:root {
  --background: #fcfcfc;
  --foreground: #14181d;
  --card: #ffffff;
  --primary: #1aa89a;
  --primary-foreground: #ffffff;
  --secondary: #e6f6fb;
  --secondary-foreground: #14181d;
  --muted: #f1f4f6;
  --muted-foreground: #64707c;
  --accent-bg: #dff1f7;
  --border: #e2e8ec;
  --input-border: #d7dee3;
  --destructive: #e5484d;
  --radius: 0.625rem;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.03), 0 1px 3px 0 rgb(0 0 0 / 0.06);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.05), 0 2px 4px -2px rgb(0 0 0 / 0.05);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.07), 0 4px 6px -4px rgb(0 0 0 / 0.05);
}

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

html { -webkit-text-size-adjust: 100%; }

body {
  font-family: 'DM Sans', system-ui, -apple-system, sans-serif;
  background: var(--background);
  color: var(--foreground);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

.container { max-width: 64rem; margin: 0 auto; padding-left: 1rem; padding-right: 1rem; }

.accent { color: var(--primary); }

/* Header */
.site-header {
  border-bottom: 1px solid var(--border);
  background: rgba(255,255,255,0.8);
  backdrop-filter: blur(8px);
  position: sticky; top: 0; z-index: 50;
}
.header-inner { display: flex; align-items: center; height: 60px; }
.brand { display: flex; align-items: center; gap: 0.6rem; text-decoration: none; color: var(--foreground); }
.brand-mark {
  width: 34px; height: 34px; border-radius: 9px;
  background: var(--primary); color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-family: 'Plus Jakarta Sans', sans-serif; font-weight: 800; font-size: 1.15rem;
}
.brand-name { font-family: 'Plus Jakarta Sans', sans-serif; font-weight: 700; font-size: 1.15rem; }

/* Hero */
.hero { background: linear-gradient(to bottom, rgba(26,168,154,0.05), transparent 60%); }
.hero-inner { padding-top: 3rem; padding-bottom: 2rem; }
.hero-title {
  font-family: 'Plus Jakarta Sans', sans-serif; font-weight: 800;
  font-size: clamp(2.25rem, 5vw, 3rem); text-align: center; letter-spacing: -0.02em; margin-bottom: 0.75rem;
}
.hero-sub { text-align: center; color: var(--muted-foreground); font-size: 1.125rem; max-width: 36rem; margin: 0 auto 2rem; }

/* Card */
.card { background: var(--card); border-radius: 0.75rem; box-shadow: var(--shadow-lg); }
.form-card { padding: 1.5rem; }
@media (min-width: 640px) { .form-card { padding: 2rem; } }

/* Input */
.input-wrap { position: relative; }
.input-icon { position: absolute; left: 1rem; top: 50%; transform: translateY(-50%); width: 20px; height: 20px; color: var(--muted-foreground); }
.letters-input {
  width: 100%; height: 3.5rem; padding: 0 1rem 0 3rem;
  border-radius: var(--radius); border: 1px solid var(--input-border); background: var(--background);
  font-family: 'JetBrains Mono', monospace; font-size: 1.125rem; letter-spacing: 0.25em; text-transform: uppercase;
  outline: none; transition: box-shadow .15s, border-color .15s;
}
.letters-input::placeholder { text-transform: none; letter-spacing: normal; font-family: 'DM Sans', sans-serif; font-size: 1rem; color: var(--muted-foreground); }
.letters-input:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(26,168,154,0.25); }

/* Buttons */
.btn-row { display: flex; flex-wrap: wrap; gap: 0.75rem; margin-top: 1rem; }
.btn {
  display: inline-flex; align-items: center; gap: 0.5rem;
  height: 2.75rem; padding: 0 1.5rem; border-radius: var(--radius);
  font-family: 'DM Sans', sans-serif; font-size: 1rem; font-weight: 600;
  border: none; cursor: pointer; transition: background .15s, opacity .15s, transform .05s;
}
.btn:active { transform: translateY(1px); }
.btn-icon { width: 18px; height: 18px; }
.btn-primary { background: var(--primary); color: var(--primary-foreground); }
.btn-primary:hover { background: #17968a; }
.btn-primary:disabled { opacity: 0.5; cursor: not-allowed; }
.btn-secondary { background: var(--muted); color: var(--foreground); }
.btn-secondary:hover { background: var(--accent-bg); }

/* Dictionary pills */
.dict-row { display: flex; flex-wrap: wrap; align-items: center; gap: 0.5rem; margin-top: 1rem; }
.dict-label { font-size: 0.875rem; color: var(--muted-foreground); }
.dict-pill {
  padding: 0.375rem 0.75rem; border-radius: 9999px; border: none; cursor: pointer;
  font-size: 0.875rem; font-weight: 500; font-family: inherit;
  background: var(--muted); color: var(--muted-foreground); transition: background .15s, color .15s;
}
.dict-pill:hover { background: var(--accent-bg); }
.dict-pill.active { background: var(--primary); color: var(--primary-foreground); }
.dict-desc { font-size: 0.75rem; opacity: 0.7; margin-left: 0.25rem; }
@media (max-width: 640px) { .dict-desc { display: none; } }

/* Filters */
.filters { display: grid; grid-template-columns: 1fr; gap: 0.75rem; margin-top: 1rem; padding-top: 1rem; border-top: 1px solid var(--border); }
@media (min-width: 640px) { .filters { grid-template-columns: repeat(3, 1fr); } }
.filters.hidden { display: none; }
.filter-field label { display: block; font-size: 0.75rem; font-weight: 500; color: var(--muted-foreground); margin-bottom: 0.25rem; }
.filter-input {
  width: 100%; height: 2.25rem; padding: 0 0.75rem;
  border-radius: var(--radius); border: 1px solid var(--input-border); background: var(--background);
  font-family: 'JetBrains Mono', monospace; font-size: 0.875rem; outline: none;
}
.filter-input:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(26,168,154,0.25); }

/* Status */
.status { margin-top: 1rem; text-align: center; color: var(--muted-foreground); font-size: 0.95rem; min-height: 1.2rem; }
.status.error { color: var(--destructive); }

/* Results */
.results { margin-top: 2rem; }
.results-summary { display: flex; align-items: center; justify-content: space-between; margin-bottom: 1rem; }
.results-summary h2 { font-family: 'Plus Jakarta Sans', sans-serif; font-size: 1.25rem; font-weight: 700; letter-spacing: -0.01em; }
.results-summary .letters-tag { font-family: 'JetBrains Mono', monospace; text-transform: uppercase; color: var(--muted-foreground); font-size: 0.875rem; }

.length-group { background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow-md); overflow: hidden; margin-bottom: 0.75rem; }
.group-header {
  width: 100%; display: flex; align-items: center; justify-content: space-between;
  padding: 0.75rem 1rem; background: none; border: none; cursor: pointer; font-family: inherit; text-align: left;
}
.group-header:hover { background: rgba(0,0,0,0.02); }
.group-header-left { display: flex; align-items: center; gap: 0.5rem; }
.group-title { font-family: 'Plus Jakarta Sans', sans-serif; font-weight: 600; }
.group-count { font-size: 0.75rem; color: var(--muted-foreground); background: var(--muted); padding: 0.1rem 0.5rem; border-radius: 9999px; }
.hash { color: var(--primary); font-weight: 700; font-family: 'JetBrains Mono', monospace; }
.chevron { color: var(--muted-foreground); font-size: 0.85rem; }
.word-wrap { padding: 0 1rem 1rem; display: flex; flex-wrap: wrap; gap: 0.5rem; }
.word-wrap.collapsed { display: none; }
.word-chip {
  display: inline-flex; align-items: center; gap: 0.25rem;
  padding: 0.375rem 0.75rem; border-radius: 0.5rem;
  background: var(--secondary); color: var(--secondary-foreground);
  font-family: 'JetBrains Mono', monospace; font-size: 0.875rem; text-transform: uppercase; letter-spacing: 0.03em;
  text-decoration: none; box-shadow: var(--shadow-sm); transition: background .15s, color .15s;
}
.word-chip:hover { background: var(--primary); color: var(--primary-foreground); }

.empty { text-align: center; padding: 2rem 0; }
.empty p { color: var(--muted-foreground); }
.empty .big { font-size: 1.125rem; }
.empty .mono { font-family: 'JetBrains Mono', monospace; font-weight: 700; text-transform: uppercase; color: var(--foreground); }

/* SEO */
.seo { padding-bottom: 3rem; margin-top: 2rem; }
.seo-heading { font-family: 'Plus Jakarta Sans', sans-serif; font-size: 1.5rem; font-weight: 700; text-align: center; letter-spacing: -0.01em; margin-bottom: 2rem; }
.seo-grid { display: grid; grid-template-columns: 1fr; gap: 1.5rem; }
@media (min-width: 768px) { .seo-grid { grid-template-columns: repeat(2, 1fr); } }
.seo-card { padding: 1.5rem; }
.seo-card h3 { font-family: 'Plus Jakarta Sans', sans-serif; font-size: 1.125rem; font-weight: 700; letter-spacing: -0.01em; margin-bottom: 0.75rem; }
.seo-card p { color: var(--muted-foreground); font-size: 0.875rem; margin-bottom: 0.5rem; }
.seo-card code { background: var(--muted); padding: 0.1rem 0.35rem; border-radius: 4px; font-family: 'JetBrains Mono', monospace; font-size: 0.8rem; }
.seo-card strong { color: var(--foreground); }

/* Footer */
.site-footer { border-top: 1px solid var(--border); padding: 1.5rem 0; margin-top: 1rem; }
.site-footer p { text-align: center; color: var(--muted-foreground); font-size: 0.85rem; }

.spinner { display: inline-block; width: 18px; height: 18px; border: 2px solid rgba(255,255,255,0.4); border-top-color: #fff; border-radius: 50%; animation: spin .7s linear infinite; vertical-align: middle; }
@keyframes spin { to { transform: rotate(360deg); } }