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

/* ===== CUSTOM PROPERTIES ===== */
:root {
    --navy: #0D155B;
    --navy-dark: #0a1048;
    --blue: #5A83F9;
    --blue-hover: #4a71e8;
    --green: #34c759;
    --green-hover: #2db850;
    --green-light: #e8f8ec;
    --yellow: #f5a623;
    --yellow-light: #fef6e6;
    --red: #e53e3e;
    --red-light: #fde8e8;
    --bg: #ffffff;
    --bg-light: #f4f6fc;
    --bg-quiz: #f0f4ff;
    --text: #0D155B;
    --text-secondary: #5a6178;
    --text-muted: #8b93a7;
    --border: #e0e4f0;
    --border-light: #eef1f8;
    --shadow: 0 4px 24px rgba(13, 21, 91, 0.08);
    --shadow-lg: 0 8px 40px rgba(13, 21, 91, 0.12);
    --radius: 12px;
    --radius-sm: 8px;
    --radius-lg: 16px;
    --transition: 0.2s ease-in-out;
    --gradient: linear-gradient(135deg, #0D155B 0%, #1a2980 40%, #5A83F9 100%);
}

/* ===== TYPOGRAPHY ===== */
html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    font-size: 16px;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4 {
    line-height: 1.2;
    font-weight: 700;
}

h1 { font-size: 32px; }
h2 { font-size: 24px; }
h3 { font-size: 20px; }
h4 { font-size: 18px; }

p { margin-bottom: 16px; }
p:last-child { margin-bottom: 0; }

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

strong { font-weight: 600; }

/* ===== LAYOUT ===== */
.container {
    max-width: 680px;
    margin: 0 auto;
    padding: 0 20px;
}

.container--wide {
    max-width: 1140px;
}

/* ===== UTILITIES ===== */
.text-center { text-align: center; }
.text-secondary { color: var(--text-secondary); }
.text-muted { color: var(--text-muted); }
.text-sm { font-size: 14px; }
.text-xs { font-size: 12px; }
.mt-8 { margin-top: 8px; }
.mt-16 { margin-top: 16px; }
.mt-24 { margin-top: 24px; }
.mt-32 { margin-top: 32px; }
.mb-8 { margin-bottom: 8px; }
.mb-16 { margin-bottom: 16px; }
.mb-24 { margin-bottom: 24px; }

/* ===== RESPONSIVE ===== */
@media (min-width: 768px) {
    h1 { font-size: 40px; }
    h2 { font-size: 30px; }
    h3 { font-size: 24px; }
    body { font-size: 17px; }
}