:root {
  --bg: #f6f7fb;
  --panel: #ffffff;
  --panel-2: #f1f3f8;
  --border: #e3e6ef;
  --border-strong: #ced3e0;
  --text: #121726;
  --text-soft: #3c4252;
  --muted: #6b7385;
  --accent: #4f6cf5;
  --accent-strong: #3a56df;
  --danger: #d0353c;
  --warn: #b26a00;
  --ok: #0a8a4a;
  --shadow: 0 1px 2px rgba(18, 23, 38, 0.05), 0 4px 16px rgba(18, 23, 38, 0.06);
  --radius: 12px;
  --radius-sm: 8px;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Pretendard", "Segoe UI", Roboto, sans-serif;
  font-size: 15px;
  line-height: 1.55;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.site-header {
  max-width: 720px;
  margin: 0 auto;
  padding: 40px 24px 12px;
  text-align: center;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 700;
  font-size: 22px;
  letter-spacing: -0.01em;
}

.brand-mark {
  display: inline-block;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, #7d97ff, #3a56df 70%);
  box-shadow: 0 4px 14px rgba(79, 108, 245, 0.35);
  color: transparent;
}

.tagline {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 24px 24px 60px;
}


.view h1 {
  font-size: 24px;
  margin: 6px 0 8px;
  letter-spacing: -0.01em;
  color: var(--text);
}

.desc {
  color: var(--text-soft);
  margin: 0 0 18px;
  font-size: 14px;
  line-height: 1.6;
}

/* ---------- Gate (첫 화면 선택) ---------- */
.gate-title {
  text-align: center;
  font-size: 26px;
  margin: 18px 0 6px;
  letter-spacing: -0.01em;
}

#view-gate > .desc {
  text-align: center;
  margin-bottom: 26px;
}

.gate-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
  margin-bottom: 28px;
}

.gate-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 26px 24px 24px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  color: var(--text);
  text-decoration: none;
  transition: border-color 0.15s, transform 0.08s, box-shadow 0.15s;
  min-height: 180px;
}
.gate-card:hover {
  border-color: var(--accent);
  transform: translateY(-1px);
  box-shadow: 0 2px 4px rgba(18, 23, 38, 0.06), 0 10px 28px rgba(79, 108, 245, 0.14);
  text-decoration: none;
}
.gate-card:active { transform: translateY(0); }
.gate-icon {
  font-size: 30px;
  line-height: 1;
}
.gate-card-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
}
.gate-card-desc {
  font-size: 13.5px;
  color: var(--text-soft);
  line-height: 1.55;
  flex: 1;
}
.gate-cta {
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
  margin-top: 6px;
}

/* ---------- Gate 미니 프리뷰 ---------- */
.preview {
  display: flex;
  flex-direction: column;
  gap: 5px;
  margin-top: 14px;
  padding: 12px 10px 10px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  pointer-events: none;
  user-select: none;
}
.pv-label {
  font-size: 8px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
}
.pv-label-s {
  font-size: 7px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted);
}
.pv-textarea {
  display: block;
  padding: 6px 7px;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 4px;
  font-family: var(--mono);
  font-size: 9px;
  color: var(--text-soft);
  min-height: 24px;
  line-height: 1.3;
}
.pv-input {
  display: block;
  padding: 5px 7px;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 4px;
  font-family: var(--mono);
  font-size: 9px;
  color: var(--text-soft);
}
.pv-row {
  display: flex;
  align-items: center;
  gap: 6px;
}
.pv-select {
  display: inline-block;
  padding: 3px 8px;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 4px;
  font-size: 8px;
  color: var(--text-soft);
}
.pv-btn {
  display: block;
  padding: 5px 0;
  background: var(--accent);
  color: #ffffff;
  border-radius: 4px;
  text-align: center;
  font-size: 8px;
  font-weight: 700;
}
.pv-divider {
  height: 0;
  border-top: 1px dashed var(--border);
  margin: 3px 0;
}
.pv-key {
  display: block;
  padding: 4px 7px;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 4px;
  font-family: var(--mono);
  font-size: 8px;
  color: var(--accent-strong);
  letter-spacing: 0.02em;
}
.pv-result {
  display: flex;
  flex-direction: column;
  gap: 3px;
}
.pv-value {
  display: block;
  padding: 5px 7px;
  background: #f7f9ff;
  border: 1px solid var(--border);
  border-radius: 4px;
  font-family: var(--mono);
  font-size: 9px;
  color: #0f1b3c;
}

/* ---------- 보내기/받기 뷰: 폼/결과 카드를 2/3 너비로 축소, 가운데 정렬 ---------- */
#view-send .card,
#view-open .card {
  max-width: 480px;
  margin-left: auto;
  margin-right: auto;
}

/* ---------- Back link ---------- */
.back-link {
  display: inline-block;
  font-size: 13px;
  color: var(--muted);
  text-decoration: none;
  margin-bottom: 14px;
  padding: 4px 0;
}
.back-link:hover { color: var(--accent); text-decoration: none; }

/* ---------- "보내는/받는 방법" 소제목 ---------- */
.how {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin: 32px 0 12px;
  padding: 0;
}

.steps {
  list-style: none;
  counter-reset: step;
  padding: 0;
  margin: 0 0 22px;
  display: grid;
  gap: 10px;
}
.steps li {
  counter-increment: step;
  position: relative;
  padding: 12px 14px 12px 48px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 14px;
  color: var(--text-soft);
  box-shadow: var(--shadow);
}
.steps li::before {
  content: counter(step);
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  width: 24px;
  height: 24px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--accent);
  color: #ffffff;
  font-weight: 700;
  font-size: 12px;
  border-radius: 50%;
}
.steps strong { color: var(--text); font-weight: 600; }

.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  margin-bottom: 16px;
  box-shadow: var(--shadow);
}

.card h2 {
  margin: 0 0 8px;
  font-size: 18px;
}

.field {
  display: block;
  margin-bottom: 16px;
}

.field .label {
  display: block;
  font-size: 12px;
  font-weight: 600;
  color: var(--muted);
  margin-bottom: 6px;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.field .hint {
  display: block;
  font-size: 12px;
  color: var(--muted);
  margin-top: 6px;
}

textarea,
input[type="text"],
select {
  width: 100%;
  background: #ffffff;
  color: var(--text);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  padding: 11px 13px;
  font-size: 14px;
  font-family: inherit;
  outline: none;
  transition: border-color 0.15s, box-shadow 0.15s;
}

textarea {
  font-family: var(--mono);
  resize: vertical;
  min-height: 140px;
}

textarea::placeholder,
input[type="text"]::placeholder {
  color: #a4abbc;
}

textarea:focus,
input[type="text"]:focus,
select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(79, 108, 245, 0.18);
}

button {
  font-family: inherit;
  cursor: pointer;
  font-size: 14px;
  font-weight: 600;
  border-radius: var(--radius-sm);
  padding: 10px 16px;
  border: 1px solid transparent;
  transition: background 0.15s, border-color 0.15s, color 0.15s, transform 0.05s;
}
button:active { transform: translateY(1px); }

.primary {
  background: var(--accent-strong);
  color: white;
  border-color: var(--accent-strong);
  width: 100%;
}
.primary:hover { background: var(--accent); border-color: var(--accent); }
.primary:disabled { background: var(--border); border-color: var(--border); color: var(--muted); cursor: not-allowed; }

.secondary {
  background: #ffffff;
  color: var(--text);
  border-color: var(--border-strong);
}
.secondary:hover { border-color: var(--accent); color: var(--accent); }

.ghost {
  background: transparent;
  color: var(--muted);
  border-color: var(--border-strong);
}
.ghost:hover { color: var(--text); border-color: var(--accent); }

.copy-row {
  display: flex;
  gap: 8px;
}

.copy-row input {
  font-family: var(--mono);
}

.meta {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  padding: 12px 14px;
  margin: 12px 0 16px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-soft);
}
.meta dt {
  font-size: 11px;
  text-transform: uppercase;
  color: var(--muted);
  letter-spacing: 0.04em;
  margin: 0 0 2px;
}
.meta dd { margin: 0; font-family: var(--mono); font-size: 13px; }

.row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.value-box {
  background: #f7f9ff;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  font-family: var(--mono);
  font-size: 13.5px;
  white-space: pre-wrap;
  word-break: break-all;
  max-height: 360px;
  overflow: auto;
  margin: 12px 0;
  color: #0f1b3c;
}

.warn {
  background: #fff6e5;
  color: var(--warn);
  border: 1px solid #ffd699;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  margin: 4px 0 14px;
}

.error {
  border-color: #f2bcbf;
  background: #fdf2f3;
}
.error h2 { color: var(--danger); }
.error p  { color: #8e1d22; }

.site-footer {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 24px 40px;
  color: var(--muted);
  font-size: 12px;
  text-align: center;
}

.flash {
  position: fixed;
  left: 50%;
  bottom: 30px;
  transform: translateX(-50%);
  background: #1b2140;
  border: 1px solid #1b2140;
  color: #ffffff;
  padding: 11px 18px;
  border-radius: 999px;
  font-size: 13px;
  box-shadow: 0 12px 28px rgba(18, 23, 38, 0.25);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s, transform 0.2s;
}
.flash.show {
  opacity: 1;
  transform: translateX(-50%) translateY(-6px);
}

@media (max-width: 620px) {
  .gate-grid { grid-template-columns: 1fr; }
}

@media (max-width: 520px) {
  .meta { grid-template-columns: 1fr; }
  .copy-row { flex-direction: column; }
  .copy-row .secondary { width: 100%; }
}