body {
    font-family: 'Be Vietnam Pro', sans-serif;
    background-color: #0F172A; /* Slate 900 */
    color: #E2E8F0; /* Slate 200 */
    overflow-x: hidden;
}
/* Ensure language toggle button is visible against Tailwind reset */
.language-toggle {
    background: linear-gradient(135deg, #1e3c72, #2a5298) !important;
    border: 1px solid #4a90e2 !important;
    color: white !important;
    opacity: 1 !important;
    visibility: visible !important;
    display: inline-flex !important;
    align-items: center !important;
    justify-content: center !important;
}

h1, h2, h3, h4, .font-tech {
    font-family: 'Exo 2', sans-serif;
}

.media-placeholder {
    background-color: #1E293B;
    border: 2px dashed #475569;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #64748B;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}
.media-placeholder:hover {
    border-color: #06B6D4;
    color: #06B6D4;
    background-color: #1e293b80;
}

.video-container {
    position: relative;
    padding-bottom: 56.25%; /* 16:9 */
    height: 0;
    overflow: hidden;
    border-radius: 0.75rem;
    box-shadow: 0 0 20px rgba(6, 182, 212, 0.2);
}
.video-container iframe, 
.video-container .placeholder-content {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.chart-container {
    position: relative;
    width: 100%;
    max-width: 600px;
    margin: 0 auto;
    height: 350px;
}

.glass-panel {
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(56, 189, 248, 0.1);
}

/* --- TIMELINE CSS FIX --- */
/* Đường kẻ trung tâm */
.timeline-track {
    position: absolute;
    top: 50%;
    left: 0;
    width: 100%;
    height: 4px;
    background-color: #334155;
    transform: translateY(-50%);
    z-index: 0;
    border-radius: 9999px;
}

/* Chấm tròn trên Timeline */
.timeline-dot {
    width: 16px;
    height: 16px;
    border-radius: 50%;
    z-index: 10;
    position: relative;
    margin: 0 auto; /* Căn giữa ngang trong ô grid */
    border: 4px solid #0F172A; /* Viền trùng màu nền để tạo khoảng cách */
}

/* Đường kẻ dọc cho Mobile */
.timeline-vertical-line {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 20px; /* Vị trí của đường kẻ dọc */
    width: 2px;
    background-color: #334155;
}
.brand-logo {
    height: 34px;
    width: auto;
    filter: drop-shadow(0 0 9px #1ca7ab) brightness(1.3);
    transition: all 0.3s ease;
}

/* Fix Ko-fi button visibility */
.kofi-img {
    height: 36px !important;
    width: auto !important;
    max-width: none !important;
    display: inline-block !important;
    visibility: visible !important;
    opacity: 1 !important;
    vertical-align: middle !important;
}

/* ===== NAVBAR RESPONSIVE FIX ===== */

/* Desktop (≥992px) - Fix cho kích thước gần breakpoint */
@media screen and (min-width: 992px) {
    .navbar .container {
        display: flex !important;
        flex-wrap: nowrap !important;
        align-items: center !important;
    }
    
    .navbar-collapse {
        flex-wrap: nowrap !important;
    }
    
    .navbar-nav {
        flex-wrap: nowrap !important;
    }
    
    /* Desktop buttons group */
    .navbar .d-none.d-lg-block {
        flex-shrink: 0 !important;
        white-space: nowrap !important;
    }
}

/* Desktop nhỏ (992px - 1100px) - Thu nhỏ elements */
@media screen and (min-width: 992px) and (max-width: 1100px) {
    .brand-logo {
        height: 28px !important;
    }
    
    .kofi-img {
        height: 30px !important;
    }
    
    .nav-link {
        padding-left: 0.5rem !important;
        padding-right: 0.5rem !important;
        font-size: 14px !important;
    }
    
    .language-toggle {
        padding: 4px 8px !important;
        font-size: 12px !important;
    }
}

/* Base navbar fix - ÁP DỤNG CHO TẤT CẢ màn hình dưới 992px */
@media screen and (max-width: 991px) {
    /* Container phải là flex và không wrap */
    .navbar .container,
    .navbar.fixed-top .container,
    .navbar > .container {
        display: flex !important;
        flex-wrap: nowrap !important;
        flex-direction: row !important;
        align-items: center !important;
        justify-content: space-between !important;
        width: 100% !important;
        max-width: 100% !important;
        height: 100% !important;
    }
    
    /* Navbar brand - cho phép co lại */
    .navbar-brand,
    .navbar .navbar-brand {
        flex: 0 1 auto !important;
        min-width: 0 !important;
        overflow: hidden !important;
        margin-right: auto !important;
    }
    
    /* Nhóm buttons bên phải - KHÔNG được co lại */
    .navbar .d-flex.d-lg-none,
    .navbar .d-flex.align-items-center.d-lg-none {
        flex: 0 0 auto !important;
        flex-shrink: 0 !important;
        flex-wrap: nowrap !important;
        display: flex !important;
        align-items: center !important;
        margin-left: auto !important;
        white-space: nowrap !important;
    }
    
    /* Navbar collapse menu dropdown */
    .navbar-collapse {
        position: absolute !important;
        top: 56px !important;
        left: 0 !important;
        right: 0 !important;
        width: 100% !important;
        background: linear-gradient(135deg, #050a30 0%, #0a1445 100%) !important;
        border-radius: 0 0 8px 8px !important;
        padding: 15px !important;
        box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3) !important;
        z-index: 1000 !important;
    }
    
    .navbar-collapse .navbar-nav {
        flex-direction: column !important;
        align-items: flex-start !important;
    }
    
    .navbar-collapse .nav-item {
        width: 100% !important;
        border-bottom: 1px solid rgba(255, 255, 255, 0.1) !important;
    }
    
    .navbar-collapse .nav-item:last-child {
        border-bottom: none !important;
    }
    
    .navbar-collapse .nav-link {
        padding: 12px 0 !important;
    }
    
    /* Hamburger button */
    .navbar-toggler {
        border-color: rgba(6, 182, 212, 0.5) !important;
        padding: 4px 8px !important;
        flex-shrink: 0 !important;
    }
    
    .navbar-toggler:focus {
        box-shadow: 0 0 10px rgba(6, 182, 212, 0.5) !important;
    }
    
    .navbar-toggler-icon {
        width: 1.2em !important;
        height: 1.2em !important;
    }
}

/* Tablet: 768px - 991px */
@media screen and (min-width: 768px) and (max-width: 991px) {
    .brand-logo {
        height: 30px !important;
    }
    .kofi-img {
        height: 32px !important;
    }
    .language-toggle {
        padding: 5px 12px !important;
        font-size: 13px !important;
    }
    .navbar .d-flex.d-lg-none {
        gap: 8px !important;
    }
}

/* Small tablet: 576px - 767px */
@media screen and (min-width: 576px) and (max-width: 767px) {
    .brand-logo {
        height: 26px !important;
    }
    .kofi-img {
        height: 28px !important;
    }
    .language-toggle {
        padding: 4px 10px !important;
        font-size: 12px !important;
    }
    .navbar .d-flex.d-lg-none {
        gap: 6px !important;
    }
}

/* Mobile: dưới 576px */
@media screen and (max-width: 575px) {
    .navbar.fixed-top,
    nav.navbar {
        height: 50px !important;
        min-height: 50px !important;
        max-height: 50px !important;
    }
    
    .navbar .container {
        padding-left: 10px !important;
        padding-right: 10px !important;
    }
    
    .navbar-collapse {
        top: 50px !important;
    }
    
    .brand-logo {
        height: 20px !important;
    }
    
    .kofi-img {
        height: 24px !important;
    }
    
    .language-toggle {
        padding: 3px 6px !important;
        font-size: 11px !important;
    }
    
    .navbar-toggler {
        padding: 2px 5px !important;
    }
    
    .navbar-toggler-icon {
        width: 1em !important;
        height: 1em !important;
    }
    
    .navbar .d-flex.d-lg-none {
        gap: 4px !important;
    }
}