/**
 * Harith Design System - Base Styles
 * Version: 1.0.0
 * 
 * Resets, typography, and foundational layout styles.
 * Depends on tokens.css for CSS variables.
 */

/* ===================================
   CSS Reset & Base
   =================================== */
*, *::before, *::after {
    box-sizing: border-box;
}

html {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: var(--line-height-normal);
    color: var(--shell-text-light);
    background: var(--shell-bg-light);
    margin: 0;
    padding: 0;
    min-height: 100vh;
    position: relative;
    transition: background 0.3s ease, color 0.3s ease;
}

body.dark-mode {
    background: var(--shell-bg-dark);
    color: var(--shell-text-dark);
}

/* ===================================
   Main Layout
   =================================== */
main {
    width: 100%;
    margin: 0 auto;
    
    /* Fixed Header/Footer Offsets */
    padding-top: var(--header-height);
    padding-bottom: var(--footer-height);
    padding-left: var(--main-horizontal-padding);
    padding-right: var(--main-horizontal-padding);
    
    /* Full Viewport Height to ensure centering and background coverage */
    min-height: 100vh;
    
    /* Center Content */
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    
    background: transparent;
}

.main-center {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 100%;
}

/* ===================================
   Typography
   =================================== */
h1, h2, h3, h4, h5, h6 {
    margin: 0 0 var(--spacing-md) 0;
    font-weight: var(--font-weight-semibold);
    line-height: var(--line-height-tight);
    color: var(--color-text-primary);
}

body.dark-mode h1,
body.dark-mode h2,
body.dark-mode h3,
body.dark-mode h4,
body.dark-mode h5,
body.dark-mode h6 {
    color: var(--color-text-primary-dark);
}

h1 { font-size: var(--font-size-3xl); letter-spacing: 0.5px; }
h2 { font-size: var(--font-size-2xl); }
h3 { font-size: var(--font-size-xl); }
h4, h5, h6 { font-size: var(--font-size-lg); }

p {
    margin: 0 0 var(--spacing-md) 0;
    color: var(--color-text-secondary);
}

body.dark-mode p {
    color: var(--color-text-secondary-dark);
}

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

a:hover, a:focus-visible {
    opacity: 0.75;
}

body.dark-mode a {
    color: var(--color-primary-dark);
}

/* ===================================
   Utility Classes
   =================================== */
.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;
}

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

/* ===================================
   Focus Styles
   =================================== */
:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

body.dark-mode :focus-visible {
    outline-color: var(--color-primary-dark);
}

/* ===================================
   Animations
   =================================== */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideUp {
    from { transform: translateY(50px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

@keyframes slideDown {
    from { transform: translateY(-50px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

/* ===================================
   Responsive
   =================================== */
@media (max-width: 768px) {
    :root {
        --main-horizontal-padding: 1rem;
        --font-size-3xl: 1.75rem;
        --font-size-2xl: 1.375rem;
    }
}