/* Токены */
:root {
  /* Палитра */
  --color-bg: #fff;
  --color-fg: #0b0b0b;
  --color-muted: #666;
  --color-primary: #0a84ff;
  --color-danger: #b00020;
  --color-success: #2e7d32;

  /* Типографика + размеры */
  --font-body: system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 16px;
  --space-4: 24px;
  --space-5: 40px;

  /* Скругления + тени */
  --radius: 12px;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.08), 0 8px 24px rgba(0, 0, 0, 0.08);
}

:root.theme-dark {
  /* Палитра для тёмной темы */
  --color-bg: #121212;
  --color-fg: #fff;
  --color-muted: #999;
  --color-primary: #3a9dff;
  --color-danger: #ff5252;
  --color-success: #4caf50;
}

/* Сброс */
* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  background: var(--color-bg);
  color: var(--color-fg);
  font-family: var(--font-body);
  line-height: 1.5;
  padding: var(--space-3);
}

/* HEADER */
.site-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--color-muted);
  margin-bottom: var(--space-5);
  position: relative;
}

.site-header__brand {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--color-primary);
  text-decoration: none;
}

.site-header__controls {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* Переключатель темы */
.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
  border-radius: 50%;
  transition: background-color 0.2s ease;
  margin-left: var(--space-3);
  color: var(--color-fg);
}

.theme-toggle:hover {
  background-color: rgba(0, 0, 0, 0.1);
}

.theme-dark .theme-toggle:hover {
  background-color: rgba(255, 255, 255, 0.1);
}

.theme-toggle svg {
  width: 24px;
  height: 24px;
  fill: currentColor;
}

.theme-toggle__icon--sun,
.theme-toggle__icon--moon {
  display: none;
}

.theme-dark .theme-toggle__icon--sun {
  display: block;
}

:root:not(.theme-dark) .theme-toggle__icon--moon {
  display: block;
}

/* NAVIGATION */
.site-nav__list {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: var(--space-4);
}

.site-nav__item {
  margin: 0;
}

.site-nav__link {
  color: var(--color-fg);
  text-decoration: none;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius);
  transition: all 0.2s ease;
}

.site-nav__link:hover {
  background-color: var(--color-primary);
  color: white;
}

.site-nav__link:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.site-nav__link--active {
  background-color: var(--color-primary);
  color: white;
}

/* BREADCRUMBS */
.breadcrumbs {
  margin-bottom: var(--space-4);
  padding: var(--space-2) 0;
}

.breadcrumbs__list {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: var(--space-2);
}

.breadcrumbs__item:not(:last-child)::after {
  content: "→";
  margin-left: var(--space-2);
  color: var(--color-muted);
}

.breadcrumbs__link {
  color: var(--color-primary);
  text-decoration: none;
}

.breadcrumbs__link:hover {
  text-decoration: underline;
}

.breadcrumbs__current {
  color: var(--color-muted);
}

/* FORM */
.form {
  max-width: 600px;
  margin: 0 auto;
}

.form-group {
  margin-bottom: var(--space-4);
}

.form__label {
  display: block;
  margin: 0 0 var(--space-2);
  font-weight: 500;
}

.form__input,
.form__select,
.form__textarea {
  width: 100%;
  padding: var(--space-3);
  border: 1px solid var(--color-muted);
  border-radius: var(--radius);
  font-family: inherit;
  font-size: 1rem;
  background: var(--color-bg);
  color: var(--color-fg);
}

.form__input:focus,
.form__select:focus,
.form__textarea:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.form__textarea {
  min-height: 120px;
  resize: vertical;
}

.form__help {
  display: block;
  margin-top: var(--space-1);
  color: var(--color-muted);
  font-size: 0.875rem;
}

/* BTNS */
.btn {
  padding: var(--space-3) var(--space-4);
  border: none;
  border-radius: var(--radius);
  font-family: inherit;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn--primary {
  background: var(--color-primary);
  color: white;
}

.btn--primary:hover {
  filter: brightness(0.95);
}

.btn--secondary {
  background: var(--color-muted);
  color: white;
}

/* MODAL */
.modal {
  padding: var(--space-4);
  border: none;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  width: min(90vw, 600px);
  background: var(--color-bg);
  color: var(--color-fg);
}

.modal::backdrop {
  background: rgba(0, 0, 0, 0.5);
}

.modal__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-4);
}

.modal__title {
  margin: 0;
}

.modal__close {
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--color-fg);
}

/* HEROSECTION */
.hero {
  background: linear-gradient(to top, rgba(0, 0, 0, 0.55), rgba(0, 0, 0, 0.15)),
    url("https://images.unsplash.com/photo-1501504905252-473c47e087f8?ixlib=rb-4.0.3&auto=format&fit=crop&w=1920&q=80") center/cover no-repeat;
  color: white;
  padding: clamp(2rem, 6vw, 6rem) 1rem;
  border-radius: var(--radius);
  margin-bottom: var(--space-5);
  text-align: center;
}

.hero__title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  margin: 0 0 var(--space-3);
}

.hero__subtitle {
  font-size: clamp(1rem, 3vw, 1.5rem);
  margin: 0;
}

/* RESPONSIVEIMAGE */
.responsive-image {
  width: 100%;
  height: auto;
  border-radius: var(--radius);
  margin: var(--space-4) 0;
}

/* video */
.video-container {
  aspect-ratio: 16/9;
  width: min(100%, 960px);
  margin: var(--space-4) auto;
}

.video-container iframe {
  width: 100%;
  height: 100%;
  border: 0;
  border-radius: var(--radius);
}

/* UTILITY CLASSES */
.text-center {
  text-align: center;
}

.mb-1 { margin-bottom: var(--space-1); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-3 { margin-bottom: var(--space-3); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-5 { margin-bottom: var(--space-5); }

.mt-1 { margin-top: var(--space-1); }
.mt-2 { margin-top: var(--space-2); }
.mt-3 { margin-top: var(--space-3); }
.mt-4 { margin-top: var(--space-4); }
.mt-5 { margin-top: var(--space-5); }

/* ===== STATES ===== */
:where(a, button, input, select, textarea):focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

:disabled,
[aria-disabled="true"] {
  opacity: 0.6;
  cursor: not-allowed;
}

[aria-invalid="true"] {
  border-color: var(--color-danger);
  background-color: #fff8f8;
}

.theme-dark [aria-invalid="true"] {
  background-color: #2a1a1a;
}

html {
  scroll-behavior: smooth;
}

:target {
  outline: 2px dashed var(--color-primary);
  outline-offset: 4px;
  padding: var(--space-2);
  border-radius: var(--radius);
}

/* ACTIONS */
.form-actions {
  display: flex;
  gap: var(--space-3);
  margin-top: var(--space-4);
  justify-content: flex-end;
}