/* ==========================================================================
   HealthMedHub - Core Design System
   ========================================================================== */

/* ---------- 1. CSS Variables (Design Tokens) ---------- */
:root {
    --color-primary: #0F172A;
    --color-primary-light: #1E293B;
    --color-accent: #0EA5E9;
    --color-accent-hover: #0284C7;
    --color-background: #F8FAFC;
    --color-surface: #FFFFFF;
    --color-border: #E2E8F0;
    --color-text: #0F172A;
    --color-text-muted: #64748B;
    --color-success: #10B981;
    --color-danger: #EF4444;

    --font-heading: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;

    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 2.5rem;
    --space-xl: 4rem;
    --space-2xl: 6rem;

    --container-max: 1200px;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;

    --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(15, 23, 42, 0.08);
    --shadow-lg: 0 10px 15px -3px rgba(15, 23, 42, 0.1);
}

/* ---------- 2. Reset & Base ---------- */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    font-family: var(--font-body);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-background);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.2;
    color: var(--color-primary);
    margin-bottom: var(--space-sm);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }

p { margin-bottom: var(--space-sm); }

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color 0.2s ease;
}

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

img { max-width: 100%; height: auto; display: block; }

/* ---------- 3. Layout Helpers ---------- */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--space-md);
}

.section {
    padding: var(--space-xl) 0;
}

.section-title {
    text-align: center;
    margin-bottom: var(--space-lg);
}

.section-title h2 {
    font-size: 2rem;
    margin-bottom: var(--space-xs);
}

.section-title p {
    color: var(--color-text-muted);
    font-size: 1.125rem;
    max-width: 600px;
    margin: 0 auto;
}

/* ---------- 4. Header & Navigation ---------- */
.site-header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.site-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--font-heading);
    font-weight: 800;
    font-size: 1.25rem;
    color: var(--color-primary);
    text-decoration: none;
}

.site-logo:hover { color: var(--color-primary); }

.site-logo .logo-mark {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background-color: var(--color-accent);
    color: white;
    border-radius: var(--radius-sm);
    font-size: 1.1rem;
    font-weight: 800;
}

.main-nav ul {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    list-style: none;
}

.main-nav a {
    color: var(--color-text);
    font-weight: 500;
    font-size: 0.95rem;
    padding: 0.5rem 0;
    position: relative;
}

.main-nav a:hover { color: var(--color-accent); }

.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--color-primary);
    margin: 5px 0;
    transition: 0.3s;
}

/* ---------- 5. Buttons ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    font-family: var(--font-heading);
    font-weight: 600;
    font-size: 1rem;
    border-radius: var(--radius-sm);
    border: none;
    cursor: pointer;
    transition: all 0.2s ease;
    text-decoration: none;
}

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

.btn-primary:hover {
    background-color: var(--color-accent-hover);
    color: white;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background-color: transparent;
    color: var(--color-primary);
    border: 1.5px solid var(--color-border);
}

.btn-secondary:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
}

/* ---------- 6. Hero Section ---------- */
.hero {
    padding: var(--space-2xl) 0 var(--space-xl);
    background: linear-gradient(180deg, #FFFFFF 0%, #F8FAFC 100%);
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: var(--space-md);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.hero .hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-text-muted);
    max-width: 600px;
    margin: 0 auto var(--space-lg);
}

.hero-actions {
    display: flex;
    gap: var(--space-sm);
    justify-content: center;
    flex-wrap: wrap;
}

/* ---------- 7. Tool Cards Grid ---------- */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-md);
}

.tool-card {
    display: block;
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-md);
    text-decoration: none;
    color: var(--color-text);
    transition: all 0.2s ease;
}

.tool-card:hover {
    border-color: var(--color-accent);
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
    color: var(--color-text);
}

.tool-card .tool-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background-color: #E0F2FE;
    color: var(--color-accent);
    border-radius: var(--radius-sm);
    font-size: 1.5rem;
    margin-bottom: var(--space-sm);
}

.tool-card h3 {
    font-size: 1.125rem;
    margin-bottom: 0.25rem;
}

.tool-card p {
    color: var(--color-text-muted);
    font-size: 0.9rem;
    margin-bottom: 0;
}

/* ---------- 8. Category Cards ---------- */
.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-md);
}

.category-card {
    background-color: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    text-decoration: none;
    color: var(--color-text);
    border: 1px solid var(--color-border);
    transition: all 0.2s ease;
}

.category-card:hover {
    border-color: var(--color-accent);
    box-shadow: var(--shadow-lg);
    color: var(--color-text);
}

.category-card h3 {
    font-size: 1.375rem;
    margin-bottom: var(--space-xs);
}

.category-card p {
    color: var(--color-text-muted);
    margin-bottom: 0;
}

/* ---------- 9. Features ---------- */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: var(--space-md);
}

.feature {
    text-align: center;
    padding: var(--space-md);
}

.feature-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 56px;
    height: 56px;
    background-color: #E0F2FE;
    color: var(--color-accent);
    border-radius: 50%;
    font-size: 1.75rem;
    margin-bottom: var(--space-sm);
}

.feature h3 {
    font-size: 1.125rem;
    margin-bottom: 0.25rem;
}

.feature p {
    color: var(--color-text-muted);
    font-size: 0.95rem;
}

/* ---------- 10. Footer ---------- */
.site-footer {
    background-color: var(--color-primary);
    color: #CBD5E1;
    padding: var(--space-xl) 0 var(--space-md);
    margin-top: var(--space-xl);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: var(--space-lg);
    margin-bottom: var(--space-lg);
}

.footer-brand .site-logo {
    color: white;
    margin-bottom: var(--space-sm);
}

.footer-brand p {
    color: #94A3B8;
    font-size: 0.9rem;
    max-width: 300px;
}

.footer-col h4 {
    color: white;
    font-size: 0.95rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-sm);
}

.footer-col ul {
    list-style: none;
}

.footer-col a {
    color: #94A3B8;
    font-size: 0.9rem;
    display: block;
    padding: 0.3rem 0;
}

.footer-col a:hover { color: white; }

.footer-bottom {
    border-top: 1px solid #1E293B;
    padding-top: var(--space-md);
    text-align: center;
    font-size: 0.85rem;
    color: #64748B;
}

.footer-disclaimer {
    font-size: 0.8rem;
    color: #64748B;
    max-width: 800px;
    margin: var(--space-sm) auto 0;
    line-height: 1.5;
}

/* ---------- 11. Responsive (Mobile-First) ---------- */
@media (max-width: 900px) {
    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 768px) {
    h1 { font-size: 2rem; }
    h2 { font-size: 1.625rem; }
    .hero h1 { font-size: 2.25rem; }
    .hero .hero-subtitle { font-size: 1.05rem; }

    .nav-toggle { display: block; }

    .main-nav {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background-color: var(--color-surface);
        border-bottom: 1px solid var(--color-border);
        box-shadow: var(--shadow-md);
        padding: var(--space-sm) var(--space-md);
    }

    .main-nav.is-open { display: block; }

    .main-nav ul {
        flex-direction: column;
        align-items: flex-start;
        gap: 0;
    }

    .main-nav li {
        width: 100%;
        border-bottom: 1px solid var(--color-border);
    }

    .main-nav a {
        display: block;
        padding: var(--space-sm) 0;
    }
}

@media (max-width: 560px) {
    .footer-grid {
        grid-template-columns: 1fr;
    }
    .hero-actions {
        flex-direction: column;
    }
    .hero-actions .btn {
        width: 100%;
    }
    .section { padding: var(--space-lg) 0; }
}