/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #737373;
    --secondary-color: #525252;
    --accent-color: #a3a3a3;
    --text-dark: #e5e5e5;
    --text-light: #a3a3a3;
    --text-white: #f5f5f5;
    --bg-dark: #0a0a0a;
    --bg-darker: #000000;
    --bg-light: #171717;
    --bg-card: #171717;
    --border-color: #262626;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.5);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.6);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.7);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.8);
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-darker);
}

/* Mobile-first Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 { font-size: 2rem; }
h2 { font-size: 1.75rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

p {
    margin-bottom: 1rem;
    color: var(--text-light);
}

/* Buttons (BEM) */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    text-align: center;
    text-decoration: none;
    border-radius: 0.5rem;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn--primary {
    background-color: var(--primary-color);
    color: var(--text-white);
    box-shadow: var(--shadow-md);
}

.btn--primary:hover {
    background-color: var(--secondary-color);
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

/* Section Styles (BEM) */
.section__title {
    text-align: center;
    font-size: 2rem;
    color: var(--text-dark);
    margin-bottom: 3rem;
    position: relative;
}

.section__title::after {
    content: '';
    position: absolute;
    bottom: -0.5rem;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background-color: var(--accent-color);
    border-radius: 2px;
}

/* Screen reader only utility */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Tablet Styles */
@media (min-width: 768px) {
    h1 { font-size: 2.5rem; }
    h2 { font-size: 2rem; }
}

/* Desktop Styles */
@media (min-width: 1024px) {
    h1 { font-size: 3rem; }
    h2 { font-size: 2.5rem; }
}