:root {
  color-scheme: light dark;
  --bg: #f5f6f8;
  --card: #ffffff;
  --text: #1c1e21;
  --muted: #6b7280;
  --border: #e2e4e9;
  --accent: #2f5597;
  --accent-text: #ffffff;
  --danger: #c0392b;
  --input-bg: #fff9e6;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #15171a;
    --card: #1f2226;
    --text: #e8e9ec;
    --muted: #9aa0aa;
    --border: #33373d;
    --accent: #5b8def;
    --accent-text: #0b1220;
    --danger: #ff6b5e;
    --input-bg: #2a2718;
  }
}

/* Manual theme toggle overrides system preference in both directions. */
:root[data-theme="light"] {
  --bg: #f5f6f8; --card: #ffffff; --text: #1c1e21; --muted: #6b7280;
  --border: #e2e4e9; --accent: #2f5597; --accent-text: #ffffff;
  --danger: #c0392b; --input-bg: #fff9e6;
}
:root[data-theme="dark"] {
  --bg: #15171a; --card: #1f2226; --text: #e8e9ec; --muted: #9aa0aa;
  --border: #33373d; --accent: #5b8def; --accent-text: #0b1220;
  --danger: #ff6b5e; --input-bg: #2a2718;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  width: 100%;
  overflow-x: hidden;
  font-family: Arial, Helvetica, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.page-center {
  min-height: 100vh;
  min-height: 100dvh; /* avoids the layout jump caused by 100vh when a mobile browser's address bar shows/hides */
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  padding-top: 64px; /* clears the fixed corner-controls bar on short/landscape screens */
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 24px;
  width: 100%;
  max-width: 360px;
}

.card h1 {
  font-size: 1.25rem;
  margin: 0 0 16px;
}

label {
  display: block;
  font-size: 0.85rem;
  color: var(--muted);
  margin: 12px 0 4px;
}

input, select, textarea {
  width: 100%;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--card);
  color: var(--text);
  /* iOS Safari auto-zooms the page on focus for any field under 16px — that
     zoom-in/zoom-out on tap is the "page jumping" this is fixing. */
  font-size: 16px;
}

/* Selects inside table cells (group picker, status pickers) get a floor
   width so the auto table-layout algorithm doesn't squeeze them down to the
   point where the selected option's text gets clipped. */
td select {
  min-width: 130px;
  width: auto;
}

button {
  cursor: pointer;
  border: none;
  border-radius: 6px;
  padding: 9px 14px;
  font-size: 0.9rem;
  background: var(--accent);
  color: var(--accent-text);
}

button.secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}

button.danger {
  background: var(--danger);
  color: #fff;
}

.error-text {
  color: var(--danger);
  font-size: 0.85rem;
  min-height: 1.2em;
  margin-top: 8px;
}

.submit-row {
  margin-top: 16px;
}
.submit-row button { width: 100%; }

/* ---- app shell ---- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  background: var(--card);
  border-bottom: 1px solid var(--border);
}
.topbar .user-name { font-weight: bold; }
.topbar-left { display: flex; align-items: center; gap: 12px; }
.topbar-right { display: flex; align-items: center; gap: 10px; }
.brand { font-weight: bold; color: var(--accent); white-space: nowrap; }

.corner-controls {
  position: fixed;
  top: 14px;
  right: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
  z-index: 10;
}

.lang-switcher { display: flex; gap: 2px; }
.lang-flag {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 2px 7px;
  font-size: 0.8rem;
  font-weight: 600;
  line-height: 1.6;
  color: var(--muted);
}
.lang-flag.active { color: var(--accent-text); background: var(--accent); border-color: var(--accent); }

.theme-toggle {
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 4px 8px;
  font-size: 1rem;
}

.stats-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  margin: 6px 0;
  font-size: 0.9rem;
  display: flex;
  flex-wrap: wrap;
  gap: 4px 18px;
}
.stats-card b { color: var(--accent); }

.trial-contact-form {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin-top: 6px;
  max-width: 220px;
}
.trial-contact-form input { font-size: 0.85rem; padding: 5px 8px; }

.lesson-picker {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}
.lesson-picker .lesson-btn.active {
  background: var(--accent);
  color: var(--accent-text);
  border-color: var(--accent);
}

.tabs {
  display: flex;
  overflow-x: auto;
  background: var(--card);
  border-bottom: 1px solid var(--border);
}
.tabs button {
  background: transparent;
  color: var(--muted);
  border-radius: 0;
  padding: 12px 16px;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
}
.tabs button.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
  font-weight: bold;
}

main {
  padding: 16px;
  max-width: 1100px;
  margin: 0 auto;
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: end;
  margin-bottom: 14px;
}
.toolbar .field { display: flex; flex-direction: column; }
.toolbar label { margin: 0 0 4px; }

/* Wraps every <table> — on screens too narrow for the full table (but wide
   enough to still be above the 640px card-view breakpoint, e.g. tablets),
   it scrolls internally instead of stretching the whole page horizontally. */
.table-wrap {
  width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

table {
  width: 100%;
  border-collapse: collapse;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}
th, td {
  text-align: left;
  padding: 8px 10px;
  border-bottom: 1px solid var(--border);
  font-size: 0.9rem;
}
th { color: var(--muted); font-weight: 600; }

.input-cell { background: var(--input-bg); }

.form-inline {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px;
  margin-bottom: 14px;
}
.form-inline .field { display: flex; flex-direction: column; min-width: 140px; flex: 1; }
.form-inline label { margin: 0 0 4px; }

.hidden { display: none !important; }

@media (max-width: 640px) {
  table, thead, tbody, th, td, tr { display: block; }
  thead { display: none; }
  tr {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 8px;
    margin-bottom: 10px;
    padding: 6px 0;
  }
  td {
    border: none;
    display: flex;
    justify-content: space-between;
    gap: 10px;
  }
  td::before {
    content: attr(data-label);
    color: var(--muted);
    font-weight: 600;
  }

  /* Topbar wraps onto a second line instead of clipping/overlapping on
     narrow phones (brand + user name + lang switcher + theme + logout all
     competing for one row). */
  .topbar { flex-wrap: wrap; row-gap: 8px; }
  .topbar-left, .topbar-right { flex-wrap: wrap; row-gap: 6px; }

  main { padding: 12px; }

  /* Full-width stacked fields instead of a tight multi-column squeeze. */
  .toolbar .field, .form-inline .field { min-width: 0; flex: 1 1 100%; }

  .corner-controls { gap: 6px; }
  .lang-flag { padding: 2px 5px; font-size: 0.72rem; }
}