/* Cheese — shared left navigation sidebar
   Used by every page (Analysis, Training, Database, Opening Explorer,
   Puzzles) so the nav bar looks and behaves identically everywhere and
   is only downloaded/parsed once. Load this file BEFORE the page's own
   style.css so page-specific rules can still override where needed.
   Does NOT include the 220px content-offset rule — each page handles
   that offset itself (varies: some use .app-container padding, others
   bake it into their own content-container class). */

/* =====================
   LEFT NAVIGATION SIDEBAR
   ===================== */

.left-nav {
    position: fixed;
    left: 0;
    top: 0;
    width: 220px;
    height: 100vh;
    background: rgba(12, 16, 28, 0.72);
    backdrop-filter: blur(28px) saturate(135%);
    -webkit-backdrop-filter: blur(28px) saturate(135%);
    border-right: 1px solid rgba(255, 255, 255, 0.10);
    display: flex;
    flex-direction: column;
    z-index: 100;
    box-shadow: 6px 0 34px rgba(0, 0, 0, 0.45),
                inset 0 1px 0 rgba(255, 255, 255, 0.05),
                inset -1px 0 0 rgba(255, 255, 255, 0.04);
    padding: 0 0 24px 0;
}

/* LOGO */

a.left-nav-logo,
a.left-nav-item {
    text-decoration: none;
    color: inherit;
    display: flex;
}

a.left-nav-logo {
    cursor: pointer;
}

a.left-nav-logo:hover {
    background: rgba(255, 255, 255, 0.04);
}

/* Navigable (non-active, non-disabled) nav item — clickable link.
   Explicit white text so the link never falls back to the inherited body
   colour. The active item is highlighted via its own active rule. */
a.left-nav-item-link {
    cursor: pointer;
    width: 100%;
    color: white;
}

a.left-nav-item-link:hover {
    background: rgba(255, 255, 255, 0.07);
    color: white;
    transform: translateX(3px);
}

.left-nav-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 26px 20px 22px 20px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.07);
    margin-bottom: 16px;
}

.left-nav-logo-icon {
    width: 34px;
    height: 34px;
    flex-shrink: 0;
}

.left-nav-logo-text {
    font-size: 22px;
    font-weight: 800;
    color: white;
    letter-spacing: 0.5px;
    font-family: Arial, sans-serif;
}

/* NAV LIST */

.left-nav-items {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 4px;
    padding: 0 12px;
    flex: 1;
}

/* NAV ITEM */

.left-nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 11px 14px;
    border-radius: 10px;
    color: rgba(255, 255, 255, 0.55);
    font-size: 15px;
    font-weight: 500;
    font-family: Arial, sans-serif;
    cursor: default;
    transition: background 0.18s ease, color 0.18s ease, transform 0.15s ease;
    position: relative;
    user-select: none;
}

/* ACTIVE */

.left-nav-active {
    background: rgba(255, 255, 255, 0.10);
    color: white;
    cursor: default;
    box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.09);
}

/* ACTIVE accent bar */

.left-nav-active::before {
    content: "";
    position: absolute;
    left: -12px;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 60%;
    background: rgba(255, 255, 255, 0.7);
    border-radius: 0 3px 3px 0;
}

/* DISABLED */

.left-nav-disabled {
    opacity: 0.45;
    cursor: not-allowed;
}

.left-nav-disabled:hover {
    background: rgba(255, 255, 255, 0.05);
    color: rgba(255, 255, 255, 0.65);
    transform: translateX(3px);
    opacity: 0.65;
}

/* COMING SOON tooltip */

.left-nav-disabled::after {
    content: attr(data-soon);
    position: absolute;
    left: calc(100% + 12px);
    top: 50%;
    transform: translateY(-50%) translateX(-4px);
    background: rgba(20, 26, 45, 0.96);
    color: rgba(255, 255, 255, 0.8);
    font-size: 12px;
    font-weight: 600;
    padding: 5px 10px;
    border-radius: 7px;
    white-space: nowrap;
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.18s ease, transform 0.18s ease;
    border: 1px solid rgba(255, 255, 255, 0.1);
    z-index: 200;
}

.left-nav-disabled:hover::after {
    opacity: 1;
    transform: translateY(-50%) translateX(0);
}

/* ICON */

.left-nav-icon {
    width: 18px;
    height: 18px;
    flex-shrink: 0;
    opacity: 0.85;
}

/* ACTIVE — pure white text + icon (inactive items unchanged) */
/* Specificity (0,2,0) to override `a.left-nav-item { color: inherit }` (0,1,1).
   The icon uses stroke="currentColor", so pure-white text makes it white too. */

.left-nav-item.left-nav-active {
    color: #fff;
}

.left-nav-item.left-nav-active .left-nav-icon {
    opacity: 1;
}