:root {
    --color-primary: #EF5A0B;
    --color-primary-light: #FF7A35;
    --color-primary-dark: #C44700;
    --color-surface: #FFFFFF;
    --color-surface-alt: #FFF7F3;
    --color-text: #1A1A1A;
    --color-text-muted: #666666;
    --color-correct: #22C55E;
    --color-wrong: #EF4444;
    --color-border: #E5E7EB;
    --color-border-light: #F3F4F6;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --shadow-card: 0 2px 12px rgba(0,0,0,0.08);
    --shadow-elevated: 0 4px 20px rgba(0,0,0,0.12);
    --font-body: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --transition: 0.18s ease;
}

* {
    box-sizing: border-box;
}

*::before,
*::after {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-body);
    color: var(--color-text);
    background: var(--color-surface);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
    margin: 0;
    font-weight: 600;
}

h1 {
    font-size: 1.875rem;
    line-height: 1.2;
}

h2 {
    font-size: 1.5rem;
}

p {
    margin: 0;
}

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

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

input, textarea {
    font-family: inherit;
}

#header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: #1A1A1A;
    border-bottom: none;
    padding: 1rem 1.5rem;
}

#header nav {
    display: flex;
    align-items: center;
    gap: 1rem;
    max-width: 1280px;
    margin: 0 auto;
}

#header a {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-weight: 700;
    color: #FFFFFF;
    font-size: 1.25rem;
}

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

#header img {
    height: 3rem;
}

#app {
    min-height: calc(100vh - 60px - 80px);
}

/* Footer */
#footer {
    background: #1A1A1A;
    color: #999999;
    padding: 1.5rem 1rem;
    text-align: center;
    font-size: 0.85rem;
    line-height: 2;
}

#footer a {
    color: #CCCCCC;
    text-decoration: none;
    transition: color var(--transition);
}

#footer a:hover {
    color: #FFFFFF;
}

#footer .footer-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 0.25rem;
    flex-wrap: wrap;
}

.container {
    max-width: 720px;
    margin: 0 auto;
    padding: 0 1rem;
}

.container--wide {
    max-width: 1200px;
}

/* Typography utilities */
.text-muted {
    color: var(--color-text-muted);
}

.text-small {
    font-size: 0.875rem;
}

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

/* Spacing utilities */
.mt-0 { margin-top: 0; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

.gap-1 { gap: 0.5rem; }
.gap-2 { gap: 1rem; }
.gap-3 { gap: 1.5rem; }

.flex {
    display: flex;
}

.flex-col {
    flex-direction: column;
}

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

.flex-between {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.flex-wrap {
    flex-wrap: wrap;
}

/* Static pages (Terms, Privacy) */
.static-page-content h1 {
    font-size: 1.75rem;
}

.static-page-content h2 {
    font-size: 1.05rem;
    margin-top: 2rem;
    margin-bottom: 0.5rem;
    color: var(--color-primary);
}

.static-page-content p {
    margin-bottom: 1rem;
    line-height: 1.8;
    color: var(--color-text-muted);
}

/* Loading skeleton */
@keyframes shimmer {
    0% { background-position: -1000px 0; }
    100% { background-position: 1000px 0; }
}

.skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 1000px 100%;
    animation: shimmer 2s infinite;
}

/* Responsive */
@media (max-width: 640px) {
    h1 {
        font-size: 1.5rem;
    }

    h2 {
        font-size: 1.25rem;
    }
}