/* CSS Reset & Variables */
:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #64748b;
    --success-color: #22c55e;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-hover: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --border-color: #334155;
    --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
    --border-radius: 12px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background-color: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* Navigation */
nav {
    background-color: var(--surface);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    gap: 1.5rem;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: all 0.2s ease;
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-primary);
    background-color: var(--surface-hover);
}

/* Auth Section */
#auth-section {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 2rem;
}

.auth-container {
    background-color: var(--surface);
    padding: 2.5rem;
    border-radius: var(--border-radius);
    width: 100%;
    max-width: 400px;
    box-shadow: var(--card-shadow);
}

.auth-container h1 {
    text-align: center;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.tagline {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.auth-tabs {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.tab-btn {
    flex: 1;
    padding: 0.75rem;
    border: none;
    background-color: var(--surface-hover);
    color: var(--text-secondary);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.tab-btn.active {
    background-color: var(--primary-color);
    color: white;
}

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

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

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--background);
    color: var(--text-primary);
    font-size: 1rem;
    transition: border-color 0.2s ease;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s ease;
    font-weight: 500;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    width: 100%;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
}

.btn-secondary {
    background-color: var(--surface-hover);
    color: var(--text-primary);
}

.btn-secondary:hover {
    background-color: var(--secondary-color);
}

.btn-success {
    background-color: var(--success-color);
    color: white;
}

.btn-danger {
    background-color: var(--danger-color);
    color: white;
}

/* Messages */
.error-message {
    color: var(--danger-color);
    font-size: 0.9rem;
    margin-top: 1rem;
    text-align: center;
}

.success-message {
    color: var(--success-color);
    font-size: 0.9rem;
    margin-top: 1rem;
    text-align: center;
}

.warning-box {
    background-color: rgba(245, 158, 11, 0.1);
    border: 1px solid var(--warning-color);
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
}

.warning-box a {
    color: var(--warning-color);
}

/* Main Content */
main {
    padding: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.page {
    animation: fadeIn 0.3s ease;
}

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

.page h2 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

/* Cards Container */
.cards-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

/* User Card */
.user-card {
    background-color: var(--surface);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--card-shadow);
    transition: transform 0.2s ease;
}

.user-card:hover {
    transform: translateY(-4px);
}

.user-card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.user-card h3 {
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.user-card .username {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.match-score {
    background-color: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
}

.user-card .bio {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

.shared-interests {
    margin-bottom: 1rem;
}

.shared-interests h4 {
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin-bottom: 0.5rem;
}

.interest-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.interest-tag {
    background-color: var(--surface-hover);
    color: var(--text-primary);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
}

.interest-tag.must-have {
    background-color: rgba(99, 102, 241, 0.2);
    border: 1px solid var(--primary-color);
}

.interest-tag.shared {
    background-color: rgba(34, 197, 94, 0.15);
    border: 1px solid var(--success-color);
    color: var(--success-color);
}

.interest-tag.shared.must-have {
    background-color: rgba(34, 197, 94, 0.25);
    border: 1px solid var(--success-color);
    font-weight: 600;
}

.interest-tag.other {
    background-color: var(--surface-hover);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

.interest-tag.other.their-must-have {
    background-color: rgba(245, 158, 11, 0.15);
    border: 1px solid var(--warning-color);
    color: var(--warning-color);
}

.interest-tag.none {
    background-color: transparent;
    color: var(--text-secondary);
    font-style: italic;
}

.other-interests {
    margin-bottom: 1rem;
}

.other-interests h4 {
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin-bottom: 0.5rem;
}

.liked-you-badge {
    background-color: rgba(34, 197, 94, 0.2);
    color: var(--success-color);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
    margin-bottom: 1rem;
    display: inline-block;
}

.card-actions {
    display: flex;
    gap: 0.75rem;
}

.card-actions .btn {
    flex: 1;
    padding: 0.6rem;
}

/* Profile Section */
.profile-section {
    background-color: var(--surface);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    margin-bottom: 1.5rem;
}

.profile-section h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.hint {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

/* Interests Container */
.category-section {
    margin-bottom: 1.5rem;
}

.category-section h4 {
    color: var(--primary-color);
    margin-bottom: 0.75rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border-color);
}

.interests-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 0.75rem;
}

.interest-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem;
    background-color: var(--background);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.interest-item:hover {
    background-color: var(--surface-hover);
}

.interest-item input[type="checkbox"] {
    display: none;
}

.interest-item.selected {
    background-color: rgba(99, 102, 241, 0.2);
    border: 1px solid var(--primary-color);
}

.interest-item .interest-name {
    flex: 1;
    font-size: 0.9rem;
}

.weight-toggle {
    display: none;
    gap: 0.25rem;
}

.interest-item.selected .weight-toggle {
    display: flex;
}

.weight-btn {
    padding: 0.2rem 0.5rem;
    font-size: 0.75rem;
    border-radius: 4px;
    border: none;
    cursor: pointer;
    background-color: var(--surface-hover);
    color: var(--text-secondary);
}

.weight-btn.active {
    background-color: var(--primary-color);
    color: white;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 3rem;
    color: var(--text-secondary);
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.modal-content {
    background-color: var(--surface);
    padding: 2.5rem;
    border-radius: var(--border-radius);
    text-align: center;
    animation: scaleIn 0.3s ease;
}

@keyframes scaleIn {
    from { transform: scale(0.9); opacity: 0; }
    to { transform: scale(1); opacity: 1; }
}

.modal-content h2 {
    color: var(--success-color);
    margin-bottom: 1rem;
}

.modal-content p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

/* Unread Badge */
.unread-badge {
    background-color: var(--danger-color);
    color: white;
    font-size: 0.7rem;
    padding: 0.15rem 0.4rem;
    border-radius: 10px;
    margin-left: 0.25rem;
}

/* Chat Page */
.chat-container {
    display: flex;
    height: calc(100vh - 140px);
    background-color: var(--surface);
    border-radius: var(--border-radius);
    overflow: hidden;
}

.conversations-panel {
    width: 320px;
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}

.conversations-panel h3 {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    margin: 0;
}

#conversations-container {
    flex: 1;
    overflow-y: auto;
}

.conversation-item {
    display: flex;
    align-items: center;
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    cursor: pointer;
    transition: background-color 0.2s ease;
}

.conversation-item:hover {
    background-color: var(--surface-hover);
}

.conversation-item.active {
    background-color: var(--surface-hover);
    border-left: 3px solid var(--primary-color);
}

.conversation-avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background-color: var(--primary-color);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
    font-size: 1.2rem;
    margin-right: 1rem;
}

.conversation-info {
    flex: 1;
    min-width: 0;
}

.conversation-info h4 {
    margin: 0 0 0.25rem 0;
    font-size: 0.95rem;
    color: var(--text-primary);
}

.conversation-preview {
    color: var(--text-secondary);
    font-size: 0.85rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.conversation-meta {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 0.25rem;
}

.conversation-time {
    color: var(--text-secondary);
    font-size: 0.75rem;
}

.conversation-unread {
    background-color: var(--primary-color);
    color: white;
    font-size: 0.7rem;
    padding: 0.2rem 0.5rem;
    border-radius: 10px;
    min-width: 18px;
    text-align: center;
}

/* Chat Panel */
.chat-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.chat-empty-state {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
}

.chat-header {
    display: flex;
    align-items: center;
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    background-color: var(--surface);
}

.chat-header .btn-icon {
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    margin-right: 0.5rem;
    display: none;
}

.chat-header-info h3 {
    margin: 0;
    font-size: 1.1rem;
}

.messages-area {
    flex: 1;
    overflow-y: auto;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.message {
    max-width: 70%;
    padding: 0.75rem 1rem;
    border-radius: 16px;
    word-wrap: break-word;
}

.message.sent {
    align-self: flex-end;
    background-color: var(--primary-color);
    color: white;
    border-bottom-right-radius: 4px;
}

.message.received {
    align-self: flex-start;
    background-color: var(--surface-hover);
    color: var(--text-primary);
    border-bottom-left-radius: 4px;
}

.message-time {
    font-size: 0.7rem;
    opacity: 0.7;
    margin-top: 0.25rem;
}

.message.sent .message-time {
    text-align: right;
}

.message-input-area {
    display: flex;
    gap: 0.75rem;
    padding: 1rem;
    border-top: 1px solid var(--border-color);
    background-color: var(--surface);
}

.message-input-area input {
    flex: 1;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 24px;
    background-color: var(--background);
    color: var(--text-primary);
    font-size: 0.95rem;
}

.message-input-area input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.message-input-area .btn {
    border-radius: 24px;
    padding: 0.75rem 1.5rem;
}

/* Date separator in chat */
.message-date-separator {
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.8rem;
    padding: 0.5rem 0;
}

/* Utility Classes */
.hidden {
    display: none !important;
}

/* Responsive */
@media (max-width: 768px) {
    nav {
        flex-direction: column;
        gap: 1rem;
        padding: 1rem;
    }
    
    .nav-links {
        width: 100%;
        justify-content: center;
        flex-wrap: wrap;
    }
    
    main {
        padding: 1rem;
    }
    
    .cards-container {
        grid-template-columns: 1fr;
    }
    
    .interests-grid {
        grid-template-columns: 1fr;
    }
    
    /* Chat responsive */
    .chat-container {
        height: calc(100vh - 160px);
    }
    
    .conversations-panel {
        width: 100%;
        border-right: none;
    }
    
    .conversations-panel.hidden-mobile {
        display: none;
    }
    
    .chat-panel {
        display: none;
    }
    
    .chat-panel.active-mobile {
        display: flex;
        width: 100%;
    }
    
    .chat-header .btn-icon {
        display: block;
    }
    
    #no-chat-selected {
        display: none;
    }
    
    .message {
        max-width: 85%;
    }
}