/* ══════════════════════════════════════════
   TrainEnglish — Terra Design System
   Pure CSS, no @import, no dark mode
══════════════════════════════════════════ */

/* ── Custom Properties ── */
:root {
  --bg:             #faf6f0;
  --surface:        #fffcf8;
  --surface2:       #f5ece0;
  --border:         #e7ddd0;
  --border2:        #e7e0d8;
  --accent:         #b45309;
  --accent-light:   #fef3c7;
  --accent-shadow:  rgba(180, 83, 9, 0.25);
  --success:        #065f46;
  --error:          #b91c1c;
  --warning:        #d97706;
  --text:           #1c1917;
  --text2:          #44403c;
  --subtext:        #a8887a;
  --muted:          #d6c5b4;
  --topbar-h:       58px;
  --nav-h:          68px;
}

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

/* ── Base Typography ── */
html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: 'Plus Jakarta Sans', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  min-height: 100vh;
}

/* ── Page Content Wrapper ── */
.page-content {
  padding-top: calc(var(--topbar-h) + 16px);
  padding-bottom: calc(var(--nav-h) + 16px);
  padding-left: 16px;
  padding-right: 16px;
  max-width: 480px;
  margin: 0 auto;
}

@media (min-width: 640px) {
  .page-content {
    max-width: 640px;
  }
}

/* ── Topbar ── */
.topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--topbar-h);
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
}

.topbar-title {
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
}

.topbar-logo {
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.3px;
  text-decoration: none;
}

.topbar-logo span {
  color: var(--accent);
}

.topbar-icon {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  color: var(--subtext);
  text-decoration: none;
  font-size: 18px;
  background: transparent;
  border: none;
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
}

.topbar-icon:hover {
  background: var(--surface2);
  color: var(--text);
}

.topbar-back {
  font-size: 20px;
  color: var(--text2);
  text-decoration: none;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 10px;
  transition: background 0.2s;
}

.topbar-back:hover {
  background: var(--surface2);
}

/* ── Bottom Nav ── */
.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: var(--nav-h);
  background: var(--surface);
  border-top: 1px solid var(--border);
  display: flex;
  z-index: 100;
}

.nav-item {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 3px;
  text-decoration: none;
  color: var(--subtext);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.04em;
  transition: color 0.2s;
}

.nav-item.active {
  color: var(--accent);
}

.nav-icon {
  font-size: 20px;
  line-height: 1;
}

/* ── Cards ── */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 20px;
  box-shadow: 0 2px 8px rgba(180, 83, 9, 0.06);
}

.card + .card {
  margin-top: 12px;
}

.card-label {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--subtext);
  text-transform: uppercase;
  margin-bottom: 10px;
}

/* ── Buttons ── */
.btn {
  display: block;
  width: 100%;
  padding: 14px;
  border: none;
  border-radius: 12px;
  font-family: inherit;
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  text-align: center;
  text-decoration: none;
  transition: box-shadow 0.2s, opacity 0.2s, background 0.2s;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 4px 14px var(--accent-shadow);
}

.btn-primary:hover {
  box-shadow: 0 6px 20px rgba(180, 83, 9, 0.35);
}

.btn-primary:active {
  opacity: 0.9;
}

.btn-secondary {
  background: var(--surface2);
  color: var(--text2);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  background: var(--border);
}

.btn-ghost {
  background: transparent;
  color: var(--accent);
  border: 1px solid var(--accent);
}

.btn-ghost:hover {
  background: var(--accent-light);
}

.btn-danger {
  background: transparent;
  color: var(--error);
  border: 1px solid var(--error);
}

.btn-danger:hover {
  background: #fef2f2;
}

/* ── Badge ── */
.badge {
  display: inline-block;
  padding: 4px 10px;
  background: var(--accent-light);
  color: var(--accent);
  border-radius: 6px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.04em;
}

/* ── Progress Bar ── */
.progress-bar {
  height: 6px;
  background: var(--surface2);
  border-radius: 4px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 4px;
  transition: width 0.3s ease;
}

/* ── Calendar Grid ── */
.cal-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 5px;
}

.cal-day {
  aspect-ratio: 1;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 10px;
  font-weight: 600;
  color: var(--muted);
  background: var(--surface2);
}

.cal-day.done {
  background: #fde8d8;
  color: var(--accent);
}

.cal-day.today {
  background: var(--accent);
  color: #fff;
}

.cal-day.future {
  opacity: 0.35;
}

/* ── Topic Row ── */
.topic-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  border-radius: 10px;
  margin-bottom: 6px;
}

.topic-row:last-child {
  margin-bottom: 0;
}

.topic-name {
  font-size: 13px;
  font-weight: 600;
  color: var(--text2);
}

.topic-pct {
  font-size: 12px;
  font-weight: 700;
}

.pct-good { color: var(--success); }
.pct-mid  { color: var(--warning); }
.pct-bad  { color: var(--error); }

/* ── Inputs ── */
.input-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 16px;
}

label {
  font-size: 12px;
  font-weight: 600;
  color: var(--text2);
}

input[type="email"],
input[type="password"],
input[type="text"],
textarea {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: 10px;
  font-family: inherit;
  font-size: 14px;
  background: var(--surface);
  color: var(--text);
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}

input[type="email"]:focus,
input[type="password"]:focus,
input[type="text"]:focus,
textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(180, 83, 9, 0.12);
}

textarea {
  resize: vertical;
  min-height: 120px;
  line-height: 1.6;
}

/* ── Divider ── */
.divider {
  height: 1px;
  background: var(--border);
  margin: 20px 0;
}

/* ── Section Title ── */
.section-title {
  font-size: 13px;
  font-weight: 700;
  color: var(--text2);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 12px;
}

/* ── Chip ── */
.chip {
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 11px;
  font-weight: 600;
  border: 1px solid var(--border);
  color: var(--subtext);
  background: var(--surface2);
  cursor: pointer;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
  user-select: none;
}

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

.chip:hover:not(.active) {
  background: var(--border);
  color: var(--text2);
}

/* ── Alerts ── */
.alert {
  padding: 12px 16px;
  border-radius: 10px;
  font-size: 13px;
  font-weight: 500;
  border: 1px solid;
}

.alert-success {
  background: #ecfdf5;
  border-color: #a7f3d0;
  color: var(--success);
}

.alert-error {
  background: #fef2f2;
  border-color: #fecaca;
  color: var(--error);
}

.alert-warning {
  background: #fffbeb;
  border-color: #fde68a;
  color: var(--warning);
}

/* ── Accordion ── */
.accordion-item {
  border: 1px solid var(--border);
  border-radius: 12px;
  margin-bottom: 8px;
  overflow: hidden;
}

.accordion-header {
  padding: 14px 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  font-weight: 600;
  font-size: 14px;
  background: var(--surface);
  user-select: none;
  transition: background 0.2s;
}

.accordion-header:hover {
  background: var(--surface2);
}

.accordion-arrow {
  font-size: 12px;
  color: var(--subtext);
  transition: transform 0.3s ease;
}

.accordion-body {
  padding: 0 16px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
  background: var(--surface);
  font-size: 14px;
  color: var(--text2);
  line-height: 1.7;
}

.accordion-body.open {
  max-height: 2000px;
  padding: 16px;
}

/* ── Stat Cards ── */
.stat-card {
  text-align: center;
  padding: 20px;
}

.stat-num {
  font-size: 36px;
  font-weight: 800;
  color: var(--accent);
  line-height: 1;
  letter-spacing: -1.5px;
}

.stat-label {
  font-size: 11px;
  color: var(--subtext);
  margin-top: 4px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* ── Tags ── */
.tag {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 600;
  background: var(--surface2);
  color: var(--subtext);
}

/* ── Chips row ── */
.chips-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}

/* ── Stats accuracy bar ── */
.accuracy-row {
  margin-bottom: 14px;
}

.accuracy-label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 6px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text2);
}

.accuracy-pct {
  font-size: 12px;
  font-weight: 700;
}

/* ── Day counter display ── */
.day-big {
  font-size: 52px;
  font-weight: 800;
  color: var(--text);
  line-height: 1;
  letter-spacing: -2px;
}

.day-sub {
  font-size: 13px;
  color: var(--subtext);
  margin-top: 4px;
}

.streak-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 16px;
}

.streak-num {
  font-size: 26px;
  font-weight: 700;
  color: var(--accent);
}

.streak-label {
  font-size: 12px;
  color: var(--subtext);
  line-height: 1.4;
}

/* ── FAB ── */
.fab {
  position: fixed;
  bottom: calc(var(--nav-h) + 16px);
  right: 16px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 16px;
  padding: 12px 18px;
  font-family: inherit;
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 4px 16px var(--accent-shadow);
  z-index: 90;
  transition: box-shadow 0.2s;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 6px;
}

.fab:hover {
  box-shadow: 0 6px 24px rgba(180, 83, 9, 0.4);
}

/* ── Session specific ── */
.session-topbar {
  position: sticky;
  top: 0;
  left: 0;
  right: 0;
  height: var(--topbar-h);
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
}

.session-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
  flex: 1;
  text-align: center;
}

.session-timer {
  font-size: 13px;
  font-weight: 600;
  color: var(--subtext);
  min-width: 40px;
  text-align: right;
}

/* ── Exercise card ── */
.exercise-part {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--subtext);
  text-transform: uppercase;
  margin-bottom: 8px;
}

.exercise-question {
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
  line-height: 1.5;
  margin-bottom: 18px;
}

.option-btn {
  display: block;
  width: 100%;
  padding: 13px 16px;
  background: var(--surface2);
  border: 2px solid var(--border);
  border-radius: 10px;
  font-family: inherit;
  font-size: 14px;
  font-weight: 500;
  color: var(--text2);
  cursor: pointer;
  text-align: left;
  margin-bottom: 8px;
  transition: background 0.15s, border-color 0.15s;
}

.option-btn:last-child {
  margin-bottom: 0;
}

.option-btn:hover:not(:disabled) {
  background: var(--accent-light);
  border-color: var(--accent);
  color: var(--text);
}

.option-btn.selected {
  background: var(--accent-light);
  border-color: var(--accent);
  color: var(--text);
}

.option-btn.correct {
  background: #ecfdf5;
  border-color: #6ee7b7;
  color: var(--success);
}

.option-btn.wrong {
  background: #fef2f2;
  border-color: #fca5a5;
  color: var(--error);
}

/* ── Feedback area ── */
.feedback {
  margin-top: 14px;
  padding: 14px;
  border-radius: 10px;
  font-size: 13px;
  line-height: 1.6;
  display: none;
}

.feedback.show {
  display: block;
}

.feedback.feedback-correct {
  background: #ecfdf5;
  border: 1px solid #a7f3d0;
  color: var(--success);
}

.feedback.feedback-wrong {
  background: #fef2f2;
  border: 1px solid #fecaca;
  color: var(--error);
}

/* ── Recap ── */
.recap-score {
  font-size: 48px;
  font-weight: 800;
  color: var(--accent);
  text-align: center;
  line-height: 1;
  letter-spacing: -2px;
}

.recap-label {
  text-align: center;
  font-size: 13px;
  color: var(--subtext);
  margin-top: 4px;
}

/* ── Settings form ── */
.form-section {
  margin-bottom: 24px;
}

.form-section-title {
  font-size: 12px;
  font-weight: 700;
  color: var(--subtext);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 14px;
}

/* ── Toast ── */
.toast {
  position: fixed;
  bottom: calc(var(--nav-h) + 12px);
  left: 50%;
  transform: translateX(-50%);
  background: var(--text);
  color: #fff;
  padding: 10px 20px;
  border-radius: 24px;
  font-size: 13px;
  font-weight: 600;
  z-index: 200;
  opacity: 0;
  transition: opacity 0.3s;
  white-space: nowrap;
  pointer-events: none;
}

.toast.show {
  opacity: 1;
}

/* ── Error log card ── */
.error-card {
  margin-bottom: 12px;
}

.error-card .badge {
  margin-bottom: 10px;
}

.error-question {
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 10px;
  line-height: 1.5;
}

.error-answers {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 10px;
}

.error-answer-row {
  font-size: 12px;
  color: var(--text2);
}

.error-answer-row span {
  font-weight: 600;
}

.error-explanation {
  font-size: 12px;
  color: var(--subtext);
  line-height: 1.6;
  padding-top: 10px;
  border-top: 1px solid var(--border);
}

/* ── Checkbox ── */
.checkbox-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
}

.checkbox-row input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--accent);
  cursor: pointer;
}

.checkbox-row label {
  font-size: 13px;
  font-weight: 500;
  color: var(--text2);
  cursor: pointer;
  margin: 0;
}

/* ── Utility ── */
.mt-8  { margin-top: 8px; }
.mt-12 { margin-top: 12px; }
.mt-16 { margin-top: 16px; }
.mt-20 { margin-top: 20px; }
.mt-24 { margin-top: 24px; }
.mb-8  { margin-bottom: 8px; }
.mb-12 { margin-bottom: 12px; }
.mb-16 { margin-bottom: 16px; }
.mb-20 { margin-bottom: 20px; }
.text-center { text-align: center; }
.text-muted { color: var(--subtext); font-size: 13px; }