:root {
    --bg-dark: #0f172a;
    --bg-card: rgba(30, 41, 59, 0.7);
    --primary: #38bdf8;
    --secondary: #818cf8;
    --accent: #f472b6;
    --text-main: #f1f5f9;
    --text-dim: #94a3b8;
    --glass: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    
    /* Status Colors */
    --status-1: #ef4444; /* 🟥 Red */
    --status-2: #f97316; /* 🟧 Orange */
    --status-3: #facc15; /* 🟨 Yellow */
    --status-4: #22c55e; /* 🟩 Green */
    
    --shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    --radius: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

body {
    background: var(--bg-dark);
    color: var(--text-main);
    background-image: 
        radial-gradient(at 0% 0%, rgba(56, 189, 248, 0.15) 0px, transparent 50%),
        radial-gradient(at 100% 100%, rgba(129, 140, 248, 0.15) 0px, transparent 50%);
    min-height: 100vh;
    overflow-x: hidden;
}

/* Glassmorphism Sidebar/Nav */
nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 260px;
    height: 100vh;
    background: var(--bg-card);
    backdrop-filter: blur(12px);
    border-right: 1px solid var(--glass-border);
    padding: 2rem 1rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    z-index: 100;
}

main {
    margin-left: 260px;
    padding: 2rem;
    max-width: 1200px;
}

.nav-item {
    padding: 12px 16px;
    border-radius: var(--radius);
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-dim);
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
}

.nav-item:hover, .nav-item.active {
    background: var(--glass);
    color: var(--primary);
    border: 1px solid var(--glass-border);
}

.nav-item.active {
    box-shadow: inset 0 0 10px rgba(56, 189, 248, 0.1);
}

/* Tabs and Content Area */
.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
    animation: fadeIn 0.4s ease-out;
}

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

/* Cards & Forms */
.card {
    background: var(--bg-card);
    backdrop-filter: blur(8px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow);
}

h1, h2, h3 {
    margin-bottom: 1rem;
    font-weight: 700;
}

.title-gradient {
    background: linear-gradient(to right, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Form Elements */
.form-group {
    margin-bottom: 1.25rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-dim);
    font-size: 0.9rem;
}

input, select, textarea {
    width: 100%;
    background: rgba(15, 23, 42, 0.5);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    padding: 10px 14px;
    color: var(--text-main);
    transition: var(--transition);
    min-width: 80px;
}

input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(56, 189, 248, 0.2);
}

.btn {
    padding: 10px 20px;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(56, 189, 248, 0.3);
}

/* Question List Layout */
.question-item {
    display: flex;
    gap: 1rem;
    align-items: flex-start;
}

.status-indicator {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    margin-top: 6px;
    flex-shrink: 0;
}

.status-1 { background: var(--status-1); }
.status-2 { background: var(--status-2); }
.status-3 { background: var(--status-3); }
.status-4 { background: var(--status-4); }

/* Status Step Picker */
.status-picker {
    display: flex;
    gap: 8px;
    margin-top: 10px;
}

.status-dot {
    width: 24px;
    height: 24px;
    border-radius: 4px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    opacity: 0.3;
    transition: var(--transition);
}

.status-dot.active {
    opacity: 1;
    transform: scale(1.1);
}

/* Filters */
.filters-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

/* Sliding Toggle for Part */
.part-toggle {
    display: flex;
    background: rgba(15, 23, 42, 0.5);
    border-radius: 8px;
    padding: 4px;
    width: fit-content;
}

.part-option {
    padding: 6px 20px;
    border-radius: 6px;
    cursor: pointer;
    transition: var(--transition);
}

.part-option.active {
    background: var(--primary);
    color: white;
}

/* Multi-Add Field */
.multi-field {
    border-left: 2px solid var(--primary);
    padding-left: 1rem;
    margin-bottom: 1rem;
}

/* Responsive */
@media (max-width: 992px) {
    main { padding: 1.5rem; }
}

@media (max-width: 768px) {
    .nav-header { display: none; }
    
    html { font-size: 14px; } /* Global scaling */
    
    nav {
        width: 100%;
        height: 60px;
        flex-direction: row;
        top: auto;
        bottom: 0;
        padding: 0;
        justify-content: space-around;
        align-items: center;
        border-right: none;
        border-top: 1px solid var(--glass-border);
        border-radius: 20px 20px 0 0;
    }
    
    .nav-item {
        flex-direction: column;
        gap: 4px;
        padding: 8px;
        flex: 1;
        border-radius: 0;
        font-size: 0.7rem;
        background: transparent !important;
        border: none !important;
        box-shadow: none !important;
    }
    
    .nav-item i { font-size: 1.2rem; }
    .nav-item span { display: block; font-size: 0.65rem; }

    main {
        margin-left: 0;
        margin-bottom: 70px;
        padding: 1rem;
        width: 100%;
    }

    .card { padding: 1rem; }
    
    /* Study Room Specifics */
    .study-filter-container {
        flex-direction: column;
        gap: 20px;
    }
    
    .filter-card-left, .filter-card-right {
        width: 100% !important;
    }

    .subject-slide {
        padding: 8px 15px;
        font-size: 0.75rem;
    }

    /* Merged Nav stacking */
    .merged-nav {
        flex-direction: column;
    }
    .merged-nav-item {
        border-right: none;
        border-bottom: 1px solid var(--glass-border);
    }
    
    /* Grid Adjustments */
    .params-grid, #params-legacy, #params-common {
        grid-template-columns: 1fr !important;
    }
    
    .dashboard-grid {
        grid-template-columns: 1fr !important;
    }

    /* Parameter lists adjustments */
    .param-list {
        max-height: none !important;
    }
    
    .param-item {
        padding: 10px;
    }
    
    .param-item span {
        font-size: 0.85rem;
    }

    /* Modal spacing */
    .modal {
        padding: 1.5rem;
        width: 95%;
    }
    
    /* Subject structure preview */
    #subject-preview-container {
        padding: 0;
    }
    #subject-preview-container > div {
        padding: 10px !important;
    }
}

@media (max-width: 480px) {
    .btn {
        width: 100%;
        justify-content: center;
        padding: 12px;
    }
    
    .grid-layout {
        grid-template-columns: repeat(4, 1fr) !important;
    }
}