/* global (Light Theme Default)*/
:root {
    --main-font-family: 'Inter', 'Segoe UI', sans-serif;
    --main-font-size: 16px;

    --primary: #4F46E5;       
    --primary-hover: #4338CA; 
    --primary-light: #E0E7FF; 
    
    --bg-main: #F8FAFC;       
    --bg-card: #FFFFFF;       
    --sidebar-bg: #1E293B;    
    --sidebar-hover: #334155; 
    
    --text-main: #0F172A;     
    --text-muted: #64748B;    
    --text-light: #F8FAFC;    
    
    --border-color: #E2E8F0;
    --input-border: #CBD5E1;
    --input-bg: #FFFFFF;
    --hover-bg: #F1F5F9;
    
    --success: #10B981;       
    --success-hover: #059669; 
    --danger: #EF4444;        
    --danger-hover: #DC2626;  
    --warning: #F59E0B;       
    --warning-hover: #D97706; 
    
    --border-radius: 10px;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    --transition: all 0.2s ease-in-out;
}

/* dark mode */
body.dark-mode {
    --bg-main: #0F172A;       
    --bg-card: #1E293B;       
    --sidebar-bg: #020617;    
    --sidebar-hover: #1E293B; 
    
    --text-main: #F8FAFC;     
    --text-muted: #94A3B8;    
    
    --border-color: #334155;  
    --input-border: #475569;
    --input-bg: #0F172A;      
    --hover-bg: #334155;
    
    --primary-light: #312E81; 
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.4);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.4);
}

body { 
    font-family: var(--main-font-family); /* Updated to use variable */
    font-size: var(--main-font-size);     /* Updated to use variable */
    margin: 0; 
    display: flex; 
    height: 100vh; 
    background-color: var(--bg-main); 
    color: var(--text-main);
    transition: background-color 0.3s, color 0.3s;
}

h1, h2, h3, h4 { color: var(--text-main); margin-top: 0; }
a { text-decoration: none; color: var(--primary); }

/*  layout and slders */
.sidebar { 
    width: 250px; 
    background-color: var(--sidebar-bg); 
    color: var(--text-light); 
    display: flex; 
    flex-direction: column; 
    padding: 24px; 
    box-shadow: var(--shadow-md);
    z-index: 10;
    transition: background-color 0.3s;
}

.sidebar h2 { font-size: 1.5rem; text-align: center; margin-bottom: 2rem; color: var(--text-light); font-weight: 700; }

.nav-btn { 
    background: transparent; border: none; color: #CBD5E1; padding: 12px 16px; 
    text-align: left; cursor: pointer; font-size: 1.05rem; transition: var(--transition); 
    border-radius: 8px; margin-bottom: 8px; width: 100%; display: block; box-sizing: border-box;
}

.nav-btn:hover, .nav-btn.active { background-color: var(--sidebar-hover); color: #fff; font-weight: 600; }

.logout { margin-top: auto; color: #FCA5A5; }
.logout:hover { background-color: rgba(239, 68, 68, 0.1); color: var(--danger); }

.main { flex: 1; padding: 40px; overflow-y: auto; }

/*   cards, forms & inouts */
.card { 
    background: var(--bg-card); padding: 24px; border-radius: var(--border-radius); 
    box-shadow: var(--shadow-sm); margin-bottom: 24px; border: 1px solid var(--border-color);
    transition: background-color 0.3s, border-color 0.3s;
}

.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-bottom: 15px; }

label { display: block; margin-bottom: 6px; font-size: 0.9rem; font-weight: 600; color: var(--text-muted); }

input, select, textarea { 
    width: 100%; padding: 10px 12px; border: 1px solid var(--input-border); 
    border-radius: 6px; box-sizing: border-box; font-size: 0.95rem;
    background-color: var(--input-bg); color: var(--text-main);
    transition: var(--transition); font-family: inherit;
}
input[type="time"], input[type="date"] { color-scheme: light dark; }
body.dark-mode input[type="time"], body.dark-mode input[type="date"] { color-scheme: dark; }

input:focus, select:focus, textarea:focus { outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-light); }

/* buttons */
button { font-family: inherit; font-weight: 500; }

button.primary, .btn-save, .generate-btn { 
    background-color: var(--primary); color: white; border: none; padding: 10px 20px; 
    border-radius: 6px; cursor: pointer; font-size: 1rem; transition: var(--transition);
}
button.primary:hover, .btn-save:hover { background-color: var(--primary-hover); }

.btn-delete { background-color: rgba(239, 68, 68, 0.1); color: var(--danger); border: 1px solid rgba(239, 68, 68, 0.3); padding: 6px 12px; border-radius: 6px; cursor: pointer; transition: var(--transition); }
.btn-delete:hover { background-color: var(--danger); color: white; border-color: var(--danger); }

.btn-edit { background-color: rgba(245, 158, 11, 0.1); color: var(--warning); border: 1px solid rgba(245, 158, 11, 0.3); padding: 6px 12px; border-radius: 6px; cursor: pointer; transition: var(--transition); }
.btn-edit:hover { background-color: var(--warning); color: white; border-color: var(--warning); }

.btn-magic { background: linear-gradient(135deg, #8B5CF6, #6D28D9); color: white; border: none; padding: 10px; border-radius: 6px; cursor: pointer; width: 100%; margin-top:10px; font-weight: 600; transition: var(--transition); }
.btn-magic:hover { opacity: 0.9; box-shadow: var(--shadow-md); transform: translateY(-1px); }

/* tables and badges */
table { width: 100%; border-collapse: collapse; margin-top: 10px; font-size: 0.95rem; }
th, td { text-align: left; padding: 14px 12px; border-bottom: 1px solid var(--border-color); }
th { background-color: var(--bg-main); color: var(--text-muted); font-weight: 600; text-transform: uppercase; font-size: 0.8rem; letter-spacing: 0.05em; }
tr:hover td { background-color: var(--hover-bg); }

.badge { padding: 4px 10px; border-radius: 20px; font-size: 0.8rem; font-weight: 600; display: inline-block; }
.badge.Revision { background-color: var(--primary-light); color: var(--primary-hover); }
body.dark-mode .badge.Revision { color: #818CF8; } /* Lighter indigo text for dark mode */
.badge.Homework { background-color: rgba(245, 158, 11, 0.1); color: var(--warning); }

.range-wrap { display: flex; align-items: center; gap: 12px; }
.range-val { font-weight: bold; color: var(--primary); background: var(--primary-light); padding: 4px 8px; border-radius: 6px; font-size: 0.85rem; min-width: 25px; text-align: center;}
body.dark-mode .range-val { color: #818CF8; }
.hidden { display: none; }
.action-row { display: flex; gap: 8px; }

.login-wrapper { display: flex; justify-content: center; align-items: center; height: 100vh; width: 100%; background-color: var(--bg-main); }
.login-card { width: 100%; max-width: 350px; }
.login-card button { width: 100%; margin-top: 15px; }