/* ====================================================================
   AgeDateTools - Main Stylesheet
   Modern, Fast, Accessible Design System (Light & Dark Theme)
   ==================================================================== */

:root {
    /* Color Palette - Light Mode Default */
    --color-bg: #f8fafc;
    --color-surface: #ffffff;
    --color-surface-hover: #f1f5f9;
    --color-surface-alt: #f1f5f9;
    --color-border: #e2e8f0;
    --color-border-hover: #cbd5e1;

    --color-text-primary: #0f172a;
    --color-text-secondary: #475569;
    --color-text-muted: #64748b;
    --color-text-inverse: #ffffff;

    --color-primary: #2563eb;
    --color-primary-hover: #1d4ed8;
    --color-primary-subtle: #eff6ff;
    --color-primary-border: #bfdbfe;

    --color-success: #16a34a;
    --color-success-bg: #f0fdf4;
    --color-warning: #d97706;
    --color-warning-bg: #fffbeb;
    --color-info: #0284c7;
    --color-info-bg: #f0f9ff;

    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);

    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-full: 9999px;

    --container-max: 1200px;
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --transition: 0.2s ease-in-out;
}

[data-theme="dark"] {
    --color-bg: #090d16;
    --color-surface: #111827;
    --color-surface-hover: #1f2937;
    --color-surface-alt: #172033;
    --color-border: #1f293d;
    --color-border-hover: #334155;

    --color-text-primary: #f8fafc;
    --color-text-secondary: #94a3b8;
    --color-text-muted: #64748b;
    --color-text-inverse: #0f172a;

    --color-primary: #3b82f6;
    --color-primary-hover: #60a5fa;
    --color-primary-subtle: #172554;
    --color-primary-border: #1e3a8a;

    --color-success: #22c55e;
    --color-success-bg: #052e16;
    --color-warning: #f59e0b;
    --color-warning-bg: #451a03;
    --color-info: #38bdf8;
    --color-info-bg: #082f49;

    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.3);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.4);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.5);
}

/* Base Reset */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-sans);
    background-color: var(--color-bg);
    color: var(--color-text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color var(--transition), color var(--transition);
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition);
}

a:hover {
    color: var(--color-primary-hover);
}

img, svg {
    display: block;
    max-width: 100%;
}

ul, ol {
    list-style: none;
}

button, input, select, textarea {
    font: inherit;
    color: inherit;
}

/* Accessibility Skip Link */
.skip-link {
    position: absolute;
    top: -9999px;
    left: 20px;
    background: var(--color-primary);
    color: #ffffff;
    padding: 10px 18px;
    border-radius: var(--radius-sm);
    z-index: 9999;
    font-weight: 600;
}
.skip-link:focus {
    top: 20px;
}

/* Layout Container */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 24px;
}

.main-content {
    flex: 1 0 auto;
    padding-bottom: 60px;
}

/* ====================================================================
   Header & Navigation
   ==================================================================== */
.site-header {
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

.header-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.brand-link {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
}

.brand-icon {
    display: flex;
    align-items: center;
    justify-content: center;
}

.brand-details {
    display: flex;
    flex-direction: column;
}

.brand-title {
    font-size: 1.35rem;
    font-weight: 800;
    color: var(--color-text-primary);
    letter-spacing: -0.5px;
    line-height: 1.2;
}

.brand-tagline {
    font-size: 0.72rem;
    font-weight: 600;
    color: var(--color-text-muted);
    letter-spacing: 0.5px;
    text-transform: uppercase;
}

/* Nav Menu */
.site-nav .nav-list {
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 8px 14px;
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--color-text-secondary);
    border-radius: var(--radius-sm);
    transition: background-color var(--transition), color var(--transition);
}

.nav-link:hover, .nav-link.active {
    color: var(--color-primary);
    background-color: var(--color-primary-subtle);
}

/* Dropdown Menu */
.nav-item.dropdown {
    position: relative;
}

.dropdown-chevron {
    transition: transform var(--transition);
}

.nav-item.dropdown:hover .dropdown-chevron,
.nav-item.dropdown:focus-within .dropdown-chevron {
    transform: rotate(180deg);
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 240px;
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 8px;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(8px);
    transition: opacity var(--transition), transform var(--transition), visibility var(--transition);
    z-index: 1010;
}

.nav-item.dropdown:hover .dropdown-menu,
.nav-item.dropdown:focus-within .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-item {
    display: block;
    padding: 10px 14px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-text-primary);
    border-radius: var(--radius-sm);
    transition: background-color var(--transition), color var(--transition);
}

.dropdown-item:hover {
    background-color: var(--color-primary-subtle);
    color: var(--color-primary);
}

.dropdown-divider {
    height: 1px;
    background-color: var(--color-border);
    margin: 6px 0;
}

.dropdown-view-all {
    font-weight: 700;
    color: var(--color-primary);
}

/* Header Action Controls */
.header-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.theme-toggle-btn {
    background: var(--color-surface-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    width: 42px;
    height: 42px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--color-text-secondary);
    transition: background-color var(--transition), border-color var(--transition), color var(--transition);
}

.theme-toggle-btn:hover {
    color: var(--color-primary);
    border-color: var(--color-primary);
}

[data-theme="light"] .theme-toggle-btn .sun-icon {
    display: block;
}
[data-theme="light"] .theme-toggle-btn .moon-icon {
    display: none;
}
[data-theme="dark"] .theme-toggle-btn .sun-icon {
    display: none;
}
[data-theme="dark"] .theme-toggle-btn .moon-icon {
    display: block;
}

.mobile-menu-toggle {
    display: none;
    background: var(--color-surface-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    width: 42px;
    height: 42px;
    padding: 10px;
    cursor: pointer;
    flex-direction: column;
    justify-content: space-around;
}

.hamburger-bar {
    width: 100%;
    height: 2px;
    background-color: var(--color-text-primary);
    border-radius: 2px;
    transition: transform var(--transition), opacity var(--transition);
}

/* ====================================================================
   Breadcrumbs
   ==================================================================== */
.breadcrumbs {
    padding: 16px 0;
    font-size: 0.88rem;
    color: var(--color-text-muted);
}

.breadcrumb-list {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 8px;
}

.breadcrumb-item {
    display: flex;
    align-items: center;
    gap: 8px;
}

.breadcrumb-item:not(:last-child)::after {
    content: "/";
    color: var(--color-text-muted);
}

.breadcrumb-item a {
    color: var(--color-text-secondary);
}

.breadcrumb-item a:hover {
    color: var(--color-primary);
}

.breadcrumb-item.active {
    color: var(--color-text-primary);
    font-weight: 600;
}

/* ====================================================================
   Author Card Component
   ==================================================================== */
.author-box {
    display: flex;
    align-items: center;
    gap: 20px;
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 24px;
    margin: 40px 0;
    box-shadow: var(--shadow-sm);
}

.author-avatar {
    border-radius: 50%;
    box-shadow: var(--shadow-sm);
    flex-shrink: 0;
}

.author-meta-header {
    margin-bottom: 6px;
}

.author-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    font-weight: 700;
    color: var(--color-primary);
}

.author-name {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--color-text-primary);
}

.author-bio {
    font-size: 0.92rem;
    color: var(--color-text-secondary);
    line-height: 1.5;
    margin-bottom: 10px;
}

.author-dates {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    font-size: 0.82rem;
    color: var(--color-text-muted);
}

.author-dates span {
    display: flex;
    align-items: center;
    gap: 6px;
}

/* ====================================================================
   Ad Unit Component (Separated strictly from Calculator controls)
   ==================================================================== */
.ad-unit-wrapper {
    margin: 32px auto;
    max-width: 100%;
    border: 1px dashed var(--color-border);
    border-radius: var(--radius-md);
    background-color: var(--color-surface-alt);
    padding: 12px;
    text-align: center;
    overflow: hidden;
}

.ad-unit-header {
    margin-bottom: 8px;
}

.ad-label {
    display: inline-block;
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--color-text-muted);
    font-weight: 600;
}

.ad-unit-body {
    min-height: 90px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* ====================================================================
   Footer Styles
   ==================================================================== */
.site-footer {
    background-color: var(--color-surface);
    border-top: 1px solid var(--color-border);
    margin-top: auto;
}

.footer-top-strip {
    height: 4px;
    background: linear-gradient(90deg, #2563eb, #38bdf8, #2563eb);
}

.footer-container {
    padding-top: 48px;
    padding-bottom: 32px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 14px;
}

.footer-brand-name {
    font-size: 1.25rem;
    font-weight: 800;
    color: var(--color-text-primary);
}

.footer-desc {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    line-height: 1.6;
    margin-bottom: 20px;
}

.footer-badges {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.badge-item {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.78rem;
    font-weight: 600;
    padding: 4px 10px;
    background-color: var(--color-surface-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-full);
    color: var(--color-text-secondary);
}

.footer-heading {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--color-text-primary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 16px;
}

.footer-links li {
    margin-bottom: 10px;
}

.footer-links a {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    transition: color var(--transition);
}

.footer-links a:hover {
    color: var(--color-primary);
}

.footer-bottom {
    border-top: 1px solid var(--color-border);
    padding-top: 24px;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

/* ====================================================================
   Responsive Styles
   ==================================================================== */
@media (max-width: 992px) {
    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 32px;
    }
}

@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: flex;
    }

    .site-nav {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        right: 0;
        background-color: var(--color-surface);
        border-bottom: 1px solid var(--color-border);
        padding: 16px 24px;
        box-shadow: var(--shadow-lg);
    }

    .site-nav.open {
        display: block;
    }

    .site-nav .nav-list {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }

    .dropdown-menu {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        border: none;
        background: var(--color-surface-alt);
        margin-top: 6px;
        width: 100%;
    }

    .footer-grid {
        grid-template-columns: 1fr;
    }

    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }

    .author-box {
        flex-direction: column;
        text-align: center;
    }

    .author-dates {
        justify-content: center;
    }
}