/* Linear Icons CSS */
.linear-icon {
    display: inline-block;
    width: 1em;
    height: 1em;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* App Icon - Lightning Bolt */
.app-icon {
    display: inline-block;
    width: 4rem;
    height: 4rem;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.app-icon svg {
    width: 100%;
    height: 100%;
}

/* Auth Icons */
.auth-icon {
    display: inline-block;
    width: 1.25rem;
    height: 1.25rem;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* Action Icons */
.action-icon {
    display: inline-block;
    width: 2.5rem;
    height: 2.5rem;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* Navigation Icons */
.nav-icon {
    display: inline-block;
    width: 1.2rem;
    height: 1.2rem;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* Activity Icons */
.activity-icon {
    display: inline-block;
    width: 1.5rem;
    height: 1.5rem;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* Subject Icons */
.subject-icon {
    display: inline-block;
    width: 2rem;
    height: 2rem;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.subject-icon-large {
    display: inline-block;
    width: 3rem;
    height: 3rem;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* Content Icons */
.content-icon {
    display: inline-block;
    width: 1.2rem;
    height: 1.2rem;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* Empty State Icons */
.empty-icon {
    display: inline-block;
    width: 4rem;
    height: 4rem;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* Icon Button */
.icon-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    border: none;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition-smooth);
    border: 1px solid rgba(74, 222, 128, 0.2);
}

.icon-btn:hover {
    background: var(--bg-tertiary);
    transform: scale(1.05);
    box-shadow: var(--shadow-neon);
    border-color: var(--neon-green);
}

/* Theme Icon */
#theme-icon {
    display: inline-block;
    width: 1.2rem;
    height: 1.2rem;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* Profile Avatar */
#profile-avatar {
    display: inline-block;
    width: 3rem;
    height: 3rem;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .action-icon {
        width: 2rem;
        height: 2rem;
    }
    
    .nav-icon {
        width: 1.1rem;
        height: 1.1rem;
    }
    
    .icon-btn {
        width: 40px;
        height: 40px;
    }
    
    .subject-icon-large {
        width: 2rem;
        height: 2rem;
    }
    
    .content-icon {
        width: 1rem;
        height: 1rem;
    }
}