/* ============================================================
   style.css — AI Detector UI
   MUI-inspired: Roboto, elevation shadows, ripple colors,
   8px grid, 4px border-radius base
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@400;500;700&display=swap');

/* ── Tokens ─────────────────────────────────────────────── */
:root {
  /* MUI palette */
  --primary:        #1976D2;
  --primary-dark:   #1565C0;
  --primary-light:  #E3F2FD;
  --primary-text:   #0D47A1;

  --error:          #D32F2F;
  --error-light:    #FFEBEE;
  --warning:        #ED6C02;
  --warning-light:  #FFF3E0;
  --success:        #2E7D32;
  --success-light:  #E8F5E9;
  --info:           #0288D1;
  --info-light:     #E1F5FE;

  /* Neutrals */
  --bg:             #F5F5F5;
  --surface:        #FFFFFF;
  --surface-raised: #FFFFFF;
  --divider:        rgba(0,0,0,.12);
  --divider-strong: rgba(0,0,0,.20);

  /* Text */
  --text-primary:   rgba(0,0,0,.87);
  --text-secondary: rgba(0,0,0,.60);
  --text-disabled:  rgba(0,0,0,.38);

  /* Elevation (MUI dp values) */
  --shadow-1:  0 1px 3px rgba(0,0,0,.12), 0 1px 2px rgba(0,0,0,.08);
  --shadow-2:  0 3px 6px rgba(0,0,0,.10), 0 2px 4px rgba(0,0,0,.08);
  --shadow-4:  0 4px 12px rgba(0,0,0,.12), 0 2px 6px rgba(0,0,0,.08);
  --shadow-8:  0 8px 24px rgba(0,0,0,.12), 0 4px 8px rgba(0,0,0,.08);

  /* Shape */
  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;

  /* Spacing (8px grid) */
  --sp1: 8px;
  --sp2: 16px;
  --sp3: 24px;
  --sp4: 32px;
  --sp5: 40px;
  --sp6: 48px;

  /* Typography */
  --font: 'Roboto', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'Roboto Mono', monospace;
}

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

/* ── Base ────────────────────────────────────────────────── */
html { font-size: 16px; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

/* ── Header / AppBar ─────────────────────────────────────── */
.appbar {
  position: sticky;
  top: 0;
  z-index: 200;
  background: var(--primary);
  box-shadow: var(--shadow-4);
  height: 64px;
  display: flex;
  align-items: center;
  padding: 0 var(--sp3);
  gap: var(--sp2);
}

@media (max-width: 600px) {
  .appbar { height: 56px; padding: 0 var(--sp2); }
}

/* Logo */
.logo-wrap {
  display: flex;
  align-items: center;
  gap: var(--sp1) + 4px;
  text-decoration: none;
  color: #fff;
  gap: 12px;
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: rgba(255,255,255,.18);
  border-radius: var(--radius-xs);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.5px;
  color: #fff;
  flex-shrink: 0;
}

.logo-img { height: 36px; width: auto; }

.logo-text {
  font-size: 20px;
  font-weight: 500;
  color: #fff;
  letter-spacing: .15px;
  line-height: 1.2;
}

.logo-sub {
  font-size: 11px;
  color: rgba(255,255,255,.70);
  letter-spacing: .4px;
}

/* ── Lang Dropdown ───────────────────────────────────────── */
.lang-switcher {
  margin-left: auto;
  position: relative;
  flex-shrink: 0;
}

.lang-selected {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: var(--radius-xs);
  font-size: 14px;
  font-weight: 500;
  font-family: var(--font);
  color: #fff;
  border: 1px solid rgba(255,255,255,.30);
  background: rgba(255,255,255,.10);
  cursor: pointer;
  user-select: none;
  white-space: nowrap;
  transition: background .15s;
}

.lang-selected:hover { background: rgba(255,255,255,.20); }

.lang-flag { font-size: 18px; line-height: 1; }

.arrow {
  font-size: 10px;
  color: rgba(255,255,255,.70);
  margin-left: 2px;
  transition: transform .2s;
}

.lang-switcher.open .arrow { transform: rotate(180deg); }

.lang-dropdown {
  display: none;
  position: absolute;
  right: 0;
  top: calc(100% + 8px);
  background: var(--surface);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-8);
  min-width: 160px;
  overflow: hidden;
  z-index: 300;
}

.lang-switcher.open .lang-dropdown { display: block; }

.lang-option {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 16px;
  font-size: 14px;
  font-weight: 400;
  color: var(--text-primary);
  text-decoration: none;
  transition: background .1s;
}

.lang-option:hover { background: rgba(25,118,210,.06); }

.lang-option.active {
  color: var(--primary);
  font-weight: 500;
  background: var(--primary-light);
}

/* ── Main Container ──────────────────────────────────────── */
.container {
  max-width: 800px;
  margin: 0 auto;
  padding: var(--sp5) var(--sp3) var(--sp6);
}

@media (max-width: 600px) {
  .container { padding: var(--sp3) var(--sp2) var(--sp5); }
}

/* ── Page Hero ───────────────────────────────────────────── */
.page-hero { margin-bottom: var(--sp4); }

.page-title {
  font-size: 34px;
  font-weight: 700;
  letter-spacing: -.5px;
  color: var(--text-primary);
  margin-bottom: 8px;
  line-height: 1.2;
}

.page-subtitle {
  font-size: 16px;
  color: var(--text-secondary);
  line-height: 1.6;
}

@media (max-width: 600px) {
  .page-title { font-size: 26px; }
  .page-subtitle { font-size: 15px; }
}

@media (max-width: 400px) {
  .page-title { font-size: 22px; }
}

/* ── Paper / Card ────────────────────────────────────────── */
.paper {
  background: var(--surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-2);
  padding: var(--sp3);
  margin-bottom: var(--sp3);
}

/* ── Textarea ────────────────────────────────────────────── */
.field-wrap { position: relative; }

.field-label {
  display: block;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .4px;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

textarea {
  width: 100%;
  min-height: 160px;
  resize: vertical;
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg);
  border: 1px solid var(--divider-strong);
  border-radius: var(--radius-xs);
  padding: 14px 16px;
  outline: none;
  transition: border-color .15s, box-shadow .15s;
}

textarea:hover { border-color: rgba(0,0,0,.42); }

textarea:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(25,118,210,.15);
  background: #fff;
}

/* ── Form Footer ─────────────────────────────────────────── */
.form-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: var(--sp2);
  gap: 12px;
  flex-wrap: wrap;
}

.char-count {
  font-size: 13px;
  color: var(--text-disabled);
  letter-spacing: .2px;
}

/* ── Button ──────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--primary);
  color: #fff;
  border: none;
  padding: 10px 28px;
  border-radius: var(--radius-xs);
  font-family: var(--font);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: .5px;
  cursor: pointer;
  box-shadow: var(--shadow-2);
  transition: background .15s, box-shadow .15s, transform .1s;
  white-space: nowrap;
}

.btn:hover {
  background: var(--primary-dark);
  box-shadow: var(--shadow-4);
}

.btn:active { transform: scale(.98); box-shadow: var(--shadow-1); }

/* ── Error Box ───────────────────────────────────────────── */
.error-box {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  background: var(--error-light);
  border-left: 4px solid var(--error);
  border-radius: 0 var(--radius-xs) var(--radius-xs) 0;
  padding: 12px 16px;
  color: var(--error);
  font-size: 14px;
  margin-top: var(--sp2);
  line-height: 1.5;
}

/* ── Results section ─────────────────────────────────────── */
.results { animation: fadeUp .3s ease; }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ── Score Grid ──────────────────────────────────────────── */
.score-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--sp2);
  margin-bottom: var(--sp3);
}

@media (max-width: 640px) {
  .score-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
}

@media (max-width: 340px) {
  .score-grid { grid-template-columns: 1fr; }
}

.score-card {
  background: var(--surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-2);
  padding: 20px 16px;
  text-align: center;
  transition: box-shadow .2s;
}

.score-card:hover { box-shadow: var(--shadow-4); }

.score-label {
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .8px;
  text-transform: uppercase;
  color: var(--text-disabled);
  margin-bottom: 10px;
}

.score-value {
  font-size: 36px;
  font-weight: 700;
  letter-spacing: -1px;
  line-height: 1;
}

.score-sub {
  font-size: 15px;
  font-weight: 500;
  margin-top: 6px;
  line-height: 1.3;
}

/* Semantic colors */
.c-danger  { color: var(--error); }
.c-warning { color: var(--warning); }
.c-success { color: var(--success); }
.c-info    { color: var(--info); }

/* ── Score Bar ───────────────────────────────────────────── */
.score-bar-wrap {
  background: var(--surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-2);
  padding: var(--sp3);
  margin-bottom: var(--sp3);
}

.score-bar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.score-bar-title {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  letter-spacing: .2px;
}

.score-bar-pct {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: -.3px;
}

.score-bar-track {
  height: 6px;
  background: rgba(0,0,0,.08);
  border-radius: 3px;
  overflow: hidden;
  margin-bottom: 10px;
}

.score-bar-fill {
  height: 100%;
  border-radius: 3px;
  transition: width .6s cubic-bezier(.4,0,.2,1);
}

.fill-danger  { background: var(--error); }
.fill-warning { background: var(--warning); }
.fill-success { background: var(--success); }
.fill-info    { background: var(--info); }

.score-bar-labels {
  display: flex;
  justify-content: space-between;
  font-size: 11px;
  color: var(--text-disabled);
  letter-spacing: .3px;
}

/* ── Signals ─────────────────────────────────────────────── */
.signals-paper {
  background: var(--surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-2);
  overflow: hidden;
  margin-bottom: var(--sp3);
}

.signals-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px var(--sp3);
  border-bottom: 1px solid var(--divider);
}

.signals-title {
  font-size: 14px;
  font-weight: 500;
  letter-spacing: .1px;
  color: var(--text-secondary);
}

.signals-count {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--primary-light);
  color: var(--primary-text);
  font-size: 12px;
  font-weight: 700;
}

.signals-list { padding: 8px 0; }

.signal {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  padding: 11px var(--sp3);
  font-size: 14px;
  line-height: 1.5;
  border-bottom: 1px solid var(--divider);
  transition: background .1s;
}

.signal:last-child { border-bottom: none; }
.signal:hover { background: rgba(0,0,0,.02); }

.signal-icon {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  margin-top: 1px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  font-weight: 700;
}

.signal.danger  .signal-icon { background: var(--error-light);   color: var(--error); }
.signal.warning .signal-icon { background: var(--warning-light); color: var(--warning); }
.signal.success .signal-icon { background: var(--success-light); color: var(--success); }
.signal.info    .signal-icon { background: var(--info-light);    color: var(--info); }

.signal.danger  { color: var(--text-primary); }
.signal.warning { color: var(--text-primary); }
.signal.success { color: var(--text-primary); }
.signal.info    { color: var(--text-primary); }

/* ── Stats Row ───────────────────────────────────────────── */
.stats-row {
  display: flex;
  gap: var(--sp3);
  flex-wrap: wrap;
  padding: 14px var(--sp3);
  background: rgba(0,0,0,.02);
  border-top: 1px solid var(--divider);
}

.stat {
  display: flex;
  align-items: baseline;
  gap: 5px;
  font-size: 12px;
  color: var(--text-secondary);
  letter-spacing: .2px;
}

.stat-val {
  font-size: 14px;
  font-weight: 700;
  color: var(--text-primary);
}

/* ── Disclaimer ──────────────────────────────────────────── */
.disclaimer {
  text-align: center;
  font-size: 12px;
  color: var(--text-disabled);
  line-height: 1.6;
  padding: 0 var(--sp2);
  margin-top: var(--sp2);
}

/* ── Divider ─────────────────────────────────────────────── */
hr {
  border: none;
  border-top: 1px solid var(--divider);
  margin: var(--sp3) 0;
}

/* ── Scrollbar (Chrome/Edge) ─────────────────────────────── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: rgba(0,0,0,.20); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: rgba(0,0,0,.35); }

/* ── About + FAQ Section ─────────────────────────────────── */
.info-section {
  margin-top: var(--sp5);
}

.info-paper {
  background: var(--surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-2);
  overflow: hidden;
  margin-bottom: var(--sp3);
}

/* About block */
.about-block {
  padding: var(--sp3) var(--sp3) var(--sp2);
  border-bottom: 1px solid var(--divider);
}

.about-block h2 {
  font-size: 20px;
  font-weight: 500;
  letter-spacing: .15px;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.about-block p {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* Rules grid */
.rules-block {
  padding: var(--sp3);
  border-bottom: 1px solid var(--divider);
}

.rules-block h3 {
  font-size: 13px;
  font-weight: 500;
  letter-spacing: .8px;
  text-transform: uppercase;
  color: var(--text-disabled);
  margin-bottom: var(--sp2);
}

.rules-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

@media (max-width: 680px) {
  .rules-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 440px) {
  .rules-grid { grid-template-columns: 1fr; }
}

.rule-card {
  background: var(--bg);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
  border-left: 3px solid var(--primary);
}

.rule-card-title {
  font-size: 13px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.rule-card-text {
  font-size: 12px;
  color: var(--text-secondary);
  line-height: 1.55;
}

/* FAQ accordion */
.faq-block {
  padding: var(--sp3) var(--sp3) var(--sp2);
}

.faq-block h3 {
  font-size: 13px;
  font-weight: 500;
  letter-spacing: .8px;
  text-transform: uppercase;
  color: var(--text-disabled);
  margin-bottom: var(--sp2);
}

.faq-item {
  border-bottom: 1px solid var(--divider);
}

.faq-item:last-child { border-bottom: none; }

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 0;
  background: none;
  border: none;
  font-family: var(--font);
  font-size: 15px;
  font-weight: 500;
  color: var(--text-primary);
  cursor: pointer;
  text-align: left;
  transition: color .15s;
}

.faq-question:hover { color: var(--primary); }

.faq-icon {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--primary-light);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 400;
  line-height: 1;
  transition: background .15s, transform .2s;
}

.faq-item.open .faq-icon {
  background: var(--primary);
  color: #fff;
  transform: rotate(45deg);
}

.faq-answer {
  display: none;
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
  padding-bottom: 14px;
}

.faq-item.open .faq-answer { display: block; }