:root {
    --primary-color: #10a37f;
    --primary-hover: #0d8c6d;
    --primary-soft: rgba(16, 163, 127, 0.12);
    --bg-color: #ffffff;
    --bg-alt: #f7f7f8;
    --text-primary: #202123;
    --text-secondary: #565869;
    --border-color: #e5e5e5;
    --card-bg: #ffffff;
    --shadow-light: rgba(0, 0, 0, 0.06);
    --shadow-medium: rgba(0, 0, 0, 0.12);
    --hero-grad-1: #0d8c6d;
    --hero-grad-2: #10a37f;
    --nav-bg: rgba(255, 255, 255, 0.85);
    --bubble-user: #0d8c6d;
    --bubble-assistant: #ececf1;
    --bubble-text: #202123;
}

body.dark-theme {
    --primary-color: #10a37f;
    --primary-hover: #0d8c6d;
    --primary-soft: rgba(16, 163, 127, 0.18);
    --bg-color: #141416;
    --bg-alt: #1a1a1d;
    --text-primary: #ffffff;
    --text-secondary: #b0b0b0;
    --border-color: #303033;
    --card-bg: #1f1f22;
    --shadow-light: rgba(0, 0, 0, 0.3);
    --shadow-medium: rgba(0, 0, 0, 0.5);
    --hero-grad-1: #0a5c47;
    --hero-grad-2: #0d8c6d;
    --nav-bg: rgba(20, 20, 22, 0.85);
    --bubble-user: #0d8c6d;
    --bubble-assistant: #2d2d30;
    --bubble-text: #ffffff;
}

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

html { scroll-behavior: smooth; }

body {
    font-family: 'Inter', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 22px;
    border-radius: 10px;
    font-size: 0.95rem;
    font-weight: 600;
    font-family: 'Inter', sans-serif;
    border: 1px solid transparent;
    cursor: pointer;
    transition: all 0.2s;
    white-space: nowrap;
}

.btn-lg { padding: 14px 28px; font-size: 1rem; border-radius: 12px; }

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

.btn-primary:hover { background-color: var(--primary-hover); transform: translateY(-1px); box-shadow: 0 8px 20px var(--primary-soft); }

.btn-ghost {
    background-color: transparent;
    color: var(--text-primary);
    border-color: var(--border-color);
}

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

.btn-light {
    background-color: #ffffff;
    color: #0d8c6d;
}

.btn-light:hover { background-color: #f0f0f0; }

/* ===== NAVBAR ===== */

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background-color: var(--nav-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
}

.navbar-inner {
    max-width: 1100px;
    margin: 0 auto;
    padding: 14px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.25rem;
    font-weight: 700;
}

.brand-icon {
    width: 38px;
    height: 38px;
    border-radius: 10px;
    background: linear-gradient(135deg, var(--hero-grad-1), var(--hero-grad-2));
    color: #ffffff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
}

.nav-links { display: flex; align-items: center; gap: 28px; }

.nav-link {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    transition: color 0.2s;
}

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

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

.theme-toggle {
    width: 40px;
    height: 40px;
    border-radius: 10px;
    background-color: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    transition: all 0.2s;
}

.theme-toggle:hover { border-color: var(--primary-color); color: var(--primary-color); }

.nav-burger {
    display: none;
    width: 40px;
    height: 40px;
    border-radius: 10px;
    background-color: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    cursor: pointer;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
}

/* ===== HERO ===== */

.hero {
    padding: 160px 24px 90px;
    background:
        radial-gradient(700px 300px at 85% -10%, var(--primary-soft), transparent 60%),
        linear-gradient(180deg, var(--bg-alt), var(--bg-color));
}

.hero-inner {
    max-width: 1100px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1.05fr 0.95fr;
    gap: 56px;
    align-items: center;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background-color: var(--primary-soft);
    color: var(--primary-color);
    font-size: 0.8rem;
    font-weight: 600;
    padding: 8px 14px;
    border-radius: 30px;
    margin-bottom: 22px;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: -0.5px;
    margin-bottom: 20px;
}

.hero h1 .accent { color: var(--primary-color); }

.hero-sub {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 520px;
    margin-bottom: 30px;
}

.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 26px; }

.hero-meta {
    display: flex;
    gap: 22px;
    flex-wrap: wrap;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.hero-meta i { color: var(--primary-color); margin-right: 6px; }

.hero-visual { display: flex; justify-content: center; }

.chat-preview {
    width: 100%;
    max-width: 420px;
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 22px;
    box-shadow: 0 20px 50px var(--shadow-medium);
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.preview-msg { display: flex; gap: 10px; align-items: flex-start; }

.preview-msg.preview-user { flex-direction: row-reverse; }

.preview-avatar {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    background-color: var(--primary-color);
    color: #ffffff;
    font-size: 0.8rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.preview-avatar.lucy { background: linear-gradient(135deg, var(--hero-grad-1), var(--hero-grad-2)); }

.preview-bubble {
    padding: 10px 14px;
    border-radius: 14px;
    font-size: 0.88rem;
    color: var(--bubble-text);
    max-width: 78%;
    animation: fadeUp 0.5s ease both;
}

.preview-msg.preview-user .preview-bubble { background-color: var(--bubble-user); color: #ffffff; }

.preview-msg.preview-lucy .preview-bubble { background-color: var(--bubble-assistant); }

.preview-msg:nth-child(2) .preview-bubble { animation-delay: 0.4s; }
.preview-msg:nth-child(3) .preview-bubble { animation-delay: 0.8s; }

@keyframes fadeUp {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ===== SECTIONS ===== */

.section { padding: 90px 24px; }

.section-alt { background-color: var(--bg-alt); }

.section-inner { max-width: 1100px; margin: 0 auto; }

.section-head { text-align: center; max-width: 680px; margin: 0 auto 56px; }

.section-tag {
    display: inline-block;
    background-color: var(--primary-soft);
    color: var(--primary-color);
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    padding: 6px 14px;
    border-radius: 30px;
    margin-bottom: 16px;
}

.section-head h2 { font-size: 2.2rem; font-weight: 800; letter-spacing: -0.4px; margin-bottom: 14px; }

.section-sub { color: var(--text-secondary); font-size: 1.05rem; }

/* ===== FEATURES ===== */

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 22px;
}

.feature-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 28px;
    transition: all 0.25s;
    opacity: 0;
    transform: translateY(20px);
}

.feature-card.visible { opacity: 1; transform: translateY(0); transition: opacity 0.5s ease, transform 0.5s ease, box-shadow 0.25s, border-color 0.25s; }

.feature-card:hover { border-color: var(--primary-color); box-shadow: 0 12px 30px var(--shadow-medium); transform: translateY(-4px); }

.feature-icon {
    width: 48px;
    height: 48px;
    border-radius: 12px;
    background: linear-gradient(135deg, var(--hero-grad-1), var(--hero-grad-2));
    color: #ffffff;
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 18px;
}

.feature-card h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 8px; }

.feature-card p { font-size: 0.9rem; color: var(--text-secondary); }

/* ===== APPROACH ===== */

.approach-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 26px;
}

.approach-item {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 30px;
    position: relative;
    opacity: 0;
    transform: translateY(20px);
}

.approach-item.visible { opacity: 1; transform: translateY(0); transition: opacity 0.5s ease, transform 0.5s ease; }

.approach-num {
    font-size: 0.85rem;
    font-weight: 800;
    color: var(--primary-color);
    letter-spacing: 2px;
    margin-bottom: 14px;
}

.approach-item h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 10px; }

.approach-item p { font-size: 0.92rem; color: var(--text-secondary); }

/* ===== STEPS ===== */

.steps {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 22px;
    margin-bottom: 48px;
}

.step {
    text-align: center;
    padding: 28px 18px;
    opacity: 0;
    transform: translateY(20px);
}

.step.visible { opacity: 1; transform: translateY(0); transition: opacity 0.5s ease, transform 0.5s ease; }

.step-icon {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--hero-grad-1), var(--hero-grad-2));
    color: #ffffff;
    font-size: 1.4rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 18px;
    box-shadow: 0 8px 20px var(--primary-soft);
}

.step h3 { font-size: 1rem; font-weight: 700; margin-bottom: 8px; }

.step p { font-size: 0.88rem; color: var(--text-secondary); }

.platforms {
    display: flex;
    justify-content: center;
    gap: 14px;
    flex-wrap: wrap;
}

.platform-chip {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 30px;
    padding: 10px 18px;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.platform-chip i { color: var(--primary-color); }

/* ===== CTA ===== */

.cta {
    padding: 90px 24px;
    background: linear-gradient(135deg, var(--hero-grad-1), var(--hero-grad-2));
    text-align: center;
}

.cta-inner { max-width: 640px; margin: 0 auto; }

.cta h2 { color: #ffffff; font-size: 2.2rem; font-weight: 800; letter-spacing: -0.4px; margin-bottom: 14px; }

.cta p { color: rgba(255, 255, 255, 0.85); font-size: 1.05rem; margin-bottom: 30px; }

.cta-buttons { display: flex; justify-content: center; gap: 14px; flex-wrap: wrap; }

/* ===== FOOTER ===== */

.footer { background-color: var(--bg-alt); border-top: 1px solid var(--border-color); padding: 50px 24px; }

.footer-inner { max-width: 1100px; margin: 0 auto; text-align: center; }

.footer-brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 10px;
}

.footer-tag { font-size: 0.85rem; color: var(--text-secondary); margin-bottom: 20px; }

.footer-links { display: flex; justify-content: center; gap: 24px; margin-bottom: 20px; }

.footer-links a { font-size: 0.9rem; color: var(--text-secondary); transition: color 0.2s; }

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

.footer-legal { font-size: 0.8rem; color: var(--text-secondary); opacity: 0.8; }

/* ===== RESPONSIVE ===== */

@media (max-width: 900px) {
    .hero-inner { grid-template-columns: 1fr; gap: 40px; }
    .hero { padding-top: 140px; }
    .hero-visual { order: 2; }
    .features-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 640px) {
    .nav-links {
        position: fixed;
        top: 68px;
        left: 0;
        right: 0;
        background-color: var(--nav-bg);
        backdrop-filter: blur(12px);
        -webkit-backdrop-filter: blur(12px);
        border-bottom: 1px solid var(--border-color);
        flex-direction: column;
        align-items: flex-start;
        padding: 16px 24px;
        gap: 16px;
        display: none;
    }
    .nav-links.open { display: flex; }
    .nav-burger { display: flex; }
    .nav-actions .btn-ghost { display: none; }

    .hero h1 { font-size: 2.1rem; }
    .hero-sub { font-size: 1rem; }
    .hero-cta { flex-direction: column; }
    .hero-cta .btn { width: 100%; }

    .features-grid { grid-template-columns: 1fr; }
    .approach-grid { grid-template-columns: 1fr; }
    .steps { grid-template-columns: 1fr 1fr; }
    .section { padding: 64px 20px; }
    .section-head h2 { font-size: 1.7rem; }
    .cta h2 { font-size: 1.7rem; }
}

@media (max-width: 380px) {
    .steps { grid-template-columns: 1fr; }
}