html,
body {
    height: 100%;
    width: 100%;
}

* {
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}

body {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    font-family: "Roboto", "SF Pro SC", "SF Pro Display", "SF Pro Icons", "PingFang SC", BlinkMacSystemFont, -apple-system, "Segoe UI", "Microsoft Yahei", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", "Helvetica", "Arial", sans-serif;
    font-weight: 400;
    margin: 0;
    color: #2d3748;
    background: #fff;
}

a {
    -webkit-transition: all 0.25s;
    -moz-transition: all 0.25s;
    transition: all 0.25s;
    color: #25d366;
    text-decoration: none;
}

a:hover,
a:focus {
    color: #1da851;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    letter-spacing: -0.02em;
    margin: 0 0 16px;
    color: #171347;
}

p {
    font-size: 16px;
    line-height: 1.7;
    margin: 0 0 16px;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Header */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid #edf2f7;
}

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

.logo {
    font-size: 16px;
    font-weight: 700;
    color: #171347 !important;
}

.nav-links {
    display: flex;
    gap: 24px;
}

.nav-links a {
    font-size: 14px;
    color: #4a5568 !important;
    font-weight: 500;
}

.nav-links a:hover {
    color: #25d366 !important;
}

/* Buttons */
.btn-primary {
    display: inline-block;
    background: linear-gradient(135deg, #25d366, #128c7e);
    color: #fff !important;
    font-weight: 600;
    font-size: 15px;
    padding: 14px 32px;
    border-radius: 50px;
    letter-spacing: 0.02em;
    box-shadow: 0 4px 14px rgba(37, 211, 102, 0.35);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(37, 211, 102, 0.45);
    color: #fff !important;
}

.btn-secondary {
    display: inline-block;
    color: #171347 !important;
    font-weight: 600;
    font-size: 15px;
    padding: 14px 32px;
    border-radius: 50px;
    border: 2px solid #e2e8f0;
    background: #fff;
}

.btn-secondary:hover {
    border-color: #25d366;
    color: #25d366 !important;
}

/* Hero */
.hero {
    background: linear-gradient(160deg, #f0fdf4 0%, #f1f6fd 50%, #fff 100%);
    padding: 80px 0 100px;
    overflow: hidden;
}

.hero-inner {
    display: flex;
    align-items: center;
    gap: 60px;
}

.hero-text {
    flex: 1;
}

.badge {
    display: inline-block;
    background: #dcfce7;
    color: #15803d;
    font-size: 13px;
    font-weight: 600;
    padding: 6px 14px;
    border-radius: 50px;
    margin-bottom: 20px;
}

.hero h1 {
    font-size: 46px;
    line-height: 1.15;
    margin-bottom: 20px;
}

.hero-desc {
    font-size: 18px;
    color: #4a5568;
    max-width: 520px;
    margin-bottom: 32px;
}

.hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
    margin-bottom: 16px;
}

.hero-note {
    font-size: 13px;
    color: #718096;
}

.hero-visual {
    flex: 0 0 280px;
}

.phone-mock {
    background: #171347;
    border-radius: 36px;
    padding: 12px;
    box-shadow: 0 20px 60px rgba(23, 19, 71, 0.25);
}

.phone-screen {
    background: #e5ddd5;
    border-radius: 26px;
    padding: 24px 16px;
    min-height: 360px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.msg {
    background: #fff;
    border-radius: 8px 8px 8px 2px;
    padding: 10px 14px;
    max-width: 85%;
    box-shadow: 0 1px 2px rgba(0,0,0,0.08);
}

.msg p {
    font-size: 14px;
    margin: 0;
    color: #2d3748;
}

.msg-deleted {
    background: #fef3c7;
    border-left: 3px solid #f59e0b;
}

.msg-label {
    display: block;
    font-size: 11px;
    font-weight: 600;
    color: #b45309;
    margin-bottom: 4px;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

/* Sections */
.section {
    padding: 80px 0;
}

.section-title {
    text-align: center;
    font-size: 32px;
    margin-bottom: 48px;
}

/* Features */
.features {
    background: #fff;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.feature-card {
    background: #f8fafc;
    border-radius: 16px;
    padding: 32px 24px;
    text-align: center;
    border: 1px solid #edf2f7;
    transition: transform 0.25s, box-shadow 0.25s;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.06);
}

.feature-icon {
    font-size: 36px;
    margin-bottom: 16px;
}

.feature-card h3 {
    font-size: 18px;
    margin-bottom: 10px;
}

.feature-card p {
    font-size: 14px;
    color: #718096;
    margin: 0;
}

/* How it works */
.how-it-works {
    background: #f8fafc;
}

.steps {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
    margin-bottom: 40px;
}

.step {
    text-align: center;
    padding: 24px;
}

.step-num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, #25d366, #128c7e);
    color: #fff;
    font-size: 20px;
    font-weight: 700;
    border-radius: 50%;
    margin-bottom: 16px;
}

.step h3 {
    font-size: 18px;
}

.step p {
    font-size: 14px;
    color: #718096;
    margin: 0;
}

.notice {
    background: #fff;
    border-left: 4px solid #f59e0b;
    border-radius: 8px;
    padding: 20px 24px;
    font-size: 14px;
    color: #4a5568;
    line-height: 1.7;
    max-width: 800px;
    margin: 0 auto;
}

/* CTA */
.cta {
    background: linear-gradient(135deg, #171347, #2d3748);
    color: #fff;
    text-align: center;
}

.cta h2 {
    color: #fff;
    font-size: 32px;
}

.cta p {
    color: rgba(255,255,255,0.75);
    font-size: 18px;
    margin-bottom: 32px;
}

.cta .btn-primary {
    background: linear-gradient(135deg, #25d366, #1da851);
}

/* Footer */
.footer {
    background-color: #171347;
    padding: 32px 0;
    color: rgba(255, 255, 255, 0.6);
    text-align: center;
}

.footer p {
    font-size: 14px;
    margin: 0 0 8px;
}

.footer a {
    color: rgba(255, 255, 255, 0.85);
}

.footer a:hover {
    color: #25d366;
}

.footer-disclaimer {
    font-size: 12px !important;
    color: rgba(255, 255, 255, 0.4) !important;
    margin-top: 12px !important;
}

/* Responsive */
@media (max-width: 992px) {
    .feature-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .site-header .container {
        flex-direction: column;
        height: auto;
        padding: 16px 24px;
        gap: 12px;
    }

    .nav-links {
        gap: 16px;
        flex-wrap: wrap;
        justify-content: center;
    }

    .hero {
        padding: 48px 0 64px;
    }

    .hero-inner {
        flex-direction: column;
        gap: 40px;
        text-align: center;
    }

    .hero h1 {
        font-size: 32px;
    }

    .hero-desc {
        margin-left: auto;
        margin-right: auto;
    }

    .hero-actions {
        justify-content: center;
    }

    .hero-visual {
        flex: none;
        width: 240px;
    }

    .steps {
        grid-template-columns: 1fr;
        gap: 16px;
    }

    .feature-grid {
        grid-template-columns: 1fr;
    }

    .section {
        padding: 56px 0;
    }

    .section-title {
        font-size: 26px;
    }
}