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

:root {
    --accent: #2a7d6e;
    --accent-hover: #236b5e;
    --accent-light: #e8f5f1;
    --text: #1a1a1a;
    --text-light: #555;
    --text-on-dark: #e8e8e8;
    --bg: #fff;
    --bg-alt: #f7f8fa;
    --bg-dark: #0f1f1d;
    --bg-dark-card: #162b28;
    --border: #e5e7eb;
    --border-dark: #1e3d38;
    --radius: 8px;
    --max-width: 1080px;
}

html {
    scroll-behavior: smooth;
}

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

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

/* Nav */

.nav {
    position: sticky;
    top: 0;
    background: rgba(15, 31, 29, 0.95);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border-dark);
    z-index: 100;
}

.nav-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 60px;
}

.logo {
    font-weight: 700;
    font-size: 1.125rem;
    color: #fff;
    text-decoration: none;
}

.lang-toggle {
    background: none;
    border: 1px solid var(--border-dark);
    border-radius: var(--radius);
    padding: 6px 12px;
    font-family: inherit;
    font-size: 0.85rem;
    color: #6b8a85;
    display: flex;
    gap: 6px;
    align-items: center;
}

.lang-option {
    transition: color 0.2s;
    background: none;
    border: none;
    font-family: inherit;
    font-size: inherit;
    cursor: pointer;
    color: inherit;
    padding: 0;
}

.lang-option.active {
    color: #fff;
    font-weight: 600;
}

.lang-divider {
    color: var(--border-dark);
}

/* Hero */

.hero {
    padding: 120px 0 100px;
    text-align: center;
    background: linear-gradient(160deg, var(--bg-dark) 0%, #0a2a24 50%, #163832 100%);
    color: #fff;
}

.hero h1 {
    font-size: clamp(2rem, 5vw, 3.25rem);
    font-weight: 700;
    line-height: 1.15;
    max-width: 720px;
    margin: 0 auto 24px;
    letter-spacing: -0.02em;
}

.hero-sub {
    font-size: clamp(1.05rem, 2.5vw, 1.25rem);
    color: var(--text-on-dark);
    max-width: 600px;
    margin: 0 auto 40px;
    line-height: 1.6;
}

/* Buttons */

.btn {
    display: inline-block;
    background: var(--accent);
    color: #fff;
    padding: 14px 32px;
    border-radius: var(--radius);
    font-family: inherit;
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    border: none;
    cursor: pointer;
    transition: background 0.2s;
}

.btn:hover {
    background: var(--accent-hover);
}

.hero .btn {
    background: #fff;
    color: var(--bg-dark);
}

.hero .btn:hover {
    background: var(--accent-light);
}

/* Problem */

.problem {
    padding: 100px 0;
    background: var(--bg-alt);
}

.problem h2,
.steps h2,
.audience h2,
.signup h2 {
    text-align: center;
    font-size: clamp(1.5rem, 3.5vw, 2.25rem);
    font-weight: 700;
    margin-bottom: 56px;
    letter-spacing: -0.01em;
}

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

.problem-card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 32px;
    transition: box-shadow 0.2s;
}

.problem-card:hover {
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
}

.problem-icon {
    color: var(--accent);
    margin-bottom: 16px;
}

.problem-card h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.problem-card p {
    color: var(--text-light);
    font-size: 0.95rem;
}

/* Steps */

.steps {
    padding: 100px 0;
}

.steps-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 32px;
    position: relative;
}

.step {
    text-align: center;
}

.step-number {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--accent);
    color: #fff;
    font-weight: 700;
    font-size: 1.25rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    box-shadow: 0 4px 12px rgba(42, 125, 110, 0.3);
}

.step h3 {
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.step p {
    color: var(--text-light);
    font-size: 0.95rem;
}

/* Audience */

.audience {
    padding: 100px 0;
    background: var(--bg-alt);
}

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

.audience-card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 32px 24px;
    text-align: center;
    transition: box-shadow 0.2s;
}

.audience-card:hover {
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
}

.audience-icon {
    color: var(--accent);
    margin-bottom: 12px;
}

.audience-card h3 {
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.audience-card p {
    color: var(--text-light);
    font-size: 0.95rem;
}

/* Signup */

.signup {
    padding: 100px 0;
    text-align: center;
    background: var(--bg-dark);
    color: #fff;
}

.signup-sub {
    color: var(--text-on-dark);
    font-size: 1.1rem;
    margin-top: -40px;
    margin-bottom: 40px;
}

.signup-form {
    display: flex;
    gap: 12px;
    justify-content: center;
    max-width: 480px;
    margin: 0 auto 16px;
}

.signup-form input {
    flex: 1;
    padding: 14px 16px;
    border: 1px solid var(--border-dark);
    border-radius: var(--radius);
    font-family: inherit;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s;
    background: var(--bg-dark-card);
    color: #fff;
}

.signup-form input::placeholder {
    color: #6b8a85;
}

.signup-form input:focus {
    border-color: var(--accent);
}

.signup-form .btn {
    white-space: nowrap;
}

.signup-privacy {
    color: #6b8a85;
    font-size: 0.85rem;
}

.signup-success {
    color: var(--accent);
    font-weight: 500;
    font-size: 1.1rem;
    display: none;
}

/* Footer */

.footer {
    padding: 32px 0;
    border-top: 1px solid var(--border-dark);
    text-align: center;
    color: #6b8a85;
    font-size: 0.85rem;
    background: var(--bg-dark);
}

/* Responsive */

@media (max-width: 768px) {
    .hero {
        padding: 80px 0 60px;
    }

    .problem,
    .steps,
    .audience,
    .signup {
        padding: 64px 0;
    }

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

    .steps-grid {
        grid-template-columns: 1fr 1fr;
        gap: 40px 24px;
    }

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

    .signup-form {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .steps-grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }

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