:root {
    --bg-body: #0a0a0a;
    --bg-card: #141414;
    --bg-surface: #1f1f1f;
    
    --brand-primary: #FFD700;
    --brand-hover: #E6C200;
    
    --text-main: #FFFFFF;
    --text-muted: #A3A3A3;
    
    --container-width: 1100px;
    --header-height: 80px;
    --radius-soft: 12px;
    --radius-pill: 50px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    background-color: var(--bg-body);
    color: var(--text-main);
    font-family: 'Montserrat', sans-serif;
    line-height: 1.8;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    overflow-x: hidden;
}

h1, h2, h3 {
    font-weight: 800;
    letter-spacing: -0.03em;
    line-height: 1.2;
    color: var(--text-main);
}

a { text-decoration: none; color: inherit; transition: all 0.3s ease; }

.main-header {
    background-color: rgba(10, 10, 10, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    position: sticky;
    top: 0;
    z-index: 1000;
    height: var(--header-height);
    display: flex;
    align-items: center;
}

.navbar {
    width: 100%;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 900;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-main);
    border-left: 4px solid var(--brand-primary);
    padding-left: 15px;
}

.nav-links {
    display: flex;
    gap: 3rem;
    list-style: none;
}

.nav-links a {
    font-size: 0.9rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-muted);
    position: relative;
}

.nav-links a:hover, .nav-links a.active {
    color: var(--brand-primary);
}

.nav-links a::after {
    content: '';
    position: absolute;
    width: 0%;
    height: 2px;
    bottom: -5px;
    left: 0;
    background-color: var(--brand-primary);
    transition: width 0.3s ease;
}
.nav-links a:hover::after { width: 100%; }

.app-container {
    width: 100%;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 4rem 2rem;
    flex: 1;
}

.hero-section {
    padding: 4rem 0 6rem;
    text-align: left;
    max-width: 800px;
}

.hero-title {
    font-size: 3.5rem;
    margin-bottom: 1.5rem;
}

.hero-title span {
    color: var(--brand-primary);
}

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--text-muted);
    margin-bottom: 3rem;
    max-width: 600px;
    font-weight: 400;
}

.features-grid, .tests-grid, .tips-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
    gap: 2.5rem;
}

.test-card, .feature-card, .tip-card {
    background-color: var(--bg-card);
    border: 1px solid rgba(255, 255, 255, 0.03);
    padding: 2.5rem;
    border-radius: var(--radius-soft);
    transition: transform 0.3s ease, border-color 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: flex-start;
}

.test-card:hover, .feature-card:hover, .tip-card:hover {
    transform: translateY(-8px);
    border-color: var(--brand-primary);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

.test-card h3, .feature-card h3, .tip-card h3 {
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.test-card p, .feature-card p, .tip-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-bottom: 2rem;
    flex-grow: 1;
}

.badge {
    background-color: rgba(255, 255, 255, 0.05);
    color: var(--brand-primary);
    padding: 0.4rem 1rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 1.5rem;
    display: inline-block;
}

.btn-primary, .btn-primary-sm {
    background-color: var(--brand-primary);
    color: #000000;
    font-weight: 700;
    padding: 1rem 2.5rem;
    border-radius: var(--radius-pill);
    border: none;
    cursor: pointer;
    font-size: 1rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.2s, background-color 0.2s;
}

.btn-primary:hover, .btn-primary-sm:hover {
    background-color: var(--brand-hover);
    transform: scale(1.02);
}

.btn-primary-sm {
    padding: 0.8rem 2rem;
    font-size: 0.9rem;
    width: 100%;
}

.btn-outline, .btn-secondary {
    background: transparent;
    border: 2px solid rgba(255, 255, 255, 0.2);
    color: var(--text-main);
    padding: 1rem 2.5rem;
    border-radius: var(--radius-pill);
    font-weight: 600;
    margin-left: 1rem;
}

.btn-outline:hover, .btn-secondary:hover {
    border-color: var(--brand-primary);
    color: var(--brand-primary);
}

.quiz-container {
    background-color: var(--bg-card);
    border-radius: var(--radius-soft);
    padding: 4rem;
    max-width: 900px;
    margin: 2rem auto;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.question-text {
    font-size: 2rem;
    margin-bottom: 3rem;
    line-height: 1.4;
}

.options-grid {
    display: grid;
    gap: 1.2rem;
}

.option-btn {
    background-color: var(--bg-surface);
    border: 2px solid transparent;
    padding: 1.5rem 2rem;
    border-radius: var(--radius-soft);
    color: var(--text-muted);
    font-size: 1.1rem;
    text-align: left;
    cursor: pointer;
    transition: all 0.2s;
}

.option-btn:hover {
    background-color: rgba(255, 255, 255, 0.05);
    color: var(--text-main);
    transform: translateX(10px);
}

.option-btn.selected {
    border-color: var(--brand-primary);
    background-color: rgba(255, 215, 0, 0.05);
    color: var(--brand-primary);
    font-weight: 700;
}

.progress-track {
    background-color: rgba(255, 255, 255, 0.1);
    height: 4px;
    width: 100%;
    margin-bottom: 3rem;
    border-radius: 2px;
}

.progress-fill {
    background-color: var(--brand-primary);
    height: 100%;
    width: 0%;
    transition: width 0.4s ease;
}

.main-footer {
    background-color: var(--bg-card);
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    padding: 4rem 2rem;
    text-align: center;
    color: var(--text-muted);
    margin-top: auto;
}

.main-footer p {
    font-size: 0.9rem;
    opacity: 0.7;
}

.hidden { display: none !important; }
.fade-in-up { animation: fadeInUp 0.8s cubic-bezier(0.16, 1, 0.3, 1); }
.fade-in { animation: fadeIn 0.8s ease; }

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}
@keyframes fadeIn {
    from { opacity: 0; } to { opacity: 1; }
}

.spinner {
    width: 40px; height: 40px;
    border: 3px solid rgba(255,255,255,0.1);
    border-top-color: var(--brand-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin: 0 auto 1.5rem;
}
@keyframes spin { 100% { transform: rotate(360deg); } }

@media (max-width: 768px) {
    .hero-title { font-size: 2.5rem; }
    .quiz-container { padding: 2rem; }
    .navbar { padding: 0 1rem; }
    .nav-links { gap: 1.5rem; }
}