/* --- CSS VARIABLES & RESET --- */
:root {
    --primary-gradient: linear-gradient(135deg, #4A90E2 0%, #50E3C2 100%);
    --primary-color: #4A90E2;
    --secondary-color: #50E3C2;
    --text-dark: #1a1a1a;
    --text-secondary: #6b7280;
    --bg-light: #f9fafb;
    --white: #ffffff;
    --border-color: #e5e7eb;
    --radius: 12px;
    --radius-lg: 16px;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 10px 15px -3px rgba(0, 0, 0, 0.05);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.05), 0 10px 10px -5px rgba(0, 0, 0, 0.02);

    /* Colors for feedback */
    --success-color: #10b981;
    --error-color: #ef4444;
}

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

body {
    font-family: 'Open Sans', sans-serif;
    color: var(--text-dark);
    line-height: 1.6;
    background: var(--white);
    overflow-x: hidden;
}

h1, h2, h3, h4 {
    font-family: 'Montserrat', sans-serif;
    font-weight: 700;
    line-height: 1.2;
}

h1 { font-size: 3rem; }
h2 { font-size: 2.25rem; }
h3 { font-size: 1.25rem; }

a { text-decoration: none; color: inherit; transition: all 0.3s ease; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Brand Gradient Text Style */
.brand-gradient {
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 800;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 28px;
    border-radius: 50px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    border: none;
    transition: all 0.3s ease;
    gap: 8px;
}

.btn-primary {
    background: var(--primary-gradient);
    color: var(--white);
    box-shadow: 0 4px 14px rgba(74, 144, 226, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(74, 144, 226, 0.4);
}

.btn-secondary {
    background: var(--white);
    border: 2px solid var(--border-color);
    color: var(--text-dark);
}

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

.btn-large {
    padding: 16px 32px;
    font-size: 1.125rem;
}

/* Header */
header {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    padding: 16px 0;
}

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

.logo {
    font-size: 1.75rem;
    font-weight: 800;
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo img {
    height: 40px;
    width: auto;
}

.nav-links {
    display: flex;
    gap: 32px;
    align-items: center;
}

.nav-links a {
    font-weight: 500;
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

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

/* Кнопка-CTA в шапке — текст всегда белый */
.nav-links a.btn-primary,
.nav-links a.btn-primary:hover {
    color: var(--white);
}

.mobile-menu-btn {
    display: none;
    font-size: 1.5rem;
    cursor: pointer;
}

/* Hero Section */
.hero {
    padding: 180px 0 120px;
    background: linear-gradient(180deg, #f0f9ff 0%, #ffffff 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 800px;
    height: 800px;
    background: radial-gradient(circle, rgba(74, 144, 226, 0.08) 0%, transparent 70%);
    border-radius: 50%;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-content h1 {
    margin-bottom: 24px;
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 16px;
    display: block;
}

.hero-content p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 32px;
    line-height: 1.7;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    margin-bottom: 48px;
}

.hero-quote {
    font-style: italic;
    color: var(--text-secondary);
    border-left: 3px solid var(--secondary-color);
    padding-left: 20px;
    font-size: 1.0625rem;
    line-height: 1.7;
}

.hero-visual {
    position: relative;
}

.demo-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: 0;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
    overflow: hidden;
}

.demo-header {
    background: var(--bg-light);
    padding: 16px 24px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.demo-session-info {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.demo-mode-badge {
    background: var(--primary-gradient);
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
}

.demo-body {
    padding: 32px;
}

.demo-question {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 24px;
    color: var(--text-dark);
    text-align: center;
}

.demo-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

.demo-option {
    position: relative;
    background: var(--white);
    border: 2px solid var(--border-color);
    border-radius: var(--radius);
    padding: 0;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    aspect-ratio: 1 / 1;
    overflow: hidden;
}

.demo-option:hover {
    border-color: var(--primary-color);
    box-shadow: 0 4px 12px rgba(74, 144, 226, 0.12);
    transform: translateY(-3px);
}

.demo-option img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: var(--radius);
}

/* --- FEEDBACK ICONS STYLES --- */
.feedback-icon {
    position: absolute;
    top: 8px;
    right: 8px;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    font-weight: bold;
    color: white;
    z-index: 2;
    opacity: 0;
    transform: scale(0.5);
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    pointer-events: none;
}

.demo-option.selected-correct .feedback-icon.check {
    background: var(--success-color);
    box-shadow: 0 2px 4px rgba(16, 185, 129, 0.3);
    opacity: 1;
    transform: scale(1);
}

.demo-option.selected-correct {
    border-color: var(--success-color);
    background: #f0fdf4;
    transform: scale(1.05);
}

.demo-option.selected-wrong .feedback-icon.cross {
    background: var(--error-color);
    box-shadow: 0 2px 4px rgba(239, 68, 68, 0.3);
    opacity: 1;
    transform: scale(1);
}

.demo-option.selected-wrong {
    border-color: var(--error-color);
    background: #fef2f2;
    animation: shake 0.5s;
}

@keyframes shake {
    0% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    50% { transform: translateX(5px); }
    75% { transform: translateX(-5px); }
    100% { transform: translateX(0); }
}

/* Sections General */
section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-header h2 {
    margin-bottom: 16px;
}

.section-header p {
    font-size: 1.125rem;
    color: var(--text-secondary);
    max-width: 640px;
    margin: 0 auto;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 24px;
}

/* Cards */
.card {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: 32px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--primary-gradient);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: transparent;
}

.card:hover::before {
    transform: scaleX(1);
}

.card h3 {
    color: var(--text-dark);
    margin-bottom: 12px;
    font-size: 1.25rem;
}

.card p, .card li {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.7;
}

.card-icon {
    font-size: 2.5rem;
    margin-bottom: 20px;
    display: block;
}
/* Иконки-картинки вместо эмодзи */
.card-icon img { width: 56px; height: 56px; object-fit: contain; display: block; }
.set-icon { width: 72px; height: 72px; object-fit: contain; display: block; margin: 0 auto 16px; }

.card ul {
    margin-top: 12px;
}

.card li {
    margin-bottom: 8px;
    padding-left: 20px;
    position: relative;
}

.card li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--secondary-color);
    font-weight: 700;
}

.tag {
    display: inline-block;
    background: linear-gradient(135deg, #e0f2fe 0%, #ccfbf1 100%);
    color: var(--primary-color);
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 0.8125rem;
    font-weight: 600;
    margin: 4px;
}

/* Problems & Advantages */
.problems-section { background: var(--bg-light); }
.advantages-section { background: var(--white); }

/* Process Steps */
.process-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
    margin-top: 48px;
}

.step {
    background: var(--white);
    padding: 32px;
    border-radius: var(--radius-lg);
    text-align: center;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.step:hover {
    box-shadow: var(--shadow);
    transform: translateY(-4px);
}

.step-number {
    background: var(--primary-gradient);
    color: white;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    font-weight: 700;
    font-size: 1.25rem;
}

.step h3 { margin-bottom: 12px; }

/* Pricing */
.pricing-table {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 24px;
    margin-top: 48px;
}

.price-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: 40px 32px;
    border: 2px solid var(--border-color);
    text-align: center;
    position: relative;
    transition: all 0.3s ease;
}

.price-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.price-card.popular {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-lg);
}

.popular-badge {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary-gradient);
    color: white;
    padding: 8px 20px;
    border-radius: 20px;
    font-size: 0.8125rem;
    font-weight: 700;
    letter-spacing: 0.5px;
}

.price-card h3 { margin-bottom: 16px; font-size: 1.5rem; }

.price-amount {
    font-size: 3rem;
    font-weight: 800;
    color: var(--text-dark);
    margin: 24px 0;
    letter-spacing: -0.02em;
}

.price-amount span {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.price-features {
    list-style: none;
    padding: 0;
    margin: 32px 0;
    text-align: left;
}

.price-features li {
    padding: 12px 0;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

.price-features li:last-child { border-bottom: none; }

.price-features li::before {
    content: '✓';
    color: var(--secondary-color);
    font-weight: 700;
    margin-right: 10px;
}

/* Disclaimer */
.disclaimer {
    background: #f8f9fa;
    padding: 48px 0;
    border-top: 1px solid var(--border-color);
}

.disclaimer-text {
    max-width: 900px;
    margin: 0 auto;
    text-align: center;
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

.disclaimer-text strong {
    color: var(--text-dark);
    display: block;
    margin-bottom: 12px;
    font-size: 1rem;
}

.disclaimer-box {
    background: white;
    padding: 24px;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    margin-top: 20px;
}

/* CTA */
.cta-section {
    background: linear-gradient(135deg, #f0f9ff 0%, #ecfdf5 100%);
    text-align: center;
    padding: 100px 0;
}

.cta-section h2 { margin-bottom: 20px; }

.cta-section p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 40px;
    max-width: 640px;
    margin-left: auto;
    margin-right: auto;
}

/* Footer */
footer {
    background: var(--text-dark);
    color: var(--white);
    padding: 80px 0 32px;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 64px;
    margin-bottom: 48px;
}

.footer-content img {
max-height: 50px;
    margin: 0 0 15px 0;
}

.footer-col h4 {
    color: var(--white);
    margin-bottom: 24px;
    font-size: 1.125rem;
}

.footer-col p {
    color: #9ca3af;
    line-height: 1.7;
    margin-bottom: 16px;
}

.footer-col ul li { margin-bottom: 12px; }

.footer-col a { color: #9ca3af; font-size: 0.9375rem; }

.footer-col a:hover { color: var(--secondary-color); }

.copyright {
    text-align: center;
    padding-top: 32px;
    border-top: 1px solid rgba(255,255,255,0.1);
    color: #6b7280;
    font-size: 0.875rem;
}

/* Responsive */
@media (max-width: 1024px) {
    .hero-grid { grid-template-columns: 1fr; gap: 48px; }
    .hero-content { text-align: center; }
    .hero-buttons { justify-content: center; }
    .hero-quote { margin-left: auto; margin-right: auto; max-width: 640px; }
    .footer-content { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
    h1 { font-size: 2.25rem; }
    h2 { font-size: 1.875rem; }
    .nav-links { display: none; position: absolute; top: 100%; left: 0; width: 100%; background: var(--white); flex-direction: column; padding: 24px; box-shadow: var(--shadow); gap: 16px; }
    .nav-links.active { display: flex; }
    .mobile-menu-btn { display: block; }
    .grid { grid-template-columns: 1fr; }
    .footer-content { grid-template-columns: 1fr; gap: 32px; }
    .hero-buttons { flex-direction: column; }
    .btn-large { width: 100%; }
    .demo-options { gap: 12px; }
}