spacing:1px;
}

.dashboard-value{
font-size:1.5rem;
font-weight:700;
color:#00A08A;
}

/* INPUT */
.field-group input,
.field-group select{
background:white;
border:1.5px solid #dbe3ee;
border-radius:12px;
padding:14px;
}

.field-group input:focus,
.field-group select:focus{
transform:translateY(-1px);
}

/* BUTTON */
.btn-primary{
border-radius:12px;
box-shadow:
0 6px 18px rgba(0,194,168,.25);
}

.btn-secondary{
border-radius:12px;
}

.btn-primary:hover,
.btn-secondary:hover{
transform:translateY(-2px);
}

/* RESULT */
.result-grid{
gap:20px;
}

.result-item{
border-radius:14px;
}

.result-item.highlight{
background:
linear-gradient(
135deg,
#0F1B2D,
#00A08A
);
}

.result-item.highlight .big{
font-size:30px;
letter-spacing:3px;
}

/* TABLE */
.des-table{
overflow:hidden;
border-radius:12px;
}

.des-table th{
background:
linear-gradient(
135deg,
#0F1B2D,
#1A2D45
);
}

.des-table tbody tr:hover{
background:#f0fdfa;
}

/* ROUND */
.round-item{
border-radius:14px;
overflow:hidden;
transition:.25s;
}

.round-item:hover{
box-shadow:
0 8px 18px rgba(0,0,0,.08);
}

.round-header{
padding:18px 22px;
}

.round-num{
background:#e6fffb;
color:#0f766e;
}

.round-toggle{
font-size:18px;
}

/* OUTPUT BOX */
.perm-box,
.lr-box,
.ks-box{
border-radius:14px;
}

/* RESPONSIVE */
@media(max-width:900px){

.input-grid,
.result-grid,
.lr-split{
grid-template-columns:1fr;
}

.container{
padding:20px;
}

.card{
padding:22px;
}

.site-header h1{
font-size:38px;
}

.rd-row{
grid-template-columns:1fr;
}

body{
min-width:auto;
}
}