:root {
  --primary: #1a202c;
  --accent: #fbbf24;
  --bg: #f9fafb;
  --card: #fff;
  --border: #e5e7eb;
  --radius: 12px;
  --shadow: 0 2px 8px rgba(0,0,0,0.07);
}
body {
  margin: 0; font-family: 'Segoe UI', Arial, sans-serif; background: var(--bg); color: var(--primary); min-height: 100vh;
}
header {
  background: var(--primary); color: #fff; padding: 0; position: relative;
}
.banner {
  width: 100%; height: 160px; overflow: hidden; display: flex; align-items: center; justify-content: center; background: #1a202c;
}
.banner img {
  width: 100%; height: 100%; object-fit: cover; object-position: center; max-width: none; max-height: none; border-radius: 0; box-shadow: none;
}
.lang-switch {
  position: absolute; right: 1rem; top: 1rem; z-index: 10;
}
.lang-switch button {
  background: var(--accent); color: var(--primary); border: none; border-radius: var(--radius); padding: 0.4em 1em; margin-left: 0.5em; font-weight: bold; cursor: pointer;
}
main { max-width: 1100px; margin: 2rem auto; padding: 0 1rem; }
.section {
  margin-bottom: 2.5rem;
  background: #fffbe8;
  border-radius: var(--radius);
  box-shadow: 0 2px 12px rgba(251,191,36,0.08);
  border: 1.5px solid #ffe082;
  transition: box-shadow 0.2s, border 0.2s, opacity 0.3s;
  overflow: hidden;
  display: block;
}
.section.open {
  box-shadow: 0 4px 24px rgba(251,191,36,0.16);
  border-color: #fbbf24;
}
.section-title {
  font-size: 1.01rem;
  font-weight: 600;
  color: var(--primary);
  background: linear-gradient(90deg, #fffbe8 0%, #fffde4 100%);
  padding: 0.55em 1.1em 0.55em 2em;
  border-radius: var(--radius) var(--radius) 0 0;
  box-shadow: none;
  display: flex;
  align-items: center;
  cursor: pointer;
  position: relative;
  user-select: none;
  border-bottom: 1px solid #ffe082;
  margin: 0;
  letter-spacing: 0.01em;
  min-height: 0;
  transition: background 0.18s, font-size 0.18s;
}
.section-title::before {
  content: '\25B6';
  font-size: 1em;
  margin-right: 0.7em;
  color: #b08900;
  transition: transform 0.2s;
  position: absolute;
  left: 0.7em;
  top: 50%;
  transform: translateY(-50%) rotate(0deg);
}
.section.open .section-title::before {
  transform: translateY(-50%) rotate(90deg);
}
.slider-panel {
  width: 100%;
  flex-shrink: 0;
  box-sizing: border-box;
  padding: 0;
  background: #fffbe8;
  min-height: 120px;
  position: relative;
}
.slider-panel .questions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  padding: 1.2em 1.5em 1.5em 1.5em;
  background: none;
  transition: max-height 0.3s, opacity 0.3s;
}
.questions-grid,
.slider-panel > .questions-grid {
  display: grid !important;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)) !important;
  gap: 1rem !important;
  padding: 1.2em 1.5em 1.5em 1.5em !important;
  background: none;
  transition: max-height 0.3s, opacity 0.3s;
}
.slider-panel:not(:first-child) .questions-grid {
  display: block !important;
  grid-template-columns: none !important;
  gap: 0 !important;
  padding: 0 !important;
}
.questions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  padding: 1.2em 1.5em 1.5em 1.5em;
  background: none;
  transition: max-height 0.3s, opacity 0.3s;
}
.section:not(.open) .questions-grid {
  display: none;
}
.question-card {
  background: var(--card);
  border: 1px solid #f3e9c7;
  border-radius: var(--radius);
  box-shadow: 0 2px 8px rgba(251,191,36,0.10), 0 1.5px 8px rgba(30,32,44,0.04);
  padding: 1.1rem 1.1rem 1rem 1.1rem;
  cursor: pointer;
  transition: box-shadow 0.22s, border-color 0.18s, transform 0.13s, opacity 0.35s cubic-bezier(.77,0,.18,1);
  position: relative;
}
.question-card.solved {
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.35s cubic-bezier(.77,0,.18,1);
}
.question-card.disabled {
  opacity: 0.5;
  pointer-events: none;
  filter: grayscale(0.5);
}
.question-card.disabled .question-check,
.question-card.disabled .hint-btn {
  pointer-events: none;
  opacity: 0.3;
}
.question-check {
  position: absolute;
  top: 10px;
  right: 10px;
  width: 32px;
  height: 32px;
  background: #fffbe8;
  border: 2px solid #ffe082;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 3;
  box-shadow: 0 1px 4px rgba(251,191,36,0.10);
  transition: background 0.15s, border 0.15s;
  color: #fff;
}
.question-check svg {
  width: 18px; height: 18px;
  display: block;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.18s;
}
.question-check.checked {
  background: linear-gradient(135deg,#fbbf24 60%,#ffe082 100%);
  border: 2px solid #fbbf24;
}
.question-check.checked svg {
  opacity: 1;
  stroke: #fff;
}
.question-check:not(.checked) svg {
  opacity: 0.2;
  stroke: #b08900;
}
.hint-btn {
  position: absolute;
  right: 10px;
  bottom: 10px;
  display: block;
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  width: 22px;
  height: 22px;
  margin: 0;
  z-index: 2;
}
.section.hidden {
  display: none !important;
  opacity: 0;
  pointer-events: none;
}
#modal {
  display: none;
  position: fixed;
  z-index: 1000;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(30,32,44,0.55);
  align-items: center;
  justify-content: center;
}
#modal-content {
  background: #fff;
  max-width: 540px;
  width: 96vw;
  max-height: 92vh;
  overflow: auto;
  border-radius: 16px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.18);
  padding: 2rem 1.2rem 1.2rem 1.2rem;
  position: relative;
  word-break: break-word;
  white-space: normal;
  display: block;
}
#modal-close {
  position: absolute;
  top: 0.7rem;
  right: 1.1rem;
  background: var(--accent);
  color: var(--primary);
  border: none;
  border-radius: 50%;
  width: 2.2em;
  height: 2.2em;
  font-size: 1.3em;
  cursor: pointer;
}
.search-row {
  width: 100%;
  max-width: 600px;
  margin: 0.7em auto 0.2em auto;
  display: flex;
  justify-content: center;
}
.search-row input {
  width: 100%;
  max-width: 420px;
  padding: 0.48em 0.9em;
  border-radius: 8px;
  border: 1.5px solid #ffe082;
  font-size: 0.97em;
  outline: none;
  box-shadow: 0 1px 4px rgba(251,191,36,0.06);
}
#progress-bar-row {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: none;
  margin: 0;
  padding: 0.2em 0 0.2em 0;
}
#progress-bar-container {
  flex: 1;
  max-width: 720px;
  background: none;
  padding: 0;
  margin: 0;
}
#progress-bar-container > div {
  width: 100%;
  height: 22px;
  background: #e5e7eb;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 1px 4px rgba(0,0,0,0.04);
  position: relative;
  display: flex;
  align-items: center;
}
#progress-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg,#fbbf24 0%,#ffe082 100%);
  transition: width 0.4s;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  font-weight: 600;
  font-size: 1em;
  color: #222;
  letter-spacing: 0.01em;
}
#progress-reset {
  margin-left: 16px;
  background: #fffbe8;
  border: 1.5px solid #ffe082;
  border-radius: 50%;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1.1em;
  color: #b08900;
  box-shadow: 0 1px 4px rgba(251,191,36,0.08);
  transition: background 0.15s;
  z-index: 2;
}
.loading-msg {
  text-align: center;
  margin-top: 2em;
  color: #888;
}
footer {
  width: 100%;
  background: #f9fafb;
  border-top: 1.5px solid #ffe082;
  margin-top: 2.5em;
  padding: 1.2em 0 1.2em 0;
  text-align: center;
  font-size: 1em;
  color: #b08900;
  letter-spacing: 0.01em;
}
.footer-row {
  margin-bottom: 0.3em;
}
.footer-row a {
  color: #b08900;
  text-decoration: underline;
  font-weight: 600;
}
.level-info-panel {
  background: #f3f4f6 !important; /* Tailwind gray-100 */
  border: 2px solid #d1d5db !important; /* Tailwind gray-300 */
  border-radius: 14px;
  box-shadow: 0 2px 16px rgba(30,32,44,0.08);
  margin: 2.2em 0 1.2em 0;
  padding: 1.3em 1.2em 1.1em 1.2em;
  text-align: left;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
}