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

:root {
    --red: #DC2626;
    --red-dark: #B91C1C;
    --red-light: #FEF2F2;
    --white: #FFFFFF;
    --gray-50: #F9FAFB;
    --gray-100: #F3F4F6;
    --gray-200: #E5E7EB;
    --gray-300: #D1D5DB;
    --gray-400: #9CA3AF;
    --gray-500: #6B7280;
    --gray-600: #4B5563;
    --gray-700: #374151;
    --gray-800: #1F2937;
    --gray-900: #111827;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1), 0 4px 6px rgba(0,0,0,0.05);
    --shadow-xl: 0 20px 25px rgba(0,0,0,0.1), 0 10px 10px rgba(0,0,0,0.04);
    --radius: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
}

html { scroll-behavior: smooth; }

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    color: var(--gray-800);
    line-height: 1.6;
    background: var(--white);
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1120px;
    margin: 0 auto;
    padding: 0 24px;
}

.text-red { color: var(--red); }

/* === Buttons === */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: var(--radius);
    font-weight: 600;
    font-size: 14px;
    text-decoration: none;
    border: 2px solid transparent;
    cursor: pointer;
    transition: all 0.2s;
    white-space: nowrap;
}

.btn--primary {
    background: var(--red);
    color: var(--white);
    border-color: var(--red);
}
.btn--primary:hover { background: var(--red-dark); border-color: var(--red-dark); }

.btn--outline {
    background: transparent;
    color: var(--gray-700);
    border-color: var(--gray-300);
}
.btn--outline:hover { border-color: var(--gray-500); color: var(--gray-900); }

.btn--lg { padding: 14px 28px; font-size: 16px; border-radius: var(--radius-lg); }
.btn--full { width: 100%; justify-content: center; }

/* === Navigation === */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--gray-100);
}

.nav__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.nav__logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    font-weight: 700;
    font-size: 18px;
    color: var(--gray-900);
}

.nav__logo-img { width: 32px; height: 32px; }

.nav__links {
    display: flex;
    gap: 32px;
}

.nav__link {
    text-decoration: none;
    color: var(--gray-600);
    font-size: 14px;
    font-weight: 500;
    transition: color 0.2s;
}
.nav__link:hover { color: var(--gray-900); }

.nav__burger {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}
.nav__burger span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--gray-700);
    border-radius: 2px;
    transition: all 0.3s;
}

/* === Hero === */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(135deg, var(--white) 0%, var(--red-light) 100%);
}

.hero__inner {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.hero__badge {
    display: inline-block;
    padding: 6px 14px;
    background: var(--red-light);
    color: var(--red);
    font-size: 13px;
    font-weight: 600;
    border-radius: 20px;
    margin-bottom: 20px;
    border: 1px solid rgba(220, 38, 38, 0.15);
}

.hero__title {
    font-size: 48px;
    font-weight: 800;
    line-height: 1.15;
    color: var(--gray-900);
    margin-bottom: 20px;
}

.hero__subtitle {
    font-size: 18px;
    color: var(--gray-600);
    line-height: 1.7;
    margin-bottom: 32px;
    max-width: 520px;
}

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

.hero__stats {
    display: flex;
    gap: 48px;
}

.hero__stat { text-align: center; }

.hero__stat-number {
    display: block;
    font-size: 28px;
    font-weight: 800;
    color: var(--gray-900);
}

.hero__stat-label {
    font-size: 13px;
    color: var(--gray-500);
    font-weight: 500;
}

/* === Phone Mockup === */
.phone-mockup {
    width: 300px;
    margin: 0 auto;
    background: var(--gray-900);
    border-radius: 36px;
    padding: 12px;
    box-shadow: var(--shadow-xl);
}

.phone-mockup__screen {
    background: var(--white);
    border-radius: 26px;
    overflow: hidden;
    min-height: 480px;
}

.chat-demo { display: flex; flex-direction: column; height: 100%; }

.chat-demo__header {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 14px 16px;
    background: var(--gray-50);
    border-bottom: 1px solid var(--gray-100);
}

.chat-demo__avatar-img {
    width: 32px;
    height: 32px;
    border-radius: 50%;
}

.chat-demo__name {
    font-weight: 600;
    font-size: 14px;
    color: var(--gray-800);
}

.chat-demo__messages { padding: 16px; flex: 1; }

.chat-demo__msg { margin-bottom: 10px; }

.chat-demo__bubble {
    display: inline-block;
    padding: 10px 14px;
    border-radius: 14px;
    font-size: 13px;
    line-height: 1.5;
    max-width: 90%;
    background: var(--gray-100);
    color: var(--gray-800);
}

.chat-demo__bubble--user {
    background: #0088cc;
    color: white;
    float: right;
}

.chat-demo__bubble--success {
    background: #DCFCE7;
    color: #166534;
}

.chat-demo__options {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 10px;
}

.chat-demo__option {
    padding: 6px 12px;
    background: var(--gray-100);
    border-radius: 8px;
    font-size: 12px;
    color: var(--gray-700);
}

.chat-demo__option--correct {
    background: #DCFCE7;
    color: #166534;
    font-weight: 600;
}

/* === Section Header === */
.section-header {
    text-align: center;
    margin-bottom: 56px;
}

.section-title {
    font-size: 36px;
    font-weight: 800;
    color: var(--gray-900);
    margin-bottom: 16px;
}

.section-subtitle {
    font-size: 17px;
    color: var(--gray-500);
    max-width: 600px;
    margin: 0 auto;
}

/* === Features === */
.features {
    padding: 96px 0;
}

.features__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.feature-card {
    padding: 32px;
    border-radius: var(--radius-xl);
    border: 1px solid var(--gray-100);
    transition: all 0.3s;
    background: var(--white);
}
.feature-card:hover {
    border-color: var(--gray-200);
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

.feature-card__icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-lg);
    background: var(--gray-50);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    color: var(--gray-700);
}

.feature-card__icon--red {
    background: var(--red-light);
    color: var(--red);
}

.feature-card__title {
    font-size: 18px;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 10px;
}

.feature-card__text {
    font-size: 14px;
    color: var(--gray-500);
    line-height: 1.7;
}

/* === How It Works === */
.how-it-works {
    padding: 96px 0;
    background: var(--gray-50);
}

.steps {
    display: flex;
    flex-direction: column;
    gap: 32px;
    max-width: 640px;
    margin: 0 auto;
}

.step {
    display: flex;
    gap: 24px;
    align-items: flex-start;
}

.step__number {
    width: 48px;
    height: 48px;
    min-width: 48px;
    border-radius: 50%;
    background: var(--red);
    color: var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 20px;
}

.step__title {
    font-size: 20px;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 6px;
}

.step__text {
    font-size: 15px;
    color: var(--gray-500);
    line-height: 1.7;
}

/* === Topics === */
.topics {
    padding: 96px 0;
}

.topics__grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
}

.topic-tag {
    padding: 8px 18px;
    background: var(--gray-50);
    border: 1px solid var(--gray-200);
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    color: var(--gray-700);
    transition: all 0.2s;
}
.topic-tag:hover {
    background: var(--red-light);
    border-color: var(--red);
    color: var(--red);
}

/* === Pricing === */
.pricing {
    padding: 96px 0;
    background: var(--gray-50);
}

.pricing__grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
    max-width: 720px;
    margin: 0 auto;
}

.pricing-card {
    background: var(--white);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-xl);
    padding: 36px;
    position: relative;
    transition: all 0.3s;
}
.pricing-card:hover { box-shadow: var(--shadow-lg); }

.pricing-card--featured {
    border-color: var(--red);
    border-width: 2px;
    box-shadow: var(--shadow-lg);
}

.pricing-card__badge {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--red);
    color: white;
    padding: 4px 16px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}

.pricing-card__header { margin-bottom: 28px; }

.pricing-card__name {
    font-size: 18px;
    font-weight: 600;
    color: var(--gray-600);
    margin-bottom: 8px;
}

.pricing-card__amount {
    font-size: 42px;
    font-weight: 800;
    color: var(--gray-900);
}

.pricing-card__period {
    font-size: 14px;
    color: var(--gray-400);
    margin-top: 4px;
}

.pricing-card__features {
    list-style: none;
    margin-bottom: 28px;
}

.pricing-card__feature {
    padding: 8px 0;
    font-size: 14px;
    color: var(--gray-700);
    display: flex;
    align-items: center;
    gap: 10px;
}

.pricing-card__feature--yes::before {
    content: '';
    width: 18px;
    height: 18px;
    min-width: 18px;
    border-radius: 50%;
    background: #DCFCE7 url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2316a34a' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='20 6 9 17 4 12'/%3E%3C/svg%3E") center/12px no-repeat;
}

.pricing-card__feature--no {
    color: var(--gray-400);
}

.pricing-card__feature--no::before {
    content: '';
    width: 18px;
    height: 18px;
    min-width: 18px;
    border-radius: 50%;
    background: var(--gray-100) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='10' viewBox='0 0 24 24' fill='none' stroke='%239ca3af' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cline x1='18' y1='6' x2='6' y2='18'/%3E%3Cline x1='6' y1='6' x2='18' y2='18'/%3E%3C/svg%3E") center/10px no-repeat;
}

/* === FAQ === */
.faq {
    padding: 96px 0;
}

.faq__list {
    max-width: 700px;
    margin: 0 auto;
}

.faq__item {
    border-bottom: 1px solid var(--gray-200);
}

.faq__question {
    padding: 20px 0;
    font-size: 16px;
    font-weight: 600;
    color: var(--gray-800);
    cursor: pointer;
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.faq__question::-webkit-details-marker { display: none; }

.faq__question::after {
    content: '+';
    font-size: 24px;
    font-weight: 300;
    color: var(--gray-400);
    transition: transform 0.2s;
}

.faq__item[open] .faq__question::after {
    content: '-';
}

.faq__answer {
    padding: 0 0 20px;
    font-size: 15px;
    color: var(--gray-500);
    line-height: 1.7;
}

/* === CTA === */
.cta {
    padding: 96px 0;
    background: var(--gray-900);
}

.cta__inner {
    text-align: center;
    max-width: 560px;
    margin: 0 auto;
}

.cta__title {
    font-size: 32px;
    font-weight: 800;
    color: var(--white);
    margin-bottom: 16px;
}

.cta__text {
    font-size: 17px;
    color: var(--gray-400);
    margin-bottom: 32px;
}

/* === Footer === */
.footer {
    padding: 32px 0;
    border-top: 1px solid var(--gray-100);
}

.footer__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
}

.footer__brand {
    display: flex;
    align-items: center;
    gap: 10px;
}

.footer__logo-img {
    width: 28px;
    height: 28px;
    border-radius: 6px;
}

.footer__name {
    font-weight: 700;
    font-size: 15px;
    color: var(--gray-900);
}

.footer__links {
    display: flex;
    gap: 24px;
}

.footer__links a {
    text-decoration: none;
    color: var(--gray-500);
    font-size: 14px;
    transition: color 0.2s;
}
.footer__links a:hover { color: var(--gray-800); }

.footer__copy {
    font-size: 13px;
    color: var(--gray-400);
}

/* === Mobile === */
@media (max-width: 768px) {
    .nav__links, .nav__cta { display: none; }
    .nav__burger { display: flex; }

    .nav__links.active {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 64px;
        left: 0;
        right: 0;
        background: white;
        padding: 20px 24px;
        border-bottom: 1px solid var(--gray-200);
        box-shadow: var(--shadow-lg);
        gap: 16px;
    }

    .hero { padding: 100px 0 60px; }
    .hero__inner { grid-template-columns: 1fr; gap: 40px; text-align: center; }
    .hero__title { font-size: 32px; }
    .hero__subtitle { margin: 0 auto 24px; font-size: 16px; }
    .hero__actions { justify-content: center; flex-wrap: wrap; }
    .hero__stats { justify-content: center; }
    .hero__visual { order: -1; }
    .phone-mockup { width: 260px; }

    .section-title { font-size: 28px; }
    .features__grid { grid-template-columns: 1fr; }
    .pricing__grid { grid-template-columns: 1fr; }

    .footer__inner { flex-direction: column; text-align: center; }
}

@media (max-width: 480px) {
    .hero__title { font-size: 28px; }
    .hero__actions { flex-direction: column; align-items: center; }
    .hero__stats { flex-direction: column; gap: 16px; }
    .phone-mockup { width: 240px; }
}