/* ============================================
   GROUP MAKER — Professional Educational Tool
   ============================================ */

/* Overlay */
.gm-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.55);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    z-index: 2147483639;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}
.gm-overlay.show {
    opacity: 1;
    pointer-events: all;
}

/* Main Container */
.gm-container {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0.92);
    width: 92vw;
    max-width: 1100px;
    height: 85vh;
    max-height: 760px;
    background: var(--bg-surface-solid, #1e293b);
    border: 1px solid var(--border-glass);
    border-radius: 20px;
    z-index: 2147483640;
    display: none;
    flex-direction: column;
    overflow: hidden;
    box-shadow: 0 25px 80px rgba(0,0,0,0.45), 0 0 0 1px rgba(255,255,255,0.06);
    font-family: 'Outfit', 'Inter', sans-serif;
    opacity: 0;
    transition: opacity 0.35s ease, transform 0.35s cubic-bezier(0.175,0.885,0.32,1.275);
}
.gm-container.show {
    display: flex;
    opacity: 1;
    transform: translate(-50%, -50%) scale(1);
}

/* Header */
.gm-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 24px;
    background: linear-gradient(135deg, rgba(99,102,241,0.12), rgba(168,85,247,0.08));
    border-bottom: 1px solid var(--border-glass);
    flex-shrink: 0;
}
.gm-header-left {
    display: flex;
    align-items: center;
    gap: 12px;
}
.gm-header-icon {
    width: 42px;
    height: 42px;
    border-radius: 12px;
    background: linear-gradient(135deg, #6366f1, #a855f7);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    color: #fff;
    box-shadow: 0 4px 12px rgba(99,102,241,0.35);
}
.gm-header-title {
    font-size: 20px;
    font-weight: 700;
    color: var(--text-main);
}
.gm-header-subtitle {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 1px;
}
.gm-header-actions {
    display: flex;
    align-items: center;
    gap: 8px;
}
.gm-btn {
    padding: 8px 18px;
    border: none;
    border-radius: 10px;
    font-family: inherit;
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: 6px;
}
.gm-btn:hover {
    transform: translateY(-1px);
}
.gm-btn-primary {
    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    color: #fff;
    box-shadow: 0 4px 12px rgba(99,102,241,0.3);
}
.gm-btn-primary:hover {
    box-shadow: 0 6px 20px rgba(99,102,241,0.45);
}
.gm-btn-success {
    background: linear-gradient(135deg, #10b981, #059669);
    color: #fff;
    box-shadow: 0 4px 12px rgba(16,185,129,0.3);
}
.gm-btn-success:hover {
    box-shadow: 0 6px 20px rgba(16,185,129,0.45);
}
.gm-btn-ghost {
    background: var(--bg-item);
    color: var(--text-main);
    border: 1px solid var(--border-glass);
}
.gm-btn-ghost:hover {
    background: var(--bg-item-hover);
}
.gm-btn-danger {
    background: linear-gradient(135deg, #ef4444, #dc2626);
    color: #fff;
    box-shadow: 0 4px 12px rgba(239,68,68,0.3);
}
.gm-btn-close {
    width: 34px;
    height: 34px;
    padding: 0;
    border-radius: 50%;
    background: rgba(255,255,255,0.06);
    border: 1px solid var(--border-glass);
    color: var(--text-muted);
    font-size: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.2s ease;
}
.gm-btn-close:hover {
    background: #fee2e2;
    color: #ef4444;
    transform: rotate(90deg);
}

/* Body Layout */
.gm-body {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* Left Sidebar — Student List */
.gm-sidebar {
    width: 280px;
    min-width: 280px;
    border-right: 1px solid var(--border-glass);
    display: flex;
    flex-direction: column;
    background: rgba(0,0,0,0.08);
}
.gm-sidebar-header {
    padding: 14px 16px;
    border-bottom: 1px solid var(--border-glass);
    display: flex;
    flex-direction: column;
    gap: 10px;
    flex-shrink: 0;
}
.gm-sidebar-title {
    font-size: 14px;
    font-weight: 700;
    color: var(--text-main);
    display: flex;
    align-items: center;
    gap: 8px;
}
.gm-sidebar-title .gm-count {
    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    color: #fff;
    font-size: 11px;
    padding: 2px 8px;
    border-radius: 20px;
    font-weight: 600;
}
.gm-search-row {
    display: flex;
    gap: 6px;
}
.gm-search-input {
    flex: 1;
    padding: 8px 12px;
    border-radius: 8px;
    border: 1px solid var(--border-glass);
    background: var(--bg-item);
    color: var(--text-main);
    font-family: inherit;
    font-size: 13px;
    outline: none;
    transition: border-color 0.2s;
}
.gm-search-input:focus {
    border-color: #6366f1;
}
.gm-add-btn {
    width: 36px;
    height: 36px;
    border-radius: 8px;
    border: none;
    background: linear-gradient(135deg, #10b981, #059669);
    color: #fff;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}
.gm-add-btn:hover {
    transform: scale(1.08);
    box-shadow: 0 4px 12px rgba(16,185,129,0.4);
}

/* Source Buttons */
.gm-source-row {
    display: flex;
    gap: 6px;
}
.gm-source-btn {
    flex: 1;
    padding: 6px 8px;
    border-radius: 8px;
    border: 1px solid var(--border-glass);
    background: var(--bg-item);
    color: var(--text-muted);
    font-family: inherit;
    font-size: 11px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 4px;
}
.gm-source-btn:hover {
    background: var(--bg-item-hover);
    color: var(--text-main);
}

/* Student List */
.gm-student-list {
    flex: 1;
    overflow-y: auto;
    padding: 8px;
    scrollbar-width: thin;
}
.gm-student-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 12px;
    border-radius: 10px;
    background: var(--bg-item);
    margin-bottom: 4px;
    cursor: grab;
    transition: all 0.2s;
    border: 1px solid transparent;
    user-select: none;
}
.gm-student-item:hover {
    background: var(--bg-item-hover);
    border-color: rgba(99,102,241,0.25);
}
.gm-student-item.dragging {
    opacity: 0.4;
    transform: scale(0.95);
}
.gm-student-avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    font-weight: 700;
    color: #fff;
    flex-shrink: 0;
}
.gm-student-name {
    flex: 1;
    font-size: 13px;
    font-weight: 500;
    color: var(--text-main);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.gm-student-remove {
    width: 24px;
    height: 24px;
    border-radius: 6px;
    border: none;
    background: transparent;
    color: var(--text-muted);
    font-size: 12px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: all 0.2s;
}
.gm-student-item:hover .gm-student-remove {
    opacity: 1;
}
.gm-student-remove:hover {
    background: #fee2e2;
    color: #ef4444;
}
.gm-student-empty {
    text-align: center;
    padding: 30px 16px;
    color: var(--text-muted);
    font-size: 13px;
}
.gm-student-empty i {
    font-size: 32px;
    margin-bottom: 10px;
    opacity: 0.3;
    display: block;
}

/* Right Content — Config + Groups */
.gm-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

/* Config Bar */
.gm-config {
    padding: 14px 20px;
    border-bottom: 1px solid var(--border-glass);
    display: flex;
    align-items: center;
    gap: 16px;
    flex-wrap: wrap;
    flex-shrink: 0;
    background: rgba(0,0,0,0.04);
}
.gm-config-group {
    display: flex;
    align-items: center;
    gap: 8px;
}
.gm-config-label {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    white-space: nowrap;
}
.gm-config-input {
    width: 64px;
    padding: 7px 10px;
    border-radius: 8px;
    border: 1px solid var(--border-glass);
    background: var(--bg-item);
    color: var(--text-main);
    font-family: inherit;
    font-size: 14px;
    font-weight: 600;
    text-align: center;
    outline: none;
    transition: border-color 0.2s;
}
.gm-config-input:focus {
    border-color: #6366f1;
}
.gm-config-sep {
    width: 1px;
    height: 28px;
    background: var(--border-glass);
}
.gm-generate-btn {
    padding: 10px 24px;
    border-radius: 10px;
    border: none;
    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    color: #fff;
    font-family: inherit;
    font-size: 14px;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.25s;
    box-shadow: 0 4px 15px rgba(99,102,241,0.35);
    display: flex;
    align-items: center;
    gap: 8px;
    letter-spacing: 0.3px;
}
.gm-generate-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(99,102,241,0.5);
}
.gm-generate-btn:active {
    transform: translateY(0);
}
.gm-generate-btn.generating {
    pointer-events: none;
    opacity: 0.7;
}

/* Groups Display Area */
.gm-groups-area {
    flex: 1;
    overflow-y: auto;
    padding: 16px 20px;
    scrollbar-width: thin;
}
.gm-groups-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 14px;
}
.gm-groups-empty {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    min-height: 300px;
    color: var(--text-muted);
    text-align: center;
    gap: 12px;
}
.gm-groups-empty i {
    font-size: 52px;
    opacity: 0.15;
}
.gm-groups-empty h3 {
    font-size: 18px;
    font-weight: 600;
    opacity: 0.6;
}
.gm-groups-empty p {
    font-size: 13px;
    opacity: 0.4;
    max-width: 300px;
}

/* Group Card */
.gm-group-card {
    background: var(--bg-item);
    border: 1px solid var(--border-glass);
    border-radius: 14px;
    overflow: hidden;
    transition: all 0.25s;
    animation: gmCardIn 0.4s cubic-bezier(0.175,0.885,0.32,1.275) both;
}
.gm-group-card:hover {
    border-color: rgba(99,102,241,0.3);
    box-shadow: 0 4px 20px rgba(0,0,0,0.15);
}
.gm-group-card.drag-over {
    border-color: #6366f1;
    box-shadow: 0 0 0 3px rgba(99,102,241,0.15);
    background: rgba(99,102,241,0.05);
}

@keyframes gmCardIn {
    from { opacity: 0; transform: translateY(20px) scale(0.95); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

.gm-group-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 14px;
    cursor: pointer;
}
.gm-group-header-left {
    display: flex;
    align-items: center;
    gap: 10px;
}
.gm-group-color {
    width: 8px;
    height: 32px;
    border-radius: 4px;
    flex-shrink: 0;
}
.gm-group-info h4 {
    font-size: 14px;
    font-weight: 700;
    color: var(--text-main);
    margin: 0;
}
.gm-group-info span {
    font-size: 11px;
    color: var(--text-muted);
}
.gm-group-actions {
    display: flex;
    gap: 4px;
}
.gm-group-action-btn {
    width: 28px;
    height: 28px;
    border-radius: 6px;
    border: none;
    background: transparent;
    color: var(--text-muted);
    font-size: 12px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
}
.gm-group-action-btn:hover {
    background: var(--bg-item-hover);
    color: var(--text-main);
}
.gm-group-action-btn.delete:hover {
    background: #fee2e2;
    color: #ef4444;
}

/* Group Members */
.gm-group-members {
    padding: 0 14px 12px;
    display: flex;
    flex-direction: column;
    gap: 4px;
    min-height: 40px;
}
.gm-group-member {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 6px 10px;
    border-radius: 8px;
    background: rgba(255,255,255,0.04);
    cursor: grab;
    transition: all 0.15s;
    border: 1px solid transparent;
}
.gm-group-member:hover {
    background: rgba(255,255,255,0.08);
}
.gm-group-member.dragging {
    opacity: 0.3;
}
.gm-member-avatar {
    width: 26px;
    height: 26px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    font-weight: 700;
    color: #fff;
    flex-shrink: 0;
}
.gm-member-name {
    flex: 1;
    font-size: 13px;
    color: var(--text-main);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.gm-member-remove {
    width: 22px;
    height: 22px;
    border-radius: 5px;
    border: none;
    background: transparent;
    color: var(--text-muted);
    font-size: 10px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: all 0.15s;
}
.gm-group-member:hover .gm-member-remove {
    opacity: 1;
}
.gm-member-remove:hover {
    background: #fee2e2;
    color: #ef4444;
}

/* Drop Zone Hint */
.gm-drop-hint {
    padding: 10px;
    border: 2px dashed var(--border-glass);
    border-radius: 8px;
    text-align: center;
    font-size: 12px;
    color: var(--text-muted);
    opacity: 0.5;
    transition: all 0.2s;
}
.gm-group-card.drag-over .gm-drop-hint {
    border-color: #6366f1;
    color: #6366f1;
    opacity: 1;
    background: rgba(99,102,241,0.05);
}

/* Saved Groups Footer */
.gm-footer {
    padding: 12px 20px;
    border-top: 1px solid var(--border-glass);
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-shrink: 0;
    background: rgba(0,0,0,0.04);
}
.gm-footer-left {
    display: flex;
    align-items: center;
    gap: 8px;
}
.gm-footer-right {
    display: flex;
    align-items: center;
    gap: 8px;
}
.gm-saved-select {
    padding: 7px 12px;
    border-radius: 8px;
    border: 1px solid var(--border-glass);
    background: var(--bg-item);
    color: var(--text-main);
    font-family: inherit;
    font-size: 13px;
    outline: none;
    min-width: 180px;
    cursor: pointer;
}
.gm-saved-select option {
    background: var(--bg-surface-solid);
    color: var(--text-main);
}

/* Shuffle Animation */
@keyframes gmShuffle {
    0%   { transform: translateX(0) rotate(0); }
    20%  { transform: translateX(-4px) rotate(-2deg); }
    40%  { transform: translateX(4px) rotate(2deg); }
    60%  { transform: translateX(-3px) rotate(-1deg); }
    80%  { transform: translateX(3px) rotate(1deg); }
    100% { transform: translateX(0) rotate(0); }
}
.gm-shuffling .gm-group-card {
    animation: gmShuffle 0.4s ease;
}

/* Responsive */
@media (max-width: 768px) {
    .gm-container {
        width: 98vw;
        height: 95vh;
        max-height: none;
        border-radius: 14px;
    }
    .gm-body {
        flex-direction: column;
    }
    .gm-sidebar {
        width: 100%;
        min-width: unset;
        max-height: 200px;
        border-right: none;
        border-bottom: 1px solid var(--border-glass);
    }
    .gm-groups-grid {
        grid-template-columns: 1fr;
    }
    .gm-config {
        flex-wrap: wrap;
        gap: 10px;
    }
    .gm-header-actions {
        gap: 4px;
    }
    .gm-btn {
        padding: 6px 12px;
        font-size: 12px;
    }
}