/* =====================================================
   MTS-style Mobile Menu (technorazum.ru)
   Mobile-only @media (max-width: 768px)
   - CSS-only toggle via checkbox hack
   - Minimal JS enhances a11y (ESC, focus trap, aria-expanded)
   ===================================================== */

/* === Design tokens === */
:root {
  --mm-color-bg: #ffffff;
  --mm-color-text: #111111;
  --mm-color-muted: #6b7280;
  --mm-color-border: #e5e7eb;
  --mm-color-hover: #f3f4f6;
  --mm-color-accent: #ff0032;        /* MTS red */
  --mm-color-backdrop: rgba(0, 0, 0, 0.5);
  --mm-shadow: -8px 0 24px rgba(0, 0, 0, 0.12);
  --mm-radius: 8px;
  --mm-tap: 44px;                    /* WCAG / Apple HIG min tap target */
  --mm-z-backdrop: 999;
  --mm-z-drawer: 1000;
  --mm-z-burger: 1001;
  --mm-drawer-w: 85vw;               /* drawer = 85% viewport */
  --mm-drawer-max: 400px;
  --mm-duration: 0.28s;
  --mm-ease: cubic-bezier(0.32, 0.72, 0, 1);
  --mm-font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

/* === Visually-hidden checkboxes (checkbox hack) === */
.mm-burger-toggle,
.mm-group-toggle {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* === Default (desktop): burger + drawer hidden === */
.mm-burger-btn,
.mm-drawer,
.mm-drawer-backdrop {
  display: none;
}

/* =================================================
   MOBILE  (≤ 768px)
   ================================================= */
@media (max-width: 768px) {

  /* Header */
  .site-header {
    position: sticky;
    top: 0;
    z-index: var(--mm-z-burger);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
    min-height: 56px;
    padding: 0 8px 0 16px;
    background: var(--mm-color-bg);
    border-bottom: 1px solid var(--mm-color-border);
    font-family: var(--mm-font);
    -webkit-tap-highlight-color: transparent;
  }
  .site-header .logo {
    display: inline-flex;
    align-items: center;
    text-decoration: none;
    color: var(--mm-color-text);
    font-weight: 700;
    font-size: 18px;
  }
  .site-header .desktop-nav { display: none; }

  /* Burger button */
  .mm-burger-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: var(--mm-tap);
    height: var(--mm-tap);
    margin-left: auto;
    background: transparent;
    border: 0;
    border-radius: var(--mm-radius);
    color: var(--mm-color-text);
    cursor: pointer;
    transition: background-color 0.18s var(--mm-ease),
                opacity var(--mm-duration) var(--mm-ease);
  }
  .mm-burger-btn:hover  { background: var(--mm-color-hover); }
  .mm-burger-btn:focus-visible {
    outline: 0;
    box-shadow: 0 0 0 2px var(--mm-color-accent);
  }
  .mm-burger-btn svg { width: 24px; height: 24px; display: block; }

  /* Backdrop */
  .mm-drawer-backdrop {
    display: block;
    position: fixed;
    inset: 0;
    background: transparent;
    pointer-events: none;
    cursor: pointer;
    z-index: var(--mm-z-backdrop);
    transition: background-color var(--mm-duration) var(--mm-ease);
  }

  /* Drawer */
  .mm-drawer {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: var(--mm-drawer-w);
    max-width: var(--mm-drawer-max);
    background: var(--mm-color-bg);
    color: var(--mm-color-text);
    z-index: var(--mm-z-drawer);
    box-shadow: var(--mm-shadow);
    transform: translateX(100%);
    visibility: hidden;
    transition: transform var(--mm-duration) var(--mm-ease),
                visibility 0s linear var(--mm-duration);
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    overscroll-behavior: contain;
    font-family: var(--mm-font);
  }

  /* === Open state (CSS-only) === */
  .mm-burger-toggle:checked ~ .mm-drawer {
    transform: translateX(0);
    visibility: visible;
    transition: transform var(--mm-duration) var(--mm-ease),
                visibility 0s linear 0s;
  }
  .mm-burger-toggle:checked ~ .mm-drawer-backdrop {
    background: var(--mm-color-backdrop);
    pointer-events: auto;
  }
  .mm-burger-toggle:checked ~ .mm-burger-btn {
    opacity: 0;
    pointer-events: none;
  }

  /* Drawer header (sticky inside drawer) */
  .mm-drawer-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-shrink: 0;
    min-height: 56px;
    padding: 0 8px 0 20px;
    background: var(--mm-color-bg);
    border-bottom: 1px solid var(--mm-color-border);
    position: sticky;
    top: 0;
    z-index: 1;
  }
  .mm-drawer-title {
    font-size: 18px;
    font-weight: 600;
    letter-spacing: -0.01em;
  }
  .mm-drawer-close {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: var(--mm-tap);
    height: var(--mm-tap);
    cursor: pointer;
    color: var(--mm-color-text);
    border-radius: var(--mm-radius);
    transition: background-color 0.18s var(--mm-ease);
  }
  .mm-drawer-close:hover  { background: var(--mm-color-hover); }
  .mm-drawer-close:focus-visible {
    outline: 0;
    box-shadow: 0 0 0 2px var(--mm-color-accent);
  }
  .mm-drawer-close svg { width: 24px; height: 24px; display: block; }

  /* Nav + groups */
  .mm-drawer-nav {
    flex: 1 1 auto;
    padding: 4px 0 24px;
  }
  .mm-menu-group {
    border-bottom: 1px solid var(--mm-color-border);
  }
  .mm-menu-group:last-child { border-bottom: 0; }

  .mm-group-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    width: 100%;
    min-height: var(--mm-tap);
    padding: 0 20px;
    cursor: pointer;
    font-size: 16px;
    font-weight: 500;
    color: var(--mm-color-text);
    user-select: none;
    -webkit-tap-highlight-color: transparent;
    transition: background-color 0.15s var(--mm-ease);
  }
  .mm-group-header:hover  { background: var(--mm-color-hover); }
  .mm-group-header:focus-visible {
    outline: 0;
    box-shadow: inset 0 0 0 2px var(--mm-color-accent);
  }
  .mm-group-arrow {
    width: 20px;
    height: 20px;
    color: var(--mm-color-muted);
    flex-shrink: 0;
    transition: transform var(--mm-duration) var(--mm-ease);
  }
  .mm-group-toggle:checked + .mm-group-header .mm-group-arrow {
    transform: rotate(180deg);
  }

  /* Group list (accordion body) */
  .mm-group-list {
    max-height: 0;
    overflow: hidden;
    list-style: none;
    margin: 0;
    padding: 0;
    transition: max-height var(--mm-duration) var(--mm-ease);
  }
  .mm-group-toggle:checked ~ .mm-group-list { max-height: 600px; }

  .mm-group-list a {
    display: flex;
    align-items: center;
    min-height: var(--mm-tap);
    padding: 0 20px 0 36px;
    color: var(--mm-color-text);
    text-decoration: none;
    font-size: 15px;
    font-weight: 400;
    -webkit-tap-highlight-color: transparent;
    transition: background-color 0.15s var(--mm-ease);
  }
  .mm-group-list a:hover  { background: var(--mm-color-hover); }
  .mm-group-list a:focus-visible {
    outline: 0;
    background: var(--mm-color-hover);
    box-shadow: inset 0 0 0 2px var(--mm-color-accent);
  }
}

/* === Reduced motion === */
@media (prefers-reduced-motion: reduce) {
  .mm-drawer,
  .mm-drawer-backdrop,
  .mm-burger-btn,
  .mm-group-arrow,
  .mm-group-list {
    transition-duration: 0.01ms !important;
  }
}