.nexus-unified-mobile-toolbar {
    position: fixed;
    bottom: 16px;
    left: 16px;
    right: 16px;
    height: 64px;
    border-radius: 16px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 0.5rem;
    z-index: 1000;
    box-sizing: border-box;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    overflow: visible; /* Critical to show elevated FAB */
}

/* Light Mode: Premium Paper Look */
.nexus-unified-mobile-toolbar.theme-light {
    background: rgba(244, 241, 234, 0.9);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(139, 130, 115, 0.18);
    box-shadow: 0 8px 30px rgba(139, 130, 115, 0.15);
}

/* Dark Mode: Translucent Slate */
.nexus-unified-mobile-toolbar.theme-dark {
    background: rgba(18, 18, 18, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.08);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.5);
}

.nav-toggle-btn {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: none;
    border: none;
    color: #8b8273; /* Inactive items earthy gray */
    padding: 6px 0;
    cursor: pointer;
    transition: all 0.2s ease;
    min-width: 0;
    position: relative;
    height: 100%;
}

.nav-toggle-btn.active {
    color: #10b981; /* Active items vibrant green */
}

.nav-toggle-btn ::deep .nexus-icon {
    transition: transform 0.2s ease;
}

.nav-toggle-btn.active ::deep .nexus-icon {
    transform: scale(1.1);
}

.tab-label {
    font-size: 11px;
    font-weight: 500;
    margin-top: 4px;
    white-space: nowrap;
}

.progress-ring-wrapper {
    position: relative;
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.progress-ring {
    transform: rotate(-90deg);
}

.progress-text {
    position: absolute;
    font-size: 0.6rem;
    font-weight: 700;
    color: #8b8273;
}

.nav-toggle-btn.active .progress-text {
    color: #10b981;
}

/* Center AI FAB container & button */
.center-ai-container {
    overflow: visible;
}

.btn-nexus-ai-core {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    border: none;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #ffffff;
    cursor: pointer;
    position: absolute;
    top: -20px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 5;
    box-shadow: 0 4px 14px rgba(16, 185, 129, 0.4);
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.btn-nexus-ai-core:active {
    transform: translateX(-50%) translateY(-18px) scale(0.95);
    box-shadow: 0 2px 8px rgba(16, 185, 129, 0.3);
}

.ai-core-icon {
    color: #ffffff !important;
}

.center-ai-container .tab-label {
    margin-top: 32px;
}

/* Pulse effects */
.pulse-ring {
    position: absolute;
    top: -4px;
    left: -4px;
    right: -4px;
    bottom: -4px;
    border-radius: 50%;
    border: 2px solid rgba(16, 185, 129, 0.4);
    opacity: 0;
    animation: corePulse 2s cubic-bezier(0.24, 0, 0.38, 1) infinite;
    pointer-events: none;
    z-index: 1;
}

.pulse-ring-outer {
    position: absolute;
    top: -8px;
    left: -8px;
    right: -8px;
    bottom: -8px;
    border-radius: 50%;
    border: 1px solid rgba(16, 185, 129, 0.2);
    opacity: 0;
    animation: corePulseOuter 2.5s cubic-bezier(0.24, 0, 0.38, 1) infinite;
    pointer-events: none;
    z-index: 1;
}

@keyframes corePulse {
    0% { transform: scale(0.95); opacity: 0; }
    50% { opacity: 0.8; }
    100% { transform: scale(1.15); opacity: 0; }
}

@keyframes corePulseOuter {
    0% { transform: scale(0.9); opacity: 0; }
    50% { opacity: 0.5; }
    100% { transform: scale(1.25); opacity: 0; }
}


/* SECTION CHECKPOINTS OVERLAY */
.checkpoints-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: 1400;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    pointer-events: none;
}

.checkpoints-overlay.is-open {
    pointer-events: all;
}

.checkpoints-backdrop {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(3px);
    opacity: 0;
    transition: opacity 0.3s ease;
    z-index: 1;
}

.checkpoints-overlay.is-open .checkpoints-backdrop {
    opacity: 1;
}

.checkpoints-sheet {
    position: relative;
    width: 100%;
    max-height: 50vh;
    background: rgba(15, 15, 15, 0.9);
    backdrop-filter: blur(20px);
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    border-top-left-radius: 16px;
    border-top-right-radius: 16px;
    box-shadow: 0 -8px 30px rgba(0, 0, 0, 0.5);
    z-index: 2;
    transform: translateY(100%);
    transition: transform 0.35s cubic-bezier(0.16, 1, 0.3, 1);
    display: flex;
    flex-direction: column;
}

.checkpoints-overlay.is-open .checkpoints-sheet {
    transform: translateY(0);
}

.checkpoints-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1.25rem;
    border-bottom: 1px solid rgba(255,255,255,0.06);
}

.checkpoints-header h4 {
    font-size: 0.9rem;
    font-weight: 600;
    color: #FFFFFF;
    margin: 0;
}

.close-checkpoints-btn {
    background: none;
    border: none;
    color: rgba(255,255,255,0.5);
    padding: 4px;
    cursor: pointer;
    display: flex;
    align-items: center;
}

.checkpoints-body {
    flex: 1;
    overflow-y: auto;
    padding: 1rem 1.25rem;
}

.empty-checkpoints {
    text-align: center;
    padding: 2rem 1rem;
    color: rgba(255,255,255,0.4);
}

.empty-checkpoints p {
    font-size: 0.8rem;
    margin-top: 0.5rem;
}

.checkpoints-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    padding-bottom: 1rem;
}

.checkpoint-item {
    display: flex;
    align-items: center;
    padding: 0.75rem;
    border-radius: 10px;
    background-color: rgba(255,255,255,0.02);
    border: 1px solid rgba(255,255,255,0.04);
    cursor: pointer;
    transition: all 0.2s ease;
}

.checkpoint-item:active {
    background-color: rgba(255,255,255,0.05);
}

.checkpoint-item.active {
    background-color: rgba(0, 255, 153, 0.04);
    border-color: rgba(0, 255, 153, 0.15);
}

.checkpoint-indicator {
    width: 14px;
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-right: 0.75rem;
}

.indicator-dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background-color: rgba(255,255,255,0.3);
}

.checkpoint-item.active .indicator-dot {
    background-color: var(--nexus-neon, #00FF99);
    box-shadow: 0 0 8px rgba(0, 255, 153, 0.6);
}

.checkpoint-details {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.checkpoint-id {
    font-size: 0.8rem;
    font-weight: 700;
    color: #FFFFFF;
}

.checkpoint-item.active .checkpoint-id {
    color: var(--nexus-neon, #00FF99);
}

.checkpoint-label {
    font-size: 0.65rem;
    color: rgba(255,255,255,0.4);
    margin-top: 1px;
}

.arrow-icon {
    color: rgba(255,255,255,0.25);
    transition: transform 0.2s ease;
}

.checkpoint-item:active .arrow-icon {
    transform: translateX(2px);
}

/* Light Mode overrides for Checkpoints Overlay */
.theme-light .checkpoints-sheet {
    background: rgba(244, 241, 234, 0.95);
    border-top: 1px solid rgba(139, 130, 115, 0.15);
    box-shadow: 0 -8px 30px rgba(139, 130, 115, 0.15);
}

.theme-light .checkpoints-header {
    border-bottom: 1px solid rgba(139, 130, 115, 0.1);
}

.theme-light .checkpoints-header h4 {
    color: #292524;
}

.theme-light .close-checkpoints-btn {
    color: #8b8273;
}

.theme-light .checkpoint-item {
    background-color: rgba(139, 130, 115, 0.03);
    border: 1px solid rgba(139, 130, 115, 0.06);
}

.theme-light .checkpoint-item.active {
    background-color: rgba(16, 185, 129, 0.08);
    border-color: rgba(16, 185, 129, 0.25);
}

.theme-light .checkpoint-item.active .checkpoint-id {
    color: #10b981;
}

.theme-light .checkpoint-item.active .indicator-dot {
    background-color: #10b981;
    box-shadow: 0 0 8px rgba(16, 185, 129, 0.6);
}

.theme-light .checkpoint-id {
    color: #292524;
}

.theme-light .checkpoint-label {
    color: #8b8273;
}

.theme-light .arrow-icon {
    color: #8b8273;
}