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

body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    overflow: hidden;
    height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Thanh Topbar màu xanh đen */
.topbar {
    background-color: #0f1e40;
    height: 50px;
    display: flex;
    align-items: center;
    padding: 0 15px;
    z-index: 100;
}

.topbar-left {
    display: flex;
    align-items: center;
    gap: 12px;
}

.menu-btn {
    background: none;
    border: none;
    color: white;
    font-size: 24px;
    cursor: pointer;
    outline: none;
    padding: 5px;
    display: flex;
    align-items: center;
}

/* Nút Reset trên topbar */
.reset-topbar-btn {
    background: rgba(255, 255, 255, 0.12);
    border: 1px solid rgba(255, 255, 255, 0.25);
    color: white;
    padding: 5px 12px;
    border-radius: 16px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 13px;
    font-weight: 500;
    transition: all 0.2s ease;
}

.reset-topbar-btn:hover {
    background: rgba(255, 255, 255, 0.25);
}

/* Container */
.main-container {
    position: relative;
    flex: 1;
    display: flex;
    background-color: #ffffff;
}

/* Sidebar ẩn sẵn sang bên trái */
.sidebar {
    position: absolute;
    top: 0;
    left: -250px;
    width: 250px;
    height: 100%;
    background-color: #a3a3a3;
    padding: 20px 15px;
    display: flex;
    flex-direction: column;
    gap: 15px;
    transition: left 0.3s ease;
    z-index: 10;
}

.sidebar.active {
    left: 0;
}

.nav-btn {
    background-color: transparent;
    border: 1px solid #1a2a4a;
    border-radius: 20px;
    padding: 10px 15px;
    color: #1a2a4a;
    font-weight: bold;
    font-size: 14px;
    text-align: left;
    cursor: pointer;
    transition: all 0.2s ease;
}

.nav-btn:hover, .nav-btn.active {
    background-color: rgba(255, 255, 255, 0.4);
}

/* Khu vực hiển thị nội dung */
.iframe-wrapper {
    width: 100%;
    height: 100%;
    position: relative;
    background-color: #ffffff;
}

.content-area {
    width: 100%;
    height: 100%;
    border: none;
    position: absolute;
    top: 0;
    left: 0;
    display: none;
}

.content-area.active {
    display: block;
}

/* Popup Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: rgba(0, 0, 0, 0.45);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 999;
    opacity: 0;
    visibility: hidden;
    transition: all 0.25s ease;
}

.modal-overlay.show {
    opacity: 1;
    visibility: visible;
}

.modal-card {
    background-color: #ffffff;
    width: 90%;
    max-width: 380px;
    padding: 28px 24px 22px;
    border-radius: 16px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.15);
    text-align: center;
    transform: scale(0.9);
    transition: transform 0.25s ease;
}

.modal-overlay.show .modal-card {
    transform: scale(1);
}

.modal-title {
    color: #1e293b;
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 12px;
}

.modal-desc {
    color: #64748b;
    font-size: 13.5px;
    line-height: 1.5;
    margin-bottom: 24px;
}

.modal-actions {
    display: flex;
    gap: 12px;
    justify-content: center;
}

.btn-cancel {
    flex: 1;
    padding: 10px 16px;
    border-radius: 10px;
    border: none;
    background-color: #f1f5f9;
    color: #334155;
    font-weight: 600;
    font-size: 14px;
    cursor: pointer;
    transition: background 0.2s;
}

.btn-cancel:hover {
    background-color: #e2e8f0;
}

.btn-confirm {
    flex: 1;
    padding: 10px 16px;
    border-radius: 10px;
    border: none;
    background-color: #ef4444;
    color: white;
    font-weight: 600;
    font-size: 14px;
    cursor: pointer;
    transition: background 0.2s;
}

.btn-confirm:hover {
    background-color: #dc2626;
}