/* X36 Cipher App. Lesson 9's slate palette, one screen, nothing moves unless the child pressed something. */
:root{
  --bg:#0b0e13; --bg-2:#10151c; --ink:#e3eaf3; --dim:#6b7a8c; --line:#1d2632; --panel:#0f141b;
  --accent:#7cc7ff; --accent-ink:#06121c; --red:#ff5c6b; --glow:rgba(124,199,255,.32);
}
*{box-sizing:border-box}
[hidden]{display:none!important}
html,body{margin:0;min-height:100%}
body{background:radial-gradient(120% 90% at 50% 30%, var(--bg-2), var(--bg) 70%);color:var(--ink);
  font-family:"JetBrains Mono",ui-monospace,Menlo,monospace;font-size:15px;line-height:1.5}

.atmo,.atmo>div{position:fixed;inset:0;pointer-events:none}
.atmo{z-index:0}
.atmo-glow{background:radial-gradient(ellipse 55% 45% at 18% 8%, var(--glow), transparent 65%),
  radial-gradient(ellipse 50% 40% at 85% 95%, rgba(255,92,107,.06), transparent 60%);opacity:.45}
.atmo-grid{background:repeating-linear-gradient(0deg, var(--line) 0 1px, transparent 1px 56px),
  repeating-linear-gradient(90deg, var(--line) 0 1px, transparent 1px 56px);opacity:.3;
  mask-image:radial-gradient(ellipse 70% 65% at 50% 42%, #000 30%, transparent 78%)}

.app{position:relative;z-index:1;max-width:880px;margin:0 auto;padding:22px 20px 28px;display:grid;gap:18px}

.top{display:flex;justify-content:space-between;align-items:center;gap:14px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:12px}
.stamp{border:2px solid var(--red);color:var(--red);font-weight:800;letter-spacing:.3em;padding:4px 8px 4px 12px;transform:rotate(-4deg);
  text-shadow:0 0 14px rgba(255,92,107,.45)}
.name{font-weight:800;letter-spacing:.24em;color:var(--ink)}
.modes{display:flex;border:1px solid var(--line);border-radius:3px;overflow:hidden}
.mode{font-family:inherit;font-weight:700;font-size:.78rem;letter-spacing:.18em;padding:9px 16px;background:transparent;color:var(--dim);
  border:0;cursor:pointer}
.mode.on{background:var(--accent);color:var(--accent-ink)}
.mode:not(.on):hover{color:var(--ink)}

.lbl{display:block;margin:0 0 6px;font-size:.68rem;letter-spacing:.2em;color:var(--dim);text-transform:uppercase}

.keyrow{display:grid;grid-template-columns:auto auto 1fr;align-items:center;gap:6px 16px}
.keyrow .lbl{margin:0}
.keybox{display:flex;align-items:center;gap:6px}
.key{width:11ch;text-align:center;font-family:inherit;font-weight:800;font-size:1.3rem;letter-spacing:.12em;color:var(--accent);
  background:var(--panel);border:1px solid var(--line);border-radius:3px;padding:6px 8px;outline:none;text-shadow:0 0 12px var(--glow)}
.key:focus{border-color:var(--accent)}
body[data-mode="vigenere"] .key{width:16ch;font-size:1.1rem}
body[data-mode="vigenere"] .turn{visibility:hidden}
.turn{width:34px;height:34px;border-radius:50%;border:1px solid var(--line);background:transparent;color:var(--ink);font-size:1.1rem;
  line-height:1;cursor:pointer;font-family:inherit}
.turn:hover{border-color:var(--accent);color:var(--accent)}
.help{margin:0;color:var(--dim);font-size:.82rem}
.help.bad{color:var(--red)}

.boxes{display:grid;grid-template-columns:1fr auto 1fr;gap:14px;align-items:stretch}
.box{display:flex;flex-direction:column;min-width:0}
textarea{width:100%;flex:1;min-height:96px;resize:vertical;font-family:inherit;font-size:1.05rem;line-height:1.5;color:var(--ink);
  background:var(--panel);border:1px solid var(--line);border-radius:3px;padding:10px 12px;outline:none}
textarea:focus{border-color:var(--accent);box-shadow:0 0 0 1px var(--accent) inset}
#result{color:var(--accent);text-shadow:0 0 10px var(--glow);letter-spacing:.04em}
.actions{display:flex;flex-direction:column;justify-content:center;gap:10px;padding-top:20px}
.action{font-family:inherit;font-weight:800;font-size:.82rem;letter-spacing:.22em;padding:12px 18px;cursor:pointer;border-radius:3px;
  background:var(--accent);color:var(--accent-ink);border:1px solid var(--accent);box-shadow:0 0 22px var(--glow);white-space:nowrap}
.action:hover{filter:brightness(1.08)}
.action.ghost{background:transparent;color:var(--accent);box-shadow:none}
.tools{display:flex;align-items:center;gap:8px;margin-top:8px;flex-wrap:wrap}
.small{font-family:inherit;font-size:.66rem;letter-spacing:.18em;padding:6px 10px;background:none;border:1px solid var(--line);color:var(--dim);
  cursor:pointer;border-radius:3px}
.small:hover{border-color:var(--accent);color:var(--accent)}
.status{color:var(--dim);font-size:.78rem;margin-left:auto}

.working{border-top:1px solid var(--line);padding-top:14px}
.row{display:flex;flex-wrap:wrap;gap:8px}
.tile{display:grid;justify-items:center;gap:2px;width:44px;padding:6px 0;background:var(--panel);border:1px solid var(--line);border-radius:3px}
.tile .from{font-weight:700;color:var(--ink)}
.tile .by{font-size:.62rem;color:var(--dim)}
.tile .to{font-weight:800;color:var(--accent);text-shadow:0 0 10px var(--glow)}
.more{align-self:center;color:var(--dim);font-size:.78rem;padding:0 6px}

.foot{display:flex;align-items:center;gap:14px;border-top:1px solid var(--line);padding-top:14px;flex-wrap:wrap}
.fine{color:var(--dim);font-size:.78rem}
.plan{display:grid;grid-template-columns:1fr 1fr;gap:18px}
.plan img{width:100%;border:1px solid var(--line);border-radius:3px;background:#fbf8f1}
.plan pre{margin:0;white-space:pre-wrap;font-size:.8rem;line-height:1.55;color:var(--ink);background:var(--panel);border:1px solid var(--line);
  border-radius:3px;padding:12px}

@media (max-width:700px){
  .boxes{grid-template-columns:1fr}
  .actions{flex-direction:row;padding-top:0}
  .action{flex:1;text-align:center}
  .keyrow{grid-template-columns:auto 1fr}
  .keyrow .help{grid-column:1 / -1}
  .plan{grid-template-columns:1fr}
}