/* ========================================
   Potato Chat - Official Website Style
   White Theme | Blue Accent | Rocket Logo
   ======================================== */

:root {
    --primary: #2196F3;
    --primary-dark: #1976D2;
    --primary-light: #64B5F6;
    --primary-hover: #1E88E5;
    --accent: #FF9800;
    --accent-dark: #F57C00;
    --bg-white: #FFFFFF;
    --bg-light: #F8FAFC;
    --bg-gray: #F1F5F9;
    --text-dark: #1E293B;
    --text-medium: #475569;
    --text-light: #64748B;
    --text-muted: #94A3B8;
    --border: #E2E8F0;
    --border-light: #F1F5F9;
    --gradient-primary: linear-gradient(135deg, #2196F3 0%, #1976D2 100%);
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
    --shadow: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.06);
    --shadow-lg: 0 8px 30px rgba(0,0,0,0.08);
    --radius-sm: 6px;
    --radius: 10px;
    --radius-md: 14px;
    --radius-lg: 20px;
    --radius-xl: 28px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    color: var(--text-dark);
    line-height: 1.6;
    background: var(--bg-white);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: inherit; transition: var(--transition); }
img { max-width: 100%; height: auto; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* ========================================
   Header & Navigation
   ======================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255,255,255,0.98);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: var(--transition);
}
.header.scrolled { box-shadow: var(--shadow-md); }

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

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-dark);
}
.logo-icon { width: 44px; height: 44px; display: flex; align-items: center; justify-content: center; flex-shrink: 0; }
.logo-icon svg { width: 100%; height: 100%; }
.logo-text { display: flex; flex-direction: column; line-height: 1.2; }
.logo-text span:first-child { font-size: 1.3rem; font-weight: 800; letter-spacing: -0.5px; }
.logo-text span:last-child { font-size: 0.7rem; font-weight: 500; color: var(--text-light); text-transform: uppercase; letter-spacing: 1px; }

.nav-menu { display: flex; list-style: none; gap: 8px; }
.nav-menu a {
    display: block;
    padding: 10px 18px;
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--text-medium);
    border-radius: var(--radius);
    transition: var(--transition);
}
.nav-menu a:hover { color: var(--primary); background: rgba(33,150,243,0.06); }
.nav-menu a.active { color: var(--primary); background: rgba(33,150,243,0.08); font-weight: 600; }

.nav-right { display: flex; align-items: center; gap: 20px; }

.lang-switch {
    display: flex;
    gap: 4px;
    background: var(--bg-gray);
    padding: 4px;
    border-radius: var(--radius);
}
.lang-btn {
    padding: 8px 16px;
    border: none;
    background: transparent;
    cursor: pointer;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    font-weight: 600;
    transition: var(--transition);
    color: var(--text-light);
}
.lang-btn.active { background: var(--primary); color: white; box-shadow: 0 2px 8px rgba(33,150,243,0.3); }

.mobile-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 8px; border-radius: var(--radius-sm); }
.mobile-toggle:hover { background: var(--bg-gray); }
.mobile-toggle span { width: 22px; height: 2px; background: var(--text-dark); border-radius: 2px; transition: var(--transition); }

/* ========================================
   Hero Section
   ======================================== */
.hero {
    padding: 140px 0 80px;
    background: linear-gradient(180deg, #FFFFFF 0%, #F8FAFC 100%);
    position: relative;
    overflow: hidden;
}
.hero::before {
    content: '';
    position: absolute;
    top: 0; right: 0;
    width: 50%; height: 100%;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%232196F3' fill-opacity='0.03'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.hero-content { display: grid; grid-template-columns: 1fr 1fr; gap: 60px; align-items: center; position: relative; z-index: 1; }
.hero-text h1 { font-size: 3.2rem; font-weight: 800; line-height: 1.15; margin-bottom: 24px; color: var(--text-dark); letter-spacing: -1px; }
.hero-text h1 .highlight { background: var(--gradient-primary); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.hero-text p { font-size: 1.15rem; color: var(--text-light); margin-bottom: 36px; line-height: 1.8; max-width: 520px; }
.hero-btns { display: flex; gap: 16px; flex-wrap: wrap; }

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 16px 32px;
    border-radius: var(--radius);
    font-weight: 600;
    font-size: 1rem;
    transition: var(--transition);
    cursor: pointer;
    border: none;
}
.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 4px 14px rgba(33,150,243,0.3);
}
.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(33,150,243,0.35);
}
.btn-secondary {
    background: white;
    color: var(--primary);
    border: 2px solid var(--primary);
}
.btn-secondary:hover { background: var(--primary); color: white; }

.hero-image { position: relative; display: flex; justify-content: center; }
.hero-mockup {
    width: 380px;
    height: 500px;
    background: #FFFFFF;
    border-radius: var(--radius-xl);
    box-shadow: 0 25px 80px rgba(33,150,243,0.15), 0 10px 30px rgba(0,0,0,0.06);
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: hidden;
    border: 1px solid var(--border);
}

.mockup-chat {
    display: flex;
    flex-direction: column;
    height: 100%;
}

.mockup-header {
    padding: 16px 20px;
    background: linear-gradient(135deg, #2196F3 0%, #1976D2 100%);
    display: flex;
    align-items: center;
    gap: 6px;
    flex-shrink: 0;
}

.mockup-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: rgba(255,255,255,0.3);
}

.mockup-dot:first-child { background: #FF6B6B; }
.mockup-dot:nth-child(2) { background: #FFD93D; }
.mockup-dot:nth-child(3) { background: #6BCB77; }

.mockup-title {
    color: white;
    font-size: 0.85rem;
    font-weight: 600;
    margin-left: 8px;
    opacity: 0.9;
}

.mockup-body {
    flex: 1;
    padding: 16px;
    background: #F8FAFC;
    display: flex;
    flex-direction: column;
    gap: 12px;
    overflow: hidden;
}

.chat-bubble {
    display: flex;
    align-items: flex-start;
    gap: 8px;
    max-width: 85%;
    animation: bubbleIn 0.4s ease forwards;
    opacity: 0;
}

.chat-bubble:nth-child(1) { animation-delay: 0.1s; }
.chat-bubble:nth-child(2) { animation-delay: 0.3s; }
.chat-bubble:nth-child(3) { animation-delay: 0.5s; }
.chat-bubble:nth-child(4) { animation-delay: 0.7s; }

.chat-bubble.incoming {
    align-self: flex-start;
}

.chat-bubble.outgoing {
    align-self: flex-end;
    flex-direction: row-reverse;
}

.bubble-avatar {
    width: 28px;
    height: 28px;
    background: #E3F2FD;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    flex-shrink: 0;
}

.bubble-text {
    padding: 10px 14px;
    border-radius: 14px;
    font-size: 0.8rem;
    line-height: 1.4;
    word-break: break-all;
}

.chat-bubble.incoming .bubble-text {
    background: white;
    color: var(--text-dark);
    border: 1px solid var(--border);
    border-top-left-radius: 4px;
}

.chat-bubble.outgoing .bubble-text {
    background: linear-gradient(135deg, #2196F3 0%, #1976D2 100%);
    color: white;
    border-top-right-radius: 4px;
}

.mockup-input {
    padding: 10px 16px;
    background: white;
    border-top: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 8px;
    flex-shrink: 0;
}

.input-placeholder {
    flex: 1;
    color: var(--text-muted);
    font-size: 0.8rem;
}

.input-send {
    width: 28px;
    height: 28px;
    background: var(--primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
}

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

/* ========================================
   Stats Section
   ======================================== */
.stats { background: var(--bg-light); padding: 70px 0; border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 40px; text-align: center; }
.stat-item { padding: 20px; }
.stat-item h3 { font-size: 3rem; font-weight: 800; color: var(--primary); margin-bottom: 8px; letter-spacing: -1px; }
.stat-item p { font-size: 1rem; color: var(--text-light); font-weight: 500; }

/* ========================================
   Section Styles
   ======================================== */
.section { padding: 100px 0; }
.section-header { text-align: center; margin-bottom: 60px; }
.section-header h2 { font-size: 2.4rem; font-weight: 700; margin-bottom: 16px; color: var(--text-dark); letter-spacing: -0.5px; }
.section-header p { font-size: 1.1rem; color: var(--text-light); max-width: 600px; margin: 0 auto; }
.section-alt { background: var(--bg-light); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }

/* ========================================
   Features Grid
   ======================================== */
.features-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 28px; }
.feature-card {
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    padding: 36px;
    border: 1px solid var(--border);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}
.feature-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transition: var(--transition);
}
.feature-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); border-color: transparent; }
.feature-card:hover::before { transform: scaleX(1); }
.feature-icon {
    width: 64px; height: 64px;
    background: linear-gradient(135deg, rgba(33,150,243,0.1) 0%, rgba(33,150,243,0.05) 100%);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    font-size: 1.8rem;
}
.feature-card h3 { font-size: 1.2rem; font-weight: 700; margin-bottom: 12px; color: var(--text-dark); }
.feature-card p { color: var(--text-light); line-height: 1.7; font-size: 0.95rem; }

/* ========================================
   Download Grid
   ======================================== */
.download-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 24px; }
.download-card {
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    padding: 40px 30px;
    text-align: center;
    border: 1px solid var(--border);
    transition: var(--transition);
}
.download-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); border-color: var(--primary-light); }
.download-card .icon { font-size: 3.5rem; margin-bottom: 16px; display: block; }
.download-card h3 { font-size: 1.25rem; font-weight: 700; margin-bottom: 8px; color: var(--text-dark); }
.download-card p { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 24px; }
.download-card .btn { padding: 12px 28px; font-size: 0.95rem; }
.download-card .meta { margin-top:10px; font-size:0.8rem; color:var(--text-muted); }
.download-list { text-align:left; margin:15px 0; padding-left:20px; color:var(--text-light); font-size:0.9rem; list-style:disc; }
.download-list li { margin-bottom:6px; line-height:1.5; }
.download-web { max-width:600px; margin:0 auto; text-align:center; background:var(--bg-white); border-radius:var(--radius-lg); padding:50px; border:1px solid var(--border); transition:var(--transition); }
.download-web:hover { box-shadow:var(--shadow-md); transform:translateY(-2px); }
.download-web .icon { font-size:4rem; display:block; margin-bottom:20px; }
.download-web h3 { font-size:1.25rem; font-weight:700; margin-bottom:8px; color:var(--text-dark); }
.download-web p { color:var(--text-light); font-size:0.95rem; margin-bottom:20px; }
.download-web .btn { margin-top:20px; }

/* ========================================
   News Grid
   ======================================== */
.news-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(340px, 1fr)); gap: 28px; }
.news-card {
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--border);
    transition: var(--transition);
}
.news-card:hover { box-shadow: var(--shadow-lg); transform: translateY(-4px); }
.news-card .news-image { height: 200px; background: linear-gradient(135deg, #E3F2FD 0%, #BBDEFB 100%); display: flex; align-items: center; justify-content: center; font-size: 4rem; }
.news-card .news-content { padding: 28px; }
.news-card .news-date { color: var(--primary); font-size: 0.85rem; font-weight: 600; margin-bottom: 12px; }
.news-card h3 { font-size: 1.15rem; font-weight: 700; margin-bottom: 12px; line-height: 1.4; color: var(--text-dark); }
.news-card p { color: var(--text-light); font-size: 0.95rem; line-height: 1.6; }

/* ========================================
   FAQ Accordion
   ======================================== */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
    background: var(--bg-white);
    border-radius: var(--radius);
    margin-bottom: 12px;
    border: 1px solid var(--border);
    overflow: hidden;
    transition: var(--transition);
}
.faq-item:hover { border-color: var(--primary-light); }
.faq-item.active { border-color: var(--primary); box-shadow: var(--shadow-sm); }
.faq-question {
    padding: 22px 28px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    font-weight: 600;
    font-size: 1rem;
    color: var(--text-dark);
    transition: var(--transition);
}
.faq-question:hover { color: var(--primary); }
.faq-question::after { content: '+'; font-size: 1.5rem; font-weight: 300; color: var(--primary); transition: var(--transition); }
.faq-item.active .faq-question::after { transform: rotate(45deg); }
.faq-answer { padding: 0 28px; max-height: 0; overflow: hidden; transition: all 0.3s ease; color: var(--text-light); line-height: 1.8; font-size: 0.95rem; }
.faq-item.active .faq-answer { padding: 0 28px 24px; max-height: 500px; }

/* ========================================
   Page Header
   ======================================== */
.page-header {
    padding: 150px 0 70px;
    background: var(--gradient-primary);
    color: white;
    text-align: center;
    position: relative;
    overflow: hidden;
}
.page-header::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='100' height='100' viewBox='0 0 100 100' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M11 18c3.866 0 7-3.134 7-7s-3.134-7-7-7-7 3.134-7 7 3.134 7 7 7zm48 25c3.866 0 7-3.134 7-7s-3.134-7-7-7-7 3.134-7 7 3.134 7 7 7z' fill='%23ffffff' fill-opacity='0.05' fill-rule='evenodd'/%3E%3C/svg%3E");
}
.page-header h1 { font-size: 2.8rem; font-weight: 800; margin-bottom: 16px; position: relative; }
.page-header p { font-size: 1.15rem; opacity: 0.9; max-width: 600px; margin: 0 auto; position: relative; }

/* ========================================
   Footer
   ======================================== */
.footer { background: var(--bg-light); color: var(--text-dark); padding: 80px 0 40px; border-top: 1px solid var(--border); }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 50px; margin-bottom: 50px; }
.footer-brand .logo { margin-bottom: 20px; }
.footer-brand p { color: var(--text-light); line-height: 1.7; margin-bottom: 24px; font-size: 0.95rem; }
.footer-social { display: flex; gap: 12px; }
.footer-social a {
    width: 42px; height: 42px;
    background: var(--bg-white); border: 1px solid var(--border);
    border-radius: var(--radius);
    display: flex; align-items: center; justify-content: center;
    font-size: 1.2rem; transition: var(--transition); color: var(--text-medium);
}
.footer-social a:hover { background: var(--primary); color: white; border-color: var(--primary); transform: translateY(-3px); }
.footer-links h4 { font-size: 1rem; font-weight: 700; margin-bottom: 24px; color: var(--text-dark); }
.footer-links ul { list-style: none; }
.footer-links li { margin-bottom: 14px; }
.footer-links a { color: var(--text-light); font-size: 0.95rem; transition: var(--transition); }
.footer-links a:hover { color: var(--primary); padding-left: 4px; }
.footer-bottom { border-top: 1px solid var(--border); padding-top: 30px; text-align: center; color: var(--text-muted); font-size: 0.9rem; }

/* ========================================
   Language Switching
   ======================================== */
[data-lang] { display: none; }
[data-lang].active { display: block; }
span[data-lang], a[data-lang], button[data-lang], li[data-lang] { display: none; }
span[data-lang].active, a[data-lang].active, button[data-lang].active { display: inline; }
li[data-lang].active { display: list-item; }

/* ========================================
   Privacy Page
   ======================================== */
.privacy-content { max-width: 800px; margin: 0 auto; }
.privacy-content h2 { color: var(--text-dark); margin: 40px 0 20px; font-size: 1.4rem; }
.privacy-content p, .privacy-content ul { margin-bottom: 16px; line-height: 1.8; }
.privacy-content ul { padding-left: 24px; }
.privacy-content li { margin-bottom: 10px; line-height: 1.7; }
.privacy-content strong { color: var(--text-dark); }

/* ========================================
   Back to Top
   ======================================== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 46px;
    height: 46px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 1.2rem;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(33,150,243,0.3);
    transition: var(--transition);
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: center;
}
.back-to-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover { transform: translateY(-3px); box-shadow: 0 6px 20px rgba(33,150,243,0.4); }

/* ========================================
   Animations
   ======================================== */
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}
.fade-in-up { animation: fadeInUp 0.6s ease forwards; }

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 992px) {
    .hero-content { grid-template-columns: 1fr; text-align: center; }
    .hero-text h1 { font-size: 2.4rem; }
    .hero-text p { max-width: 100%; }
    .hero-btns { justify-content: center; }
    .hero-image { order: -1; }
    .hero-mockup { width: 300px; height: 420px; }
    .mockup-body { padding: 12px; gap: 10px; }
    .chat-bubble { max-width: 90%; }
    .bubble-text { padding: 8px 12px; font-size: 0.75rem; }
    .stats-grid { grid-template-columns: 1fr 1fr; gap: 30px; }
    .footer-grid { grid-template-columns: 1fr 1fr; gap: 40px; }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed; top: 72px; left: 0; right: 0;
        background: var(--bg-white); flex-direction: column;
        padding: 20px; gap: 4px;
        border-bottom: 1px solid var(--border);
        transform: translateY(-150%);
        transition: var(--transition); box-shadow: var(--shadow-md); z-index: 999;
    }
    .nav-menu.open { transform: translateY(0); }
    .nav-menu a { padding: 14px 20px; }
    .mobile-toggle { display: flex; }
    .section-header h2 { font-size: 1.8rem; }
    .hero { padding: 120px 0 60px; }
    .hero-text h1 { font-size: 2rem; }
    .features-grid, .news-grid { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr; gap: 30px; }
    .page-header h1 { font-size: 2rem; }
}

@media (max-width: 480px) {
    .hero-text h1 { font-size: 1.75rem; }
    .btn { padding: 14px 24px; font-size: 0.9rem; width: 100%; justify-content: center; }
    .hero-btns { flex-direction: column; }
    .stat-item h3 { font-size: 2.2rem; }
    .stat-item p { font-size: 0.9rem; }
}