/* Reset & Base */
:root {
    --bg-dark: #050505;
    --bg-card: #121212;
    --bg-input: #1e1e1e;
    --text-primary: #ffffff;
    --text-secondary: #a0a0a0;
    --primary-color: #ffffff;
    --primary-hover: #e0e0e0;
    --border-color: #333333;
    --error-color: #ff4d4d;
    --success-color: #00e676;
    --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    --font-body: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-font-smoothing: antialiased;
}

body {
    font-family: var(--font-body);
    background-color: var(--bg-dark);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.2;
}

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

/* Layout Containers */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

.split-layout {
    display: flex;
    min-height: 100vh;
    align-items: center;
    justify-content: space-between;
    gap: 4rem;
    padding: 2rem 5%;
}

.left-panel {
    flex: 1;
    max-width: 600px;
}

.right-panel {
    flex: 0 0 450px;
    width: 450px;
}

/* Hero Section */
.hero-brand {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 4rem;
    display: block;
    color: var(--text-primary);
    text-decoration: none;
}

.hero-title {
    font-size: 4.5rem;
    font-weight: 800;
    margin-bottom: 2rem;
    letter-spacing: -0.02em;
    line-height: 1.1;
}

.hero-description {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    max-width: 80%;
}

/* Cards */
.card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2.5rem;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1rem;
}

/* Forms */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-control {
    width: 100%;
    background-color: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1rem;
    color: var(--text-primary);
    font-size: 1rem;
    transition: border-color 0.2s;
}

.form-control:focus {
    outline: none;
    border-color: #555;
    background-color: #252525;
}

.form-control::placeholder {
    color: #555;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 1rem 2rem;
    font-size: 1rem;
    font-weight: 700;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    transition: all 0.2s ease;
    text-decoration: none;
}

.btn-primary {
    background-color: var(--primary-color);
    color: #000;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
}

.btn-block {
    width: 100%;
    display: flex;
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
}

.btn-outline:hover {
    border-color: var(--text-primary);
    background-color: var(--bg-input);
}

/* Test Interface */
.test-container {
    max-width: 800px;
    margin: 4rem auto;
    padding: 0 1rem;
}

.test-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.progress-indicator {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.question-card {
    background-color: var(--bg-card);
    border-radius: 16px;
    padding: 4rem 2rem;
    text-align: center;
    border: 1px solid var(--border-color);
}

.question-text {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 4rem;
    line-height: 1.4;
}

.answer-options {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    max-width: 400px;
    margin: 0 auto;
}

.answer-btn {
    background-color: var(--bg-input);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 1.5rem;
    border-radius: 12px;
    cursor: pointer;
    font-size: 1.1rem;
    font-weight: 600;
    text-align: left;
    transition: all 0.2s;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.answer-btn:hover {
    background-color: #2a2a2a;
    border-color: #555;
    transform: translateY(-2px);
}

.answer-btn .key-hint {
    background-color: #333;
    padding: 0.2rem 0.6rem;
    border-radius: 4px;
    font-size: 0.8rem;
    color: #888;
}

/* Alerts */
.alert {
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
    font-size: 0.9rem;
}

.alert-error {
    background-color: rgba(255, 77, 77, 0.1);
    color: #ff8080;
    border: 1px solid rgba(255, 77, 77, 0.2);
}

.alert-success {
    background-color: rgba(0, 230, 118, 0.1);
    color: #69f0ae;
    border: 1px solid rgba(0, 230, 118, 0.2);
}

/* Tabs */
.tabs {
    display: flex;
    gap: 1.5rem;
}

.tab-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid transparent;
}

.tab-btn.active {
    color: var(--text-primary);
    border-bottom-color: var(--text-primary);
}

/* Mobile Responsiveness */
@media (max-width: 900px) {
    .split-layout {
        flex-direction: column;
        padding: 2rem 1.5rem;
        gap: 3rem;
    }
    
    .right-panel {
        width: 100%;
        flex: auto;
    }
    
    .hero-title {
        font-size: 3rem;
    }
}