/* ==========================================================================
   Base styles & shared components (base.css)
   ========================================================================== */

body {
    font-family: var(--font-primary);
    font-size: 1rem;
    color: var(--color-text);
    background: var(--color-background);
}

html[lang="ar"] body {
    font-family: var(--font-arabic);
    line-height: 1.75;
    letter-spacing: 0;
}

/* ---------- Accessibility helpers ---------- */

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
    border: 0;
}

.skip-link {
    position: absolute;
    inset-inline-start: 1rem;
    top: -3rem;
    z-index: 100;
    background: var(--color-primary);
    color: #fff;
    padding: 0.6rem 1rem;
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-weight: 600;
    transition: top var(--transition-fast);
}

.skip-link:focus {
    top: 0.75rem;
}

:focus-visible {
    outline: 3px solid var(--color-primary-ring);
    outline-offset: 2px;
    border-radius: 2px;
}

::selection {
    background: var(--color-primary-soft);
    color: var(--color-primary-active);
}

/* ---------- Layout ---------- */

.container {
    max-width: var(--container);
    margin-inline: auto;
    padding-inline: clamp(1rem, 4vw, 2rem);
}

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

.section--tight {
    padding-block: clamp(1.5rem, 3.5vw, 2.5rem);
}

.section--alt {
    background: var(--color-surface);
    border-block: 1px solid var(--color-border);
}

.section__title {
    font-size: clamp(1.35rem, 2.6vw, 1.75rem);
    font-weight: 700;
    letter-spacing: -0.015em;
    margin-bottom: 0.4rem;
}

.section__sub {
    color: var(--color-text-muted);
    max-width: 44rem;
    margin-bottom: 1.75rem;
}

.section-head-row {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    align-items: end;
    justify-content: space-between;
    margin-bottom: 1.75rem;
}

.section-head-row .section__title {
    margin-bottom: 0.25rem;
}

.section-head-row .section__sub {
    margin-bottom: 0;
}

/* ---------- Buttons ---------- */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    min-height: var(--control-height);
    padding: 0.6rem 1.35rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 0.975rem;
    text-decoration: none;
    border: 1px solid transparent;
    transition: background-color var(--transition-fast), border-color var(--transition-fast),
        color var(--transition-fast), box-shadow var(--transition-fast);
    cursor: pointer;
}

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

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

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

.btn--ghost {
    background: transparent;
    color: var(--color-primary);
    border-color: var(--color-primary-border);
}

.btn--ghost:hover {
    background: var(--color-primary-soft);
    border-color: var(--color-primary);
}

.btn--outline {
    background: transparent;
    color: var(--color-text);
    border-color: var(--color-border-strong);
}

.btn--outline:hover {
    background: var(--color-surface);
    border-color: var(--color-text-faint);
}

.btn--lg {
    min-height: var(--control-height-lg);
    padding-inline: 1.75rem;
}

/* ---------- Chips ---------- */

.chip-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.chip {
    display: inline-flex;
    align-items: center;
    min-height: 2.25rem;
    padding: 0.3rem 0.9rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-pill);
    background: var(--color-background);
    color: var(--color-text);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    transition: border-color var(--transition-fast), background-color var(--transition-fast);
}

.chip:hover {
    border-color: var(--color-primary);
    background: var(--color-primary-soft);
    color: var(--color-primary-active);
}

/* ---------- Page head (inner pages) ---------- */

.page-head {
    padding: clamp(1.5rem, 4vw, 2.75rem) 0 clamp(1.25rem, 3vw, 2rem);
    background: linear-gradient(180deg, var(--color-surface) 0%, var(--color-background) 100%);
    border-bottom: 1px solid var(--color-border);
}

.page-head__title {
    font-size: clamp(1.7rem, 4.5vw, 2.4rem);
    font-weight: 750;
    letter-spacing: -0.02em;
    margin-top: 0.85rem;
}

.page-head__sub {
    color: var(--color-text-muted);
    max-width: 44rem;
    margin-top: 0.5rem;
}

.page-head__search {
    max-width: 34rem;
    margin-top: 1.25rem;
}

.page-head--calc {
    padding-bottom: clamp(1rem, 2.5vw, 1.5rem);
}

/* ---------- Breadcrumbs ---------- */

.breadcrumbs-nav {
    font-size: 0.875rem;
}

.breadcrumbs {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.35rem;
    padding: 0;
    margin: 0;
    color: var(--color-text-muted);
}

.breadcrumbs__item {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
}

.breadcrumbs__item + .breadcrumbs__item::before {
    content: "/";
    color: var(--color-border-strong);
}

.breadcrumbs__link {
    color: var(--color-text-muted);
    text-decoration: none;
    border-radius: 2px;
}

.breadcrumbs__link:hover {
    color: var(--color-primary);
    text-decoration: underline;
}

.breadcrumbs__item[aria-current="page"] {
    color: var(--color-text);
    font-weight: 550;
}

/* ---------- Prose (content sections) ---------- */

.prose {
    color: var(--color-text);
}

.prose--narrow {
    max-width: var(--container-narrow);
}

.prose h2 {
    font-size: clamp(1.25rem, 2.4vw, 1.5rem);
    font-weight: 700;
    letter-spacing: -0.01em;
    margin: 1.9rem 0 0.75rem;
}

.prose h2:first-child {
    margin-top: 0;
}

.prose p {
    margin-bottom: 1rem;
    color: var(--color-text-muted);
}

.prose p:last-child {
    margin-bottom: 0;
}

.prose ul {
    margin: 0 0 1rem;
    padding-inline-start: 1.35rem;
    color: var(--color-text-muted);
}

.prose li {
    margin-bottom: 0.4rem;
}

.prose strong {
    color: var(--color-text);
    font-weight: 650;
}

.prose a {
    color: var(--color-primary);
    text-decoration: underline;
    text-decoration-color: var(--color-primary-border);
    text-underline-offset: 2px;
}

.prose a:hover {
    text-decoration-color: var(--color-primary);
}

/* ---------- Formula ---------- */

.formula {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 1.1rem 1.25rem;
    margin: 0 0 1rem;
    font-size: 1.05rem;
    font-weight: 550;
    text-align: center;
    line-height: 1.8;
    color: var(--color-text);
    overflow-x: auto;
}

.formula sup {
    font-size: 0.72em;
}

.formula sub {
    font-size: 0.72em;
}

.formula__where-label {
    font-weight: 600;
    color: var(--color-text);
    margin: 0.75rem 0 0.35rem !important;
}

.formula__where {
    list-style: none;
    padding: 0 !important;
    margin: 0 0 1rem !important;
    font-size: 0.925rem;
    color: var(--color-text-muted) !important;
}

.formula__where li {
    padding-inline-start: 1.1rem;
    position: relative;
    margin-bottom: 0.3rem;
}

.formula__where li::before {
    content: "";
    position: absolute;
    inset-inline-start: 0;
    top: 0.62em;
    width: 0.42rem;
    height: 0.42rem;
    border-radius: 50%;
    background: var(--color-primary-border);
}

/* ---------- FAQ ---------- */

.faq-list {
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    background: var(--color-background);
}

.faq {
    border-bottom: 1px solid var(--color-border);
}

.faq:last-child {
    border-bottom: 0;
}

.faq__q {
    list-style: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: 1rem 1.25rem;
    font-weight: 600;
    font-size: 0.975rem;
    transition: background-color var(--transition-fast);
}

.faq__q::-webkit-details-marker {
    display: none;
}

.faq__q:hover {
    background: var(--color-surface);
}

.faq__chev {
    flex: 0 0 auto;
    width: 1.15rem;
    height: 1.15rem;
    color: var(--color-text-faint);
    transition: transform var(--transition-base);
}

.faq[open] .faq__chev {
    transform: rotate(180deg);
}

.faq__a {
    padding: 0 1.25rem 1.15rem;
    color: var(--color-text-muted);
    font-size: 0.95rem;
}

/* ---------- Ad slots ---------- */

.ad-slot {
    display: block;
}

.ad-slot__inner {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-inline: auto;
    max-width: var(--container);
    border: 1px dashed var(--color-border-strong);
    border-radius: var(--radius-md);
    background: #FCFCFD;
    min-height: 6.25rem;      /* reserved space: prevents layout shift when ads load */
}

.ad-slot--rect .ad-slot__inner {
    min-height: 15.625rem;    /* 250px rectangle */
}

.ad-slot__label {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.09em;
    color: var(--color-text-faint);
}

/* ---------- Hero (homepage) ---------- */

.hero {
    background:
        radial-gradient(60rem 24rem at 85% -30%, var(--color-primary-soft) 0%, transparent 60%),
        linear-gradient(180deg, var(--color-surface) 0%, var(--color-background) 100%);
    border-bottom: 1px solid var(--color-border);
}

.hero__inner {
    padding-block: clamp(2.75rem, 8vw, 5.5rem);
    max-width: var(--container-narrow);
    text-align: center;
}

.hero__title {
    font-size: clamp(2rem, 6vw, 3.1rem);
    font-weight: 800;
    letter-spacing: -0.025em;
    line-height: 1.12;
}

.hero__sub {
    margin-top: 0.9rem;
    color: var(--color-text-muted);
    font-size: clamp(1rem, 2.2vw, 1.175rem);
    max-width: 38rem;
    margin-inline: auto;
}

.hero__search {
    max-width: 34rem;
    margin: 1.75rem auto 0;
}

.hero__stats {
    margin-top: 1.1rem;
    font-size: 0.85rem;
    color: var(--color-text-faint);
    font-variant-numeric: tabular-nums;
}

/* ---------- Search box ---------- */

.search-box {
    position: relative;
}

.search-box__field {
    position: relative;
    display: flex;
    align-items: center;
}

.search-box__icon {
    position: absolute;
    inset-inline-start: 0.95rem;
    width: 1.2rem;
    height: 1.2rem;
    color: var(--color-text-faint);
    pointer-events: none;
}

.search-box__input {
    width: 100%;
    min-height: var(--control-height-lg);
    padding-inline: 2.9rem 2.9rem;
    border: 1px solid var(--color-border-strong);
    border-radius: var(--radius-md);
    background: var(--color-background);
    color: var(--color-text);
    font-size: 1rem;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
    -webkit-appearance: none;
    appearance: none;
}

html[dir="rtl"] .search-box__input {
    padding-inline: 2.9rem 2.9rem;
}

.search-box__input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-ring);
}

.search-box__input::-webkit-search-cancel-button,
.search-box__input::-webkit-search-decoration {
    -webkit-appearance: none;
}

.search-box__clear {
    position: absolute;
    inset-inline-end: 0.55rem;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2rem;
    height: 2rem;
    border-radius: 50%;
    color: var(--color-text-faint);
    transition: background-color var(--transition-fast), color var(--transition-fast);
}

.search-box__clear:hover {
    background: var(--color-surface-alt);
    color: var(--color-text);
}

.search-box__clear svg {
    width: 1rem;
    height: 1rem;
}

.search-box__panel {
    position: absolute;
    top: calc(100% + 0.4rem);
    inset-inline: 0;
    z-index: var(--z-search);
    background: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    max-height: min(24rem, 60vh);
    overflow-y: auto;
    padding: 0.35rem;
}

.search-box__hint {
    padding: 0.8rem 0.9rem;
    color: var(--color-text-faint);
    font-size: 0.9rem;
}

.search-box__noresult {
    padding: 0.9rem;
}

.search-box__noresult strong {
    display: block;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 0.2rem;
}

.search-box__noresult span {
    color: var(--color-text-muted);
    font-size: 0.875rem;
}

.search-option {
    display: flex;
    flex-direction: column;
    gap: 0.1rem;
    padding: 0.6rem 0.75rem;
    border-radius: var(--radius-sm);
    text-decoration: none;
    color: var(--color-text);
    cursor: pointer;
}

.search-option:hover,
.search-option.is-active {
    background: var(--color-primary-soft);
}

.search-option__name {
    font-weight: 600;
    font-size: 0.95rem;
}

.search-option__name mark {
    background: transparent;
    color: var(--color-primary);
    font-weight: 750;
    padding: 0;
}

.search-option__meta {
    font-size: 0.8rem;
    color: var(--color-text-faint);
}

.search-option__desc {
    font-size: 0.825rem;
    color: var(--color-text-muted);
    display: -webkit-box;
    -webkit-line-clamp: 1;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* ---------- Features (homepage) ---------- */

.features-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
}

.feature {
    display: flex;
    gap: 0.9rem;
    align-items: flex-start;
}

.feature__icon {
    flex: 0 0 auto;
    width: 2.6rem;
    height: 2.6rem;
    padding: 0.55rem;
    border-radius: var(--radius-md);
    background: var(--color-primary-soft);
    color: var(--color-primary);
}

.feature__title {
    font-size: 1rem;
    font-weight: 650;
    margin-bottom: 0.2rem;
}

.feature__desc {
    color: var(--color-text-muted);
    font-size: 0.925rem;
}

/* ---------- 404 ---------- */

.page-404 {
    padding-block: clamp(3.5rem, 10vw, 6.5rem);
    text-align: center;
}

.page-404__code {
    font-size: clamp(3.5rem, 12vw, 5.5rem);
    font-weight: 800;
    letter-spacing: -0.04em;
    color: var(--color-primary-border);
    line-height: 1;
}

.page-404 h1 {
    margin-top: 0.5rem;
    font-size: clamp(1.5rem, 4vw, 2.1rem);
    font-weight: 750;
    letter-spacing: -0.02em;
}

.page-404__lead {
    margin: 0.9rem auto 0;
    max-width: 34rem;
    color: var(--color-text-muted);
}

.page-404__search {
    max-width: 30rem;
    margin: 1.75rem auto 0;
    text-align: start;
}

.page-404__actions {
    margin-top: 1.5rem;
    display: flex;
    gap: 0.75rem;
    justify-content: center;
    flex-wrap: wrap;
}

.page-404__hint {
    margin-top: 1.75rem;
    color: var(--color-text-faint);
    font-size: 0.9rem;
}

.page-404__hint a {
    color: var(--color-primary);
}

/* ---------- Main ---------- */

.site-main {
    min-height: 60vh;
}