:root {
  /* Палитра */
  --color-bg: #fff;
  --color-fg: #0b0b0b;
  --color-muted: #666;
  --color-primary: #0a84ff;
  --color-danger: #b00020;
  /* Типографика и 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 и тени */
  --radius: 12px;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.08), 0 8px 24px rgba(0, 0, 0, 0.08);
}

body.theme-dark {
  --color-bg: #0b0b0b;
  --color-fg: #f5f5f5;
  --color-muted: #aaa;
  --color-primary: #6aa2ff;
}

* {
  box-sizing: border-box;
}

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

html {
  scroll-behavior: smooth;
}

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

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

.site-header {
  background:
    linear-gradient(to top, rgba(0, 0, 0, 0.55), rgba(0, 0, 0, 0.15)),
    url("assets/hero.jpg") center/cover no-repeat;
  color: #fff;
  padding: clamp(2rem, 6vw, 6rem) 1rem; /* адаптивные
отступы */
  border-radius: var(--radius);
}

.site-header__brand {
  font-size: var(--space-5);
}

.site-nav__item {
  font-size: var(--space-4);
}

.site-nav__link--about,
.site-nav__link--main,
.site-nav__link--contacts {
  text-decoration: none;
  color: var(--color-bg);
}

.site-nav__link--about:hover,
.site-nav__link--main:hover,
.site-nav__link--contacts:hover {
  background-color: var(--color-primary);
  border-radius: var(--radius);
}

.container {
  width: min(100% - 2 * var(--space-4), 1120px);
  margin-inline: auto;
}

.section {
  padding-block: var(--space-5);
}

.section__title {
  margin: 0 0 var(--space-3);
}

.site-nav:hover {
  border-width: 3px;
  outline: 2px dashed var(--color-primary);
  outline-offset: 4px;
}

.site-main:target {
  outline: 2px dashed var(--color-primary);
  outline-offset: 4px;
}

label {
  display: block;
  margin: 0.5rem 0 0.25rem;
}

input,
select,
textarea,
button {
  width: 100%;
  max-width: 480px;
  padding: 0.2rem;
  border: 2px solid #c8c8c8;
  border-radius: 8px;
  background: #fff;
}

button,
[type="submit"] {
  background: #0a84ff;
  color: #fff;
  border: none;
  cursor: pointer;
}

:where(input, select, textarea, button):focus-visible {
  outline: 2px solid #0a84ff;
  outline-offset: 2px;
}

button:hover {
  filter: brightness(0.95);
}

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