/* ============================================
   MATURITNÝ ŤAHÁK – STYLE SYSTEM
   Dark Mode, Premium Design
   ============================================ */

/* === Google Fonts === */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600&display=swap');

/* === CSS Variables === */
:root {
  --bg-primary: #0f0f1a;
  --bg-secondary: #161625;
  --bg-card: #1c1c30;
  --bg-card-hover: #22223a;
  --bg-code: #12121f;
  --bg-code-header: #1a1a2e;

  --text-primary: #e8e8f0;
  --text-secondary: #a0a0b8;
  --text-muted: #6a6a82;
  --text-code: #c5c8c6;

  --accent-primary: #7c5cfc;
  --accent-primary-glow: rgba(124, 92, 252, 0.25);
  --accent-secondary: #5eead4;
  --accent-warning: #f7b955;
  --accent-danger: #f87171;
  --accent-info: #60a5fa;
  --accent-success: #4ade80;

  --border-color: rgba(255, 255, 255, 0.06);
  --border-active: rgba(124, 92, 252, 0.4);

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-xl: 18px;

  --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 30px rgba(124, 92, 252, 0.15);

  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
  --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);

  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
}

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

html {
  font-size: 15px;
}

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Subtle gradient background */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background:
    radial-gradient(ellipse at 20% 0%, rgba(124, 92, 252, 0.08) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 100%, rgba(94, 234, 212, 0.05) 0%, transparent 50%);
  pointer-events: none;
  z-index: 0;
}

/* === Header === */
.header {
  position: relative;
  z-index: 10;
  text-align: center;
  padding: 2.5rem 1.5rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  background: linear-gradient(180deg, rgba(124, 92, 252, 0.06) 0%, transparent 100%);
}

.header__icon {
  font-size: 2.8rem;
  margin-bottom: 0.5rem;
  display: block;
  animation: float 3s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0px); }
  50% { transform: translateY(-6px); }
}

.header__title {
  font-size: 1.9rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent-primary) 0%, var(--accent-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.5px;
}

.header__subtitle {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 0.3rem;
  font-weight: 500;
}

/* === Tab Navigation === */
.tabs {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(15, 15, 26, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  padding: 0.6rem 1rem;
}

.tabs__list {
  display: flex;
  gap: 0.4rem;
  list-style: none;
  max-width: 900px;
  margin: 0 auto;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
}

.tabs__list::-webkit-scrollbar {
  display: none;
}

.tabs__btn {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.55rem 1rem;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  background: transparent;
  color: var(--text-secondary);
  font-family: var(--font-sans);
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: all var(--transition-normal);
  position: relative;
}

.tabs__btn:hover {
  background: rgba(124, 92, 252, 0.08);
  color: var(--text-primary);
  border-color: var(--border-color);
}

.tabs__btn.active {
  background: rgba(124, 92, 252, 0.12);
  color: #fff;
  border-color: var(--border-active);
  box-shadow: var(--shadow-glow);
}

.tabs__btn.active::after {
  content: '';
  position: absolute;
  bottom: -0.65rem;
  left: 50%;
  transform: translateX(-50%);
  width: 24px;
  height: 2px;
  background: var(--accent-primary);
  border-radius: 2px;
}

.tabs__icon {
  font-size: 1rem;
}

/* === Main Content === */
.main {
  position: relative;
  z-index: 1;
  max-width: 900px;
  margin: 0 auto;
  padding: 1.5rem 1rem 4rem;
}

/* === Tab Content === */
.tab-content {
  display: none;
  animation: fadeSlideIn 0.35s ease;
}

.tab-content.active {
  display: block;
}

@keyframes fadeSlideIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* === Sub-Navigation (within tabs) === */
.subnav {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.8rem 0;
  margin-bottom: 1rem;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
  position: sticky;
  top: 52px;
  z-index: 50;
  background: linear-gradient(180deg, rgba(15, 15, 26, 0.95) 0%, rgba(15, 15, 26, 0.88) 100%);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  margin-left: -1rem;
  margin-right: -1rem;
  padding-left: 1rem;
  padding-right: 1rem;
}

.subnav::-webkit-scrollbar {
  display: none;
}

.subnav__link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.5rem 1rem;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-decoration: none;
  white-space: nowrap;
  transition: all var(--transition-normal);
  border: 1px solid var(--border-color);
  background: rgba(255, 255, 255, 0.02);
  cursor: pointer;
  position: relative;
}

.subnav__link:hover {
  color: var(--text-primary);
  background: rgba(124, 92, 252, 0.1);
  border-color: rgba(124, 92, 252, 0.25);
  transform: translateY(-1px);
}

.subnav__link.active {
  color: #fff;
  background: linear-gradient(135deg, rgba(124, 92, 252, 0.2) 0%, rgba(94, 234, 212, 0.1) 100%);
  border-color: rgba(124, 92, 252, 0.4);
  box-shadow: 0 2px 12px rgba(124, 92, 252, 0.2), inset 0 1px 0 rgba(255, 255, 255, 0.05);
}

.subnav__num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  font-size: 0.65rem;
  font-weight: 700;
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-muted);
  transition: all var(--transition-normal);
  flex-shrink: 0;
}

.subnav__link:hover .subnav__num {
  background: rgba(124, 92, 252, 0.2);
  color: var(--accent-primary);
}

.subnav__link.active .subnav__num {
  background: linear-gradient(135deg, var(--accent-primary), #9b7cfc);
  color: #fff;
  box-shadow: 0 0 8px rgba(124, 92, 252, 0.4);
}

.subnav__empty {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-style: italic;
  padding: 0.5rem 0;
}

/* === Section Cards === */
.section {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin-bottom: 1rem;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-card);
}

.section:hover {
  border-color: rgba(124, 92, 252, 0.15);
  box-shadow: var(--shadow-card), var(--shadow-glow);
}

.section__number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  background: linear-gradient(135deg, var(--accent-primary), #9b7cfc);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: var(--radius-sm);
  margin-right: 0.6rem;
  flex-shrink: 0;
}

.section__title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  margin-bottom: 0.6rem;
}

.section__desc {
  color: var(--text-secondary);
  font-size: 0.88rem;
  line-height: 1.65;
  margin-bottom: 1rem;
}

/* === Subsections === */
.subsection {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border-color);
}

.subsection__title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--accent-secondary);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.subsection__title::before {
  content: '▸';
  color: var(--accent-primary);
  font-size: 0.8rem;
}

.subsection__desc {
  color: var(--text-secondary);
  font-size: 0.85rem;
  line-height: 1.6;
  margin-bottom: 0.7rem;
}

/* === Code Blocks === */
.code-block {
  position: relative;
  margin: 0.7rem 0;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border-color);
}

.code-block__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.4rem 0.8rem;
  background: var(--bg-code-header);
  border-bottom: 1px solid var(--border-color);
  font-size: 0.72rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.code-block__lang {
  display: flex;
  align-items: center;
  gap: 0.3rem;
}

.code-block__lang::before {
  content: '';
  width: 7px;
  height: 7px;
  background: var(--accent-success);
  border-radius: 50%;
}

.code-block__copy {
  background: none;
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  font-size: 0.7rem;
  font-family: var(--font-sans);
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.code-block__copy:hover {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
  border-color: var(--accent-primary);
}

.code-block__copy.copied {
  color: var(--accent-success);
  border-color: var(--accent-success);
}

.code-block pre {
  margin: 0;
  padding: 1rem;
  background: var(--bg-code);
  overflow-x: auto;
  scrollbar-width: thin;
  scrollbar-color: rgba(255, 255, 255, 0.1) transparent;
}

.code-block pre::-webkit-scrollbar {
  height: 4px;
}

.code-block pre::-webkit-scrollbar-track {
  background: transparent;
}

.code-block pre::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 4px;
}

.code-block code {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  line-height: 1.65;
  color: var(--text-code);
  white-space: pre;
}

/* === Syntax Highlighting (Inline) === */
.code-block .kw { color: #c792ea; }          /* keywords: import, def, if, for */
.code-block .fn { color: #82aaff; }          /* function calls */
.code-block .st { color: #c3e88d; }          /* strings */
.code-block .cm { color: #546e7a; font-style: italic; }  /* comments */
.code-block .nb { color: #f78c6c; }          /* numbers */
.code-block .op { color: #89ddff; }          /* operators */
.code-block .var { color: #eeffff; }         /* variables */
.code-block .cls { color: #ffcb6b; }         /* class/module names */
.code-block .dec { color: #c792ea; }         /* decorators */
.code-block .param { color: #f07178; }       /* parameters */
.code-block .bi { color: #82aaff; }          /* builtins like print, int, range */

/* === Warning / Tip Boxes === */
.alert {
  display: flex;
  gap: 0.7rem;
  padding: 0.85rem 1rem;
  border-radius: var(--radius-md);
  margin: 0.8rem 0;
  font-size: 0.84rem;
  line-height: 1.55;
  border: 1px solid;
}

.alert__icon {
  font-size: 1.1rem;
  flex-shrink: 0;
  margin-top: 0.1rem;
}

.alert--warning {
  background: rgba(247, 185, 85, 0.08);
  border-color: rgba(247, 185, 85, 0.2);
  color: var(--accent-warning);
}

.alert--tip {
  background: rgba(94, 234, 212, 0.06);
  border-color: rgba(94, 234, 212, 0.15);
  color: var(--accent-secondary);
}

.alert--info {
  background: rgba(96, 165, 250, 0.06);
  border-color: rgba(96, 165, 250, 0.15);
  color: var(--accent-info);
}

.alert--danger {
  background: rgba(248, 113, 113, 0.06);
  border-color: rgba(248, 113, 113, 0.15);
  color: var(--accent-danger);
}

/* Inline code */
.inline-code {
  font-family: var(--font-mono);
  font-size: 0.82em;
  background: rgba(124, 92, 252, 0.1);
  color: var(--accent-primary);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  border: 1px solid rgba(124, 92, 252, 0.15);
}

/* === Placeholder (empty tabs) === */
.placeholder {
  text-align: center;
  padding: 4rem 2rem;
  color: var(--text-muted);
}

.placeholder__icon {
  font-size: 3rem;
  margin-bottom: 1rem;
  opacity: 0.5;
  display: block;
}

.placeholder__title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 0.4rem;
}

.placeholder__desc {
  font-size: 0.85rem;
  max-width: 340px;
  margin: 0 auto;
  line-height: 1.6;
}

/* === Footer === */
.footer {
  position: relative;
  z-index: 1;
  text-align: center;
  padding: 1.5rem;
  color: var(--text-muted);
  font-size: 0.75rem;
  border-top: 1px solid var(--border-color);
}

/* === Scrollbar === */
::-webkit-scrollbar {
  width: 6px;
}

::-webkit-scrollbar-track {
  background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
  background: rgba(124, 92, 252, 0.3);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: rgba(124, 92, 252, 0.5);
}

/* === Selection === */
::selection {
  background: rgba(124, 92, 252, 0.3);
  color: #fff;
}

/* === Responsive (base) === */
@media (max-width: 640px) {
  html {
    font-size: 14px;
  }

  .header {
    padding: 1.5rem 1rem 1rem;
  }

  .header__title {
    font-size: 1.5rem;
  }

  .tabs {
    padding: 0.4rem 0.6rem;
  }

  .tabs__btn {
    padding: 0.45rem 0.75rem;
    font-size: 0.78rem;
  }

  .section {
    padding: 1.1rem;
  }

  .main {
    padding: 1rem 0.6rem 3rem;
  }
}

/* ============================================================
   SIDEBAR + LAYOUT
   ============================================================ */

/* Section colour tokens */
#tk-kostra    { --section-color: #60a5fa; }
#tk-kreslenie { --section-color: #2dd4bf; }
#tk-vstupy    { --section-color: #f97316; }
#tk-eventy    { --section-color: #eab308; }
#tk-vzorec    { --section-color: #a78bfa; }
#tk-animacie  { --section-color: #f472b6; }
#tk-objekty   { --section-color: #34d399; }
#tk-subory    { --section-color: #fb923c; }

/* Colour-coded left border + badge */
.section {
  border-left: 3px solid var(--section-color, var(--accent-primary));
}
.section__number {
  background: var(--section-color, var(--accent-primary));
}

/* Per-link colour tokens (same order as sidebar nav) */
.sidebar__nav .sidebar__link:nth-child(1) { --section-color: #60a5fa; }
.sidebar__nav .sidebar__link:nth-child(2) { --section-color: #2dd4bf; }
.sidebar__nav .sidebar__link:nth-child(3) { --section-color: #f97316; }
.sidebar__nav .sidebar__link:nth-child(4) { --section-color: #eab308; }
.sidebar__nav .sidebar__link:nth-child(5) { --section-color: #a78bfa; }
.sidebar__nav .sidebar__link:nth-child(6) { --section-color: #f472b6; }
.sidebar__nav .sidebar__link:nth-child(7) { --section-color: #34d399; }
.sidebar__nav .sidebar__link:nth-child(8) { --section-color: #fb923c; }

/* --- Layout wrapper --- */
.layout {
  display: flex;
  max-width: 1120px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
  align-items: flex-start;
}

.layout > .main {
  flex: 1;
  min-width: 0;
  max-width: none;
  margin: 0;
  padding: 1.5rem 1.5rem 4rem;
}

/* --- Sidebar --- */
.sidebar {
  width: 185px;
  flex-shrink: 0;
  position: sticky;
  top: 52px;
  max-height: calc(100vh - 52px);
  overflow-y: auto;
  scrollbar-width: none;
  border-right: 1px solid var(--border-color);
  background: var(--bg-secondary);
  display: flex;
  flex-direction: column;
  padding: 1rem 0.65rem 1.25rem;
  gap: 0.4rem;
}
.sidebar::-webkit-scrollbar { display: none; }

.sidebar__search {
  width: 100%;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.78rem;
  padding: 0.48rem 0.65rem;
  outline: none;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}
.sidebar__search:focus {
  border-color: rgba(124, 92, 252, 0.5);
  box-shadow: 0 0 0 3px rgba(124, 92, 252, 0.08);
}
.sidebar__search::placeholder { color: var(--text-muted); }

.search-highlight {
  background: rgba(247, 185, 85, 0.25);
  color: #fff;
  border-radius: 3px;
  padding: 0 2px;
  border-bottom: 2px solid var(--accent-warning);
}

.sidebar__group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}
.sidebar__group[hidden] {
  display: none;
}

.sidebar__section-label {
  font-size: 0.6rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0.35rem 0.3rem 0;
}

.sidebar__nav {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
  flex: 1;
}

.sidebar__link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.38rem 0.5rem;
  border-radius: var(--radius-sm);
  font-size: 0.79rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  transition: all var(--transition-fast);
  border: 1px solid transparent;
  white-space: nowrap;
}
.sidebar__link:hover {
  background: rgba(124, 92, 252, 0.07);
  color: var(--text-primary);
  border-color: var(--border-color);
}
.sidebar__link.active {
  background: rgba(124, 92, 252, 0.12);
  color: #fff;
  border-color: var(--border-active);
}

.sidebar__num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 18px;
  height: 18px;
  border-radius: 4px;
  font-size: 0.6rem;
  font-weight: 700;
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-muted);
  flex-shrink: 0;
  transition: all var(--transition-fast);
}
.sidebar__link:hover .sidebar__num,
.sidebar__link.active .sidebar__num {
  background: var(--section-color, var(--accent-primary));
  color: #fff;
}

.sidebar__divider {
  height: 1px;
  background: var(--border-color);
  margin: 0.3rem 0.1rem;
}

.sidebar__bottom {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.sidebar__scroll-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  padding: 0.38rem;
  border-radius: var(--radius-sm);
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  font-size: 0.72rem;
  font-family: var(--font-sans);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  width: 100%;
}
.sidebar__scroll-btn:hover {
  background: rgba(124, 92, 252, 0.07);
  color: var(--text-primary);
  border-color: rgba(124, 92, 252, 0.25);
}

/* --- Search state --- */
.section--hidden { display: none !important; }

/* --- Hide horizontal subnav on desktop (sidebar replaces it) --- */
.subnav { display: none; }

/* --- Responsive: restore subnav on narrow screens --- */
@media (max-width: 860px) {
  .sidebar { display: none; }
  .subnav  { display: flex; }
  .layout > .main { padding: 1rem 0.8rem 3rem; }
}
@media (max-width: 640px) {
  .layout > .main { padding: 1rem 0.6rem 3rem; }
}