/* ============================================
   4sell.ai — Base: Variables, Reset, Layout
   ============================================ */

/* === CSS Variables === */
:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-card: rgba(18, 18, 30, 0.6);
    --bg-card-hover: rgba(28, 28, 45, 0.8);

    --text-primary: #f0f0f5;
    --text-secondary: #8888a0;
    --text-muted: #55556a;

    --accent-light: #57F357;
    --accent-dark: #14AA14;
    --accent-glow: rgba(87, 243, 87, 0.4);
    --accent-subtle: rgba(87, 243, 87, 0.08);
    --accent-border: rgba(87, 243, 87, 0.2);

    --gradient-main: linear-gradient(135deg, #57F357 0%, #14AA14 100%);
    --gradient-main-hover: linear-gradient(135deg, #6fff6f 0%, #1cc41c 100%);

    --glass-bg: rgba(255, 255, 255, 0.03);
    --glass-border: rgba(255, 255, 255, 0.08);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);

    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;

    --nav-height: 72px;
    --container-width: 1200px;

    --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
    --transition-fast: 0.2s var(--ease-out-expo);
    --transition-medium: 0.4s var(--ease-out-expo);
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    overflow-x: hidden;
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

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

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

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

.main-content {
    flex: 1;
    position: relative;
    z-index: 2;
    margin-top: var(--nav-height);
}

/* ── Screen sections: каждый экран = 1 viewport ── */
.screen-section {
    min-height: 100svh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: stretch;
    position: relative;
    box-sizing: border-box;
    overflow: hidden;
}

/* Screen1 учитывает nav */
.screen-section[data-screen="screen1"] {
    padding-top: var(--nav-height, 72px);
}

/* На мобилках — auto height для длинного контента */
@media (max-width: 768px) {
    .screen-section {
        min-height: 100svh;
        height: auto;
    }
}

/* ============================================
   Единые заголовки секций
   ============================================ */
.section-title {
    font-size: 3rem;
    font-weight: 900;
    color: #fff;
    line-height: 1.1;
    letter-spacing: -0.02em;
}

.section-subtitle {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-top: 8px;
}

@media (max-width: 768px) {
    .section-title {
        font-size: 2rem;
    }
    .section-subtitle {
        font-size: 0.85rem;
    }
}

@media (max-width: 560px) {
    .section-title {
        font-size: 1.5rem;
    }
}

/* ============================================
   Утилиты
   ============================================ */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0,0,0,0);
}

.desktop-only {
    display: block;
}

.mobile-only {
    display: none;
}

@media (max-width: 768px) {
    .desktop-only {
        display: none;
    }
    .mobile-only {
        display: block;
    }
}