/* ==========================================================================
   NORDIC TACTILE DESIGN (Outfit + Inter + Fira Code)
   ========================================================================== */
:root {
  --font-display: "Outfit", -apple-system, sans-serif;
  --font-sans: "Inter", -apple-system, sans-serif;
  --font-mono: "Fira Code", monospace;

  --bg: #f1f5f9;
  --bg-pattern: radial-gradient(rgba(79, 70, 229, 0.08) 1.5px, transparent 1.5px);
  --bg-pattern-size: 26px 26px;
  --bg-card: #ffffff;
  --bg-elevated: #f8fafc;
  --border: #e2e8f0;
  --border-strong: #4f46e5;
  --border-width: 1.5px;

  --text: #0f172a;
  --text-muted: #64748b;
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --primary-contrast: #ffffff;
  --accent-secondary: #10b981;

  --code-bg: #eef2ff;
  --code-text: #4338ca;
  --code-border: #c7d2fe;

  --success: #10b981;
  --success-bg: #ecfdf5;
  --success-text: #047857;
  --warning: #f59e0b;
  --warning-bg: #fffbeb;
  --warning-text: #b45309;
  --danger: #ef4444;
  --danger-bg: #fef2f2;
  --danger-text: #b91c1c;

  --radius: 20px;
  --radius-sm: 13px;
  --card-shadow: 0 10px 25px -5px rgba(15, 23, 42, 0.06), 0 4px 0px #e2e8f0;
  --btn-shadow: 0 4px 0px #3730a3;
  --hero-bg: linear-gradient(135deg, #eef2ff 0%, #ffffff 65%, #ecfdf5 100%);
  --icon-stroke: 2.15;
  --icon-box-bg: #eef2ff;
  --icon-box-color: #4f46e5;
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg);
  background-image: var(--bg-pattern);
  background-size: var(--bg-pattern-size);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.58;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, .brand-title, .topic-title, .section-title {
  font-family: var(--font-display);
  letter-spacing: -0.02em;
}

code {
  font-family: var(--font-mono);
  background: var(--code-bg);
  color: var(--code-text);
  border: 1px solid var(--code-border);
  padding: 0.14em 0.45em;
  border-radius: 6px;
  font-size: 0.91em;
  font-weight: 600;
}

/* SVG IKONY */
.svg-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.svg-icon svg {
  width: 100%;
  height: 100%;
  stroke-width: var(--icon-stroke);
}

.icon-xs { width: 15px; height: 15px; }
.icon-sm { width: 18px; height: 18px; }
.icon-md { width: 22px; height: 22px; }
.icon-lg { width: 26px; height: 26px; }

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

.subj-icon-wrap {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background: var(--icon-box-bg);
  color: var(--icon-box-color);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 6px;
  border: 1px solid var(--border);
  transition: all 0.15s ease;
}

.app-shell {
  max-width: 1120px;
  margin: 0 auto;
  padding: 16px;
}

/* TOPBAR */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 18px;
  background: var(--bg-card);
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--card-shadow);
  margin-bottom: 14px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
}

.brand-logo {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: var(--primary);
  color: var(--primary-contrast);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 9px;
  box-shadow: var(--btn-shadow);
}

.brand-title {
  font-weight: 800;
  font-size: 1.2rem;
}

.brand-subtitle {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.topbar-stats {
  display: flex;
  align-items: center;
  gap: 8px;
}

.stat-pill {
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--bg-elevated);
  border: var(--border-width) solid var(--border);
  padding: 6px 12px;
  border-radius: 999px;
  font-size: 0.86rem;
  font-weight: 600;
}

.due-pill {
  border-color: var(--border-strong);
  background: var(--code-bg);
  color: var(--code-text);
}

/* SUBJECT BAR */
.subject-bar {
  display: flex;
  gap: 10px;
  overflow-x: auto;
  padding-bottom: 6px;
  margin-bottom: 18px;
  scrollbar-width: none;
}
.subject-bar::-webkit-scrollbar {
  display: none;
}

.subject-tab {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 14px;
  border-radius: var(--radius);
  background: var(--bg-card);
  border: var(--border-width) solid var(--border);
  color: var(--text-muted);
  cursor: pointer;
  white-space: nowrap;
  font-weight: 600;
  font-size: 0.92rem;
  box-shadow: var(--card-shadow);
  transition: all 0.16s ease;
}

.subject-tab:hover {
  border-color: var(--primary);
  color: var(--text);
}

.subject-tab.active {
  border-color: var(--primary);
  color: var(--text);
  background: var(--bg-elevated);
}

.subject-tab.active .subj-icon-wrap {
  background: var(--primary);
  color: var(--primary-contrast);
}

.subject-badge {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  padding: 2px 8px;
  border-radius: 999px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  color: var(--text);
}

/* HERO BANNER & TLAČÍTKA */
.hero-banner {
  background: var(--hero-bg);
  border: var(--border-width) solid var(--border-strong);
  border-radius: var(--radius);
  box-shadow: var(--card-shadow);
  padding: 22px;
  margin-bottom: 22px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.hero-info h1 {
  font-size: 1.45rem;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.hero-info p {
  color: var(--text-muted);
  font-size: 0.94rem;
  max-width: 640px;
}

.hero-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

button {
  font-family: var(--font-sans);
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: var(--primary);
  color: var(--primary-contrast);
  border: var(--border-width) solid var(--border);
  font-weight: 700;
  padding: 11px 18px;
  border-radius: var(--radius-sm);
  font-size: 0.93rem;
  box-shadow: var(--btn-shadow);
  transition: all 0.14s ease;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.btn-primary:hover {
  background: var(--primary-hover);
  transform: translateY(-1px);
}
.btn-primary:active {
  transform: translateY(2px);
  box-shadow: 0 1px 0px #3730a3;
}

.btn-secondary {
  background: var(--bg-elevated);
  color: var(--text);
  border: var(--border-width) solid var(--border);
  font-weight: 600;
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.91rem;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: all 0.14s ease;
}
.btn-secondary:hover {
  border-color: var(--primary);
}

.btn-ghost {
  background: transparent;
  color: var(--text-muted);
  border: var(--border-width) solid var(--border);
  padding: 7px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.84rem;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.btn-ghost:hover {
  color: var(--text);
  border-color: var(--primary);
}

.btn-warning {
  background: var(--warning);
  color: #111111;
  border: var(--border-width) solid var(--border);
  font-weight: 700;
  padding: 9px 15px;
  border-radius: var(--radius-sm);
  display: inline-flex;
  align-items: center;
  gap: 7px;
}

/* TOPICS GRID */
.topics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 16px;
}

.topic-card {
  background: var(--bg-card);
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--card-shadow);
  padding: 18px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 14px;
  transition: transform 0.15s ease, border-color 0.15s ease;
}

.topic-card:hover {
  transform: translateY(-2px);
}

.topic-card.unlocked {
  border-left: 5px solid var(--success);
}

.topic-card.ready_ahead {
  border-left: 5px solid var(--warning);
}

.topic-card.locked {
  opacity: 0.62;
}

.topic-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 8px;
}

.topic-num {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: var(--text-muted);
}

.status-tag {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 0.73rem;
  font-weight: 700;
  padding: 3px 9px;
  border-radius: 999px;
  font-family: var(--font-mono);
}
.status-tag.unlocked {
  background: var(--success-bg);
  color: var(--success-text);
}
.status-tag.ready_ahead {
  background: var(--warning-bg);
  color: var(--warning-text);
}
.status-tag.locked {
  background: var(--bg-elevated);
  color: var(--text-muted);
}

.topic-title {
  font-size: 1.12rem;
  font-weight: 700;
  margin: 6px 0 4px;
}

.topic-subtitle {
  font-size: 0.86rem;
  color: var(--text-muted);
}

.topic-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  font-size: 0.78rem;
  color: var(--text-muted);
}

.meta-chip {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  padding: 4px 9px;
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.topic-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding-top: 10px;
  border-top: 1px solid var(--border);
}

/* PRACTICE SESSION CARD */
.practice-container {
  max-width: 780px;
  margin: 0 auto;
}

.practice-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
  gap: 10px;
}

.progress-bar-wrap {
  flex: 1;
  height: 9px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 999px;
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background: var(--primary);
  transition: width 0.25s ease;
}

.question-card {
  background: var(--bg-card);
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  padding: 26px;
  box-shadow: var(--card-shadow);
}

.q-badges {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 14px;
}

.q-type-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  font-weight: 700;
  padding: 5px 11px;
  border-radius: 999px;
  background: var(--code-bg);
  color: var(--code-text);
  border: 1px solid var(--code-border);
}

.q-type-badge.calc {
  background: var(--success-bg);
  color: var(--success-text);
}

.q-title {
  font-family: var(--font-display);
  font-size: 0.95rem;
  color: var(--text-muted);
  font-weight: 600;
  margin-bottom: 8px;
}

.q-text {
  font-size: 1.16rem;
  line-height: 1.65;
  margin-bottom: 22px;
}

/* NUMERIC / TEXT INPUT FORM */
.answer-form {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: stretch;
  margin-bottom: 16px;
}

.input-group {
  flex: 1;
  min-width: 220px;
  display: flex;
  align-items: center;
  background: var(--bg-elevated);
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 4px 14px;
  transition: border-color 0.15s;
}
.input-group:focus-within {
  border-color: var(--primary);
}

.answer-input {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 600;
  padding: 10px 4px;
  outline: none;
  width: 100%;
}

.unit-label {
  font-family: var(--font-mono);
  color: var(--text-muted);
  font-weight: 700;
  font-size: 0.95rem;
  padding-left: 8px;
  white-space: nowrap;
}

/* MULTIPLE CHOICE OPTIONS */
.mc-options {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 18px;
}

.mc-option {
  text-align: left;
  background: var(--bg-elevated);
  border: var(--border-width) solid var(--border);
  color: var(--text);
  padding: 14px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.97rem;
  line-height: 1.48;
  transition: all 0.14s;
}
.mc-option:hover:not(:disabled) {
  border-color: var(--primary);
}
.mc-option.correct {
  border-color: var(--success);
  background: var(--success-bg);
  color: var(--success-text);
  font-weight: 600;
}
.mc-option.wrong {
  border-color: var(--danger);
  background: var(--danger-bg);
  color: var(--danger-text);
}

/* SOLUTION BOX */
.solution-box {
  margin-top: 20px;
  padding: 18px;
  border-radius: var(--radius-sm);
  background: var(--bg-elevated);
  border: var(--border-width) solid var(--border);
  animation: fadeIn 0.2s ease;
}

.solution-box.correct {
  border-color: var(--success);
}
.solution-box.wrong {
  border-color: var(--danger);
}

.result-banner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  font-weight: 700;
  font-size: 1.04rem;
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}
.result-banner.correct {
  color: var(--success-text);
}
.result-banner.wrong {
  color: var(--danger-text);
}

.formula-pill {
  display: inline-block;
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  color: var(--code-text);
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.92rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.steps-list {
  padding-left: 20px;
  margin-bottom: 16px;
}
.steps-list li {
  margin-bottom: 7px;
  font-size: 0.95rem;
}

.srs-Controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--border);
}

.srs-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 640px) {
  .hide-mobile {
    display: none;
  }
  .question-card {
    padding: 18px;
  }
  .q-text {
    font-size: 1.05rem;
  }
  .hero-banner {
    padding: 16px;
  }
}