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

body {
    font-family: 'Segoe UI', 'Roboto', 'Helvetica Neue', sans-serif;
    background: linear-gradient(145deg, #eef2f9 0%, #e0e8f2 100%);
    min-height: 100vh;
    padding: 24px;
}

.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
}

/* ========== HEADER 2 CỘT ========== */
.app-header {
    background: linear-gradient(135deg, #6ec3ff 0%, #3b9eff 100%);
    border-radius: 40px;
    padding: 40px 48px;
    display: flex;
    align-items: center;
    gap: 48px;
    box-shadow: 0 20px 35px -12px rgba(0, 100, 200, 0.25);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.app-header:hover {
    transform: translateY(-4px);
    box-shadow: 0 28px 40px -12px rgba(0, 100, 200, 0.35);
}

.header-left {
    flex: 0 0 auto;
    display: flex;
    justify-content: center;
    align-items: center;
}

.header-icon {
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(8px);
    border-radius: 100px;
    padding: 28px;
    box-shadow: 0 10px 20px -5px rgba(0, 0, 0, 0.1);
}

.app-logo {
    display: block;
    height: 220px;
    width: auto;
    transition: transform 0.2s;
}

.app-header:hover .app-logo {
    transform: scale(1.02);
}

.header-right {
    flex: 1;
    text-align: center;
}

#appName {
    font-size: 2.5rem;
    font-weight: 800;
    color: white;
    letter-spacing: -0.5px;
    text-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    margin-bottom: 16px;
}

.welcome-message {
    font-size: 1.1rem;
    font-weight: 500;
    color: rgba(255, 255, 255, 0.95);
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(4px);
    display: inline-block;
    padding: 10px 24px;
    border-radius: 50px;
    margin-bottom: 24px;
    line-height: 1.4;
}

.features {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
    margin-bottom: 28px;
}

.feature-item {
    background: rgba(255, 255, 255, 0.25);
    backdrop-filter: blur(4px);
    padding: 6px 18px;
    border-radius: 40px;
    font-size: 0.95rem;
    font-weight: 500;
    color: white;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: all 0.2s;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.feature-emoji {
    font-size: 1rem;
}

.feature-item:hover {
    background: rgba(255, 255, 255, 0.4);
    transform: scale(1.02);
}

.google-play-btn {
    display: inline-block;
    transition: all 0.2s ease;
}

.google-play-btn img {
    height: 64px;
    width: auto;
    border-radius: 16px;
    transition: transform 0.2s, box-shadow 0.2s;
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.1);
}

.google-play-btn:hover img {
    transform: scale(1.03);
    box-shadow: 0 12px 20px rgba(0, 0, 0, 0.15);
}

/* ========== MAIN FEATURES ========== */
.main-features {
    margin-top: 56px;
    text-align: center;
}

.features-header {
    margin-bottom: 48px;
}

.features-header h2 {
    font-size: 2.4rem;
    font-weight: 800;
    background: linear-gradient(135deg, #1e3a5f, #2b5a8c);
    background-clip: text;
    -webkit-background-clip: text;
    color: transparent;
    letter-spacing: -0.5px;
    margin-bottom: 12px;
}

.features-sub {
    font-size: 1.15rem;
    color: #4a627a;
    font-weight: 500;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
}

.feature-card {
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(12px);
    border-radius: 32px;
    padding: 28px 24px;
    text-align: left;
    box-shadow: 0 20px 35px -12px rgba(0, 0, 0, 0.1);
    transition: all 0.3s cubic-bezier(0.2, 0.9, 0.4, 1.1);
    border: 1px solid rgba(255, 255, 255, 0.5);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 30px 40px -12px rgba(0, 0, 0, 0.2);
    background: rgba(255, 255, 255, 0.85);
    border-color: rgba(59, 158, 255, 0.4);
}

.card-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: #1e3a5f;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 12px;
    border-bottom: 2px solid rgba(59, 158, 255, 0.3);
    padding-bottom: 14px;
}

.card-title i {
    font-size: 1.8rem;
    color: #3b9eff;
    background: rgba(59, 158, 255, 0.15);
    padding: 10px;
    border-radius: 20px;
    transition: all 0.2s;
}

.feature-card:hover .card-title i {
    background: rgba(59, 158, 255, 0.25);
    transform: scale(1.05);
}

.feature-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.feature-list li {
    margin-bottom: 16px;
    font-size: 0.95rem;
    color: #2c3e4e;
    display: flex;
    align-items: flex-start;
    gap: 12px;
}

.feature-list li i {
    color: #3b9eff;
    font-size: 1rem;
    margin-top: 2px;
    min-width: 20px;
    background: none;
    padding: 0;
}

.feature-list li span {
    line-height: 1.4;
    font-weight: 500;
}

/* ========== UNIQUE FEATURES ========== */
.unique-features {
    margin-top: 72px;
    text-align: center;
}

.unique-header h2 {
    font-size: 2.4rem;
    font-weight: 800;
    background: linear-gradient(135deg, #1e3a5f, #2b5a8c);
    background-clip: text;
    -webkit-background-clip: text;
    color: transparent;
    margin-bottom: 12px;
}

.unique-sub {
    font-size: 1.15rem;
    color: #4a627a;
    margin-bottom: 48px;
    font-weight: 500;
}

.unique-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 28px;
}

.unique-card {
    background: rgba(255, 255, 255, 0.6);
    backdrop-filter: blur(12px);
    border-radius: 32px;
    padding: 28px 24px;
    text-align: center;
    transition: all 0.3s ease;
    border: 1px solid rgba(255, 255, 255, 0.5);
    box-shadow: 0 10px 20px -8px rgba(0, 0, 0, 0.05);
}

.unique-card:hover {
    transform: translateY(-6px);
    background: rgba(255, 255, 255, 0.85);
    box-shadow: 0 25px 35px -12px rgba(0, 0, 0, 0.15);
    border-color: rgba(59, 158, 255, 0.4);
}

.unique-icon {
    font-size: 2.5rem;
    color: #3b9eff;
    background: rgba(59, 158, 255, 0.12);
    width: 70px;
    height: 70px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 30px;
    margin: 0 auto 20px;
    transition: all 0.2s;
}

.unique-card:hover .unique-icon {
    background: rgba(59, 158, 255, 0.25);
    transform: scale(1.05);
}

.unique-card h3 {
    font-size: 1.3rem;
    font-weight: 700;
    color: #1e3a5f;
    margin-bottom: 12px;
}

.unique-card p {
    font-size: 0.95rem;
    color: #2c4c6c;
    line-height: 1.5;
}

/* ========== FOOTER ========== */
.app-footer {
    margin-top: 80px;
    background: rgba(255, 255, 255, 0.5);
    backdrop-filter: blur(8px);
    border-radius: 40px;
    padding: 40px 32px;
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.6);
}

.footer-thanks {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1e3a5f;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
}

.footer-thanks i {
    font-size: 1.6rem;
    color: #ff6b6b;
}

.contact-info {
    display: flex;
    justify-content: center;
    margin-bottom: 28px;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1rem;
    color: #2c3e4e;
    background: rgba(255, 255, 255, 0.4);
    padding: 8px 20px;
    border-radius: 50px;
    transition: all 0.2s;
}

.contact-item i {
    font-size: 1.2rem;
    color: #3b9eff;
}

.contact-item:hover {
    background: rgba(255, 255, 255, 0.8);
    transform: translateY(-2px);
}

/* ========== RESPONSIVE ========== */
@media (max-width: 768px) {
    body {
        padding: 16px;
    }

    .app-header {
        flex-direction: column;
        text-align: center;
        padding: 32px 24px;
        gap: 24px;
    }
    .header-right {
        text-align: center;
    }
    .features {
        justify-content: center;
    }
    .header-icon {
        padding: 20px;
        border-radius: 80px;
    }
    .app-logo {
        height: 160px;
    }
    #appName {
        font-size: 2rem;
    }
    .welcome-message {
        font-size: 1rem;
        padding: 8px 20px;
    }
    .feature-item {
        font-size: 0.85rem;
        padding: 5px 14px;
    }
    .google-play-btn img {
        height: 54px;
    }

    .main-features {
        margin-top: 40px;
    }
    .features-header h2 {
        font-size: 1.9rem;
    }
    .features-sub {
        font-size: 1rem;
    }
    .features-grid {
        gap: 24px;
    }
    .feature-card {
        padding: 24px 20px;
    }
    .card-title {
        font-size: 1.3rem;
    }
    .card-title i {
        font-size: 1.5rem;
    }
    .feature-list li {
        font-size: 0.9rem;
    }

    .unique-features {
        margin-top: 48px;
    }
    .unique-header h2 {
        font-size: 1.9rem;
    }
    .unique-grid {
        gap: 20px;
    }
    .unique-card {
        padding: 24px 20px;
    }
    .app-footer {
        margin-top: 48px;
        padding: 32px 20px;
    }
    .contact-item {
        padding: 6px 16px;
        font-size: 0.85rem;
    }
    .footer-thanks {
        font-size: 1.1rem;
    }
}

@media (max-width: 480px) {
    .app-logo {
        height: 130px;
    }
    #appName {
        font-size: 1.6rem;
    }
    .welcome-message {
        font-size: 0.9rem;
    }
    .feature-item {
        font-size: 0.75rem;
        padding: 4px 12px;
    }
    .google-play-btn img {
        height: 48px;
    }

    .features-header h2 {
        font-size: 1.6rem;
    }
    .features-sub {
        font-size: 0.9rem;
    }
    .feature-card {
        padding: 20px 16px;
    }
    .card-title {
        font-size: 1.2rem;
        margin-bottom: 16px;
    }
    .card-title i {
        font-size: 1.3rem;
        padding: 6px;
    }
    .feature-list li {
        font-size: 0.85rem;
        gap: 8px;
    }

    .unique-header h2 {
        font-size: 1.6rem;
    }
    .unique-sub {
        font-size: 0.9rem;
    }
    .unique-card h3 {
        font-size: 1.1rem;
    }
    .unique-card p {
        font-size: 0.85rem;
    }
    .footer-thanks {
        font-size: 1rem;
    }
    .contact-item {
        padding: 4px 12px;
        font-size: 0.75rem;
    }
}