:root {
  --bg: #f4f6fb;
  --card: #ffffff;
  --text: #1f2330;
  --muted: #6b7280;
  --primary: #3b5bfd;
  --primary-dark: #2c47d6;
  --border: #e3e7f2;
  --error: #d92d20;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: linear-gradient(180deg, #eef1fb 0%, var(--bg) 320px);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.6;
}

.page {
  max-width: 860px;
  margin: 0 auto;
  padding: 36px 20px 64px;
}

.hero h1 { margin: 0 0 8px; font-size: 28px; }
.hero p { margin: 0 0 22px; color: var(--muted); font-size: 14px; }

a { color: var(--primary); text-decoration: none; }

.tabs {
  display: flex;
  gap: 6px;
  background: #e9ecf7;
  padding: 5px;
  border-radius: 12px;
  margin-bottom: 18px;
}

.tab {
  flex: 1;
  border: none;
  background: transparent;
  padding: 9px 12px;
  border-radius: 9px;
  font-size: 14px;
  cursor: pointer;
  color: var(--muted);
}

.tab.is-active {
  background: #fff;
  color: var(--text);
  font-weight: 600;
  box-shadow: 0 2px 8px rgba(31, 35, 48, .08);
}

.panel { display: none; }
.panel.is-active { display: block; }

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 22px 22px 26px;
  margin-bottom: 20px;
  box-shadow: 0 8px 24px rgba(31, 35, 48, .05);
}

.card h2 { margin: 0 0 10px; font-size: 18px; }

.card h3 {
  margin: 22px 0 10px;
  font-size: 13px;
  color: var(--muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .5px;
}

.muted { color: var(--muted); font-size: 13px; }

.dropzone {
  border: 2px dashed #c7cfe6;
  border-radius: 12px;
  padding: 26px 16px;
  text-align: center;
  cursor: pointer;
  background: #fbfcff;
  transition: border-color .15s, background .15s;
}

.dropzone:hover,
.dropzone:focus,
.dropzone.is-drag {
  border-color: var(--primary);
  background: #f1f4ff;
  outline: none;
}

.drop-icon { font-size: 22px; color: var(--primary); }
.drop-title { margin: 6px 0 2px; font-weight: 600; }

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

.chip {
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 999px;
  padding: 6px 14px;
  cursor: pointer;
  font-size: 13px;
  color: var(--text);
  transition: all .15s;
}

.chip:hover { border-color: var(--primary); color: var(--primary); }
.chip.is-active { background: var(--primary); border-color: var(--primary); color: #fff; }

.custom-ttl {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.custom-ttl input[type="number"] {
  width: 84px;
  padding: 6px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
}

.custom-ttl select,
.text-input {
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  background: #fff;
  color: var(--text);
}

.text-input { width: 100%; margin-bottom: 10px; }

.paste-area {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--border);
  border-radius: 10px;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: 13px;
  line-height: 1.6;
  resize: vertical;
  color: var(--text);
}

.paste-area:focus,
.text-input:focus,
.code-input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(59, 91, 253, .12);
}

.btn {
  display: inline-block;
  border: 1px solid transparent;
  border-radius: 10px;
  padding: 10px 20px;
  font-size: 15px;
  cursor: pointer;
  text-decoration: none;
  text-align: center;
  transition: background .15s, border-color .15s, opacity .15s;
}

.btn-primary { background: var(--primary); color: #fff; margin-top: 18px; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-primary[disabled] { opacity: .45; cursor: not-allowed; }

.btn-ghost {
  background: #fff;
  border-color: var(--border);
  color: var(--text);
  padding: 6px 14px;
  font-size: 13px;
}

.btn-ghost:hover { border-color: var(--primary); color: var(--primary); }

.progress-wrap { margin-top: 18px; }

.progress {
  height: 10px;
  background: #e9ecf7;
  border-radius: 999px;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, #5b78ff, #3b5bfd);
  border-radius: 999px;
  transition: width .2s ease;
}

.progress-wrap .muted { margin-top: 6px; }

.result {
  margin-top: 18px;
  padding: 16px 18px;
  border: 1px solid #d7e2ff;
  background: #f5f8ff;
  border-radius: 12px;
}

.result-label { margin: 0 0 6px; font-size: 14px; color: var(--muted); }
.result .btn-primary { margin-top: 12px; }

.code-row { display: flex; align-items: center; gap: 12px; }

.code {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: 32px;
  font-weight: 700;
  letter-spacing: 8px;
  color: var(--primary);
}

.error { margin: 14px 0 0; color: var(--error); font-size: 14px; }

.pickup-row { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 12px; }
.pickup-row .btn-primary { margin-top: 0; }

.code-input {
  flex: 1 1 220px;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  font-size: 20px;
  letter-spacing: 6px;
  font-family: "SFMono-Regular", Consolas, monospace;
}

.preview,
.content-block {
  background: #12151f;
  color: #e6e9f5;
  border-radius: 10px;
  padding: 14px;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: 13px;
  line-height: 1.6;
  overflow: auto;
  white-space: pre-wrap;
  word-break: break-word;
}

.preview { max-height: 260px; margin: 12px 0 0; }
.content-block { max-height: 70vh; margin: 12px 0 0; }

.toolbar { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.spacer { flex: 1; }

footer { text-align: center; margin-top: 8px; }

@media (max-width: 520px) {
  .page { padding: 22px 14px 48px; }
  .code { font-size: 26px; letter-spacing: 5px; }
  .tab { font-size: 13px; padding: 8px 6px; }
}