/* CSS Variables & Reset */
:root {
    --bg-color: #F8F9FA;
    --bg-color-alt: #E9ECEF;
    --text-primary: #2B2D42;
    --text-secondary: #6B7280;
    --brand-primary: #1D3557;
    --brand-accent: #457B9D;
    --brand-hover: #142845;
    
    --border-color: rgba(43, 45, 66, 0.1);
    --border-radius-sm: 8px;
    --border-radius-md: 12px;
    --border-radius-lg: 20px;
    
    --shadow-sm: 0 2px 8px rgba(29, 53, 87, 0.04);
    --shadow-md: 0 8px 24px rgba(29, 53, 87, 0.08);
    --shadow-lg: 0 16px 40px rgba(29, 53, 87, 0.12);
    
    --transition-fast: 0.2s ease;
    --transition-medium: 0.3s ease;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

a {
    color: var(--brand-accent);
    text-decoration: none;
    transition: color var(--transition-fast);
}
a:hover {
    color: var(--brand-hover);
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Typography */
h1, h2, h3 {
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.02em;
}

/* Button Styles */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    font-weight: 600;
    font-size: 15px;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    border: 1px solid transparent;
}

.btn-primary {
    background-color: var(--brand-primary);
    color: #fff;
    box-shadow: var(--shadow-sm);
}

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

.btn-outline {
    background-color: transparent;
    color: var(--brand-primary);
    border-color: var(--border-color);
}

.btn-outline:hover {
    background-color: rgba(29, 53, 87, 0.05);
    border-color: var(--brand-primary);
}

.btn-text {
    background: none;
    color: var(--text-secondary);
    padding: 12px;
}
.btn-text:hover {
    color: var(--brand-primary);
}

.btn-block {
    width: 100%;
}

/* Header */
.header {
    background-color: rgba(248, 249, 250, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    position: sticky;
    top: 0;
    z-index: 50;
    border-bottom: 1px solid var(--border-color);
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 72px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 700;
    font-size: 18px;
    color: var(--brand-primary);
}

.logo-icon {
    color: var(--brand-accent);
}

/* Hero Section */
.hero {
    padding: 80px 0 100px;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -10%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(69,123,157,0.1) 0%, rgba(248,249,250,0) 70%);
    z-index: -1;
}

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

.hero-title {
    font-size: 48px;
    margin-bottom: 24px;
    color: var(--brand-primary);
}

.hero-subtitle {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 36px;
    max-width: 480px;
}

.hero-actions {
    display: flex;
    gap: 16px;
    align-items: center;
}

/* Visual Mockup in Hero */
.bot-mockup {
    background: #ffffff;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
    overflow: hidden;
    transform: rotateY(-5deg) rotateX(5deg);
    transition: transform var(--transition-medium);
}
.bot-mockup:hover {
    transform: rotateY(0) rotateX(0);
}

.bot-header {
    background: var(--brand-primary);
    color: white;
    padding: 16px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.bot-avatar {
    width: 40px;
    height: 40px;
    background: rgba(255,255,255,0.2);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 14px;
}

.bot-info {
    display: flex;
    flex-direction: column;
}

.bot-info strong {
    font-size: 15px;
}

.bot-info span {
    font-size: 12px;
    opacity: 0.8;
}

.bot-body {
    padding: 24px;
    background: #f4f5f7;
    min-height: 280px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    background-image: url('data:image/svg+xml;utf8,<svg width="20" height="20" xmlns="http://www.w3.org/2000/svg"><circle cx="2" cy="2" r="1" fill="%23cbd5e1"/></svg>');
}

.message {
    max-width: 80%;
    padding: 12px 16px;
    border-radius: 16px;
    font-size: 14px;
    line-height: 1.4;
    animation: fadeIn 0.5s ease backwards;
}

.message.received {
    background: #ffffff;
    align-self: flex-start;
    border-bottom-left-radius: 4px;
    box-shadow: 0 1px 2px rgba(0,0,0,0.05);
}

.message.sent {
    background: var(--brand-accent);
    color: white;
    align-self: flex-end;
    border-bottom-right-radius: 4px;
    animation-delay: 0.3s;
}

.message:nth-child(3) {
    animation-delay: 0.6s;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Features Section */
.features {
    padding: 100px 0;
    background-color: var(--bg-color-alt);
}

.section-title {
    font-size: 36px;
    text-align: center;
    margin-bottom: 16px;
    color: var(--brand-primary);
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 60px;
    font-size: 18px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.feature-card {
    background: #ffffff;
    border-radius: var(--border-radius-md);
    padding: 32px;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-medium);
    border: 1px solid var(--border-color);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    border-color: rgba(69,123,157,0.3);
}

.feature-icon {
    width: 56px;
    height: 56px;
    background: rgba(69,123,157,0.1);
    color: var(--brand-accent);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
    transition: transform var(--transition-fast);
}

.feature-card:hover .feature-icon {
    transform: scale(1.05);
    background: var(--brand-accent);
    color: #fff;
}

.feature-title {
    font-size: 20px;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.feature-text {
    color: var(--text-secondary);
    font-size: 15px;
}

/* Footer */
.footer {
    padding: 40px 0;
    background-color: var(--brand-primary);
    color: rgba(255,255,255,0.7);
}

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

.footer-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
    color: #fff;
}

.footer-copy {
    font-size: 14px;
}

/* Auth Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(29, 53, 87, 0.4);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-medium);
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background: #ffffff;
    width: 100%;
    max-width: 440px;
    border-radius: var(--border-radius-lg);
    padding: 40px;
    position: relative;
    transform: scale(0.95);
    transition: transform var(--transition-medium);
    box-shadow: var(--shadow-lg);
}

.modal-overlay.active .modal-content {
    transform: scale(1);
}

.modal-close {
    position: absolute;
    top: 20px;
    right: 20px;
    background: none;
    border: none;
    font-size: 28px;
    color: var(--text-secondary);
    cursor: pointer;
    line-height: 1;
    transition: color var(--transition-fast);
}
.modal-close:hover {
    color: var(--text-primary);
}

.modal-header {
    text-align: center;
    margin-bottom: 32px;
}

.modal-header h2 {
    font-size: 24px;
    color: var(--brand-primary);
    margin-bottom: 8px;
}
.modal-header p {
    color: var(--text-secondary);
    font-size: 14px;
}

.auth-options {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.auth-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    width: 100%;
    padding: 14px;
    border-radius: var(--border-radius-sm);
    font-weight: 500;
    font-size: 15px;
    cursor: pointer;
    border: 1px solid var(--border-color);
    background: #fff;
    color: var(--text-primary);
    transition: all var(--transition-fast);
}
.auth-btn:hover {
    background: rgba(248, 249, 250, 1);
    border-color: rgba(43, 45, 66, 0.2);
}

.auth-vk {
    color: #0077FF;
}
.auth-yandex {
    color: #E60000;
}
.auth-telegram {
    color: #2AABEE;
}

.auth-divider {
    text-align: center;
    margin: 16px 0;
    position: relative;
    z-index: 1;
}
.auth-divider::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 0;
    right: 0;
    height: 1px;
    background: var(--border-color);
    z-index: -1;
}
.auth-divider span {
    background: #fff;
    padding: 0 12px;
    color: var(--text-secondary);
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.auth-phone-form {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.form-input {
    width: 100%;
    padding: 14px 16px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    font-size: 15px;
    font-family: inherit;
    transition: border-color var(--transition-fast);
}
.form-input:focus {
    outline: none;
    border-color: var(--brand-accent);
}

.modal-footer {
    text-align: center;
    margin-top: 24px;
    font-size: 12px;
    color: var(--text-secondary);
}

/* Responsive Design */
@media (max-width: 992px) {
    .hero-container {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    .bot-mockup {
        max-width: 500px;
        margin: 0 auto;
        transform: none;
    }
}

@media (max-width: 768px) {
    .hero-title {
        font-size: 36px;
    }
    .hero-actions {
        flex-direction: column;
        align-items: flex-start;
    }
    .btn-block {
        width: 100%;
    }
    .footer-container {
        flex-direction: column;
        gap: 16px;
    }
}