:root {
    --primary-color: #2563EB;
    --primary-color-dark: #1D4ED8;
    --danger-color: #DC2626;
    --danger-color-dark: #B91C1C;
    --success-color: #16A34A;
    --light-bg-color: #F3F4F6;
    --white-color: #FFFFFF;
    
    --text-dark: #1F2937;
    --text-medium: #4B5563;
    --text-light: #6B7280;
    --text-white: #FFFFFF;
    --text-link: #2563EB;
    
    --border-color: #D1D5DB;
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);

    --spacing-1: 0.25rem;
    --spacing-2: 0.5rem;
    --spacing-3: 0.75rem;
    --spacing-4: 1rem;
    --spacing-6: 1.5rem;
    --spacing-8: 2rem;
    --spacing-12: 3rem;
    
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;

    --border-radius-md: 0.375rem;
    --border-radius-lg: 0.5rem;
    --border-radius-xl: 0.75rem;
    --border-radius-full: 9999px;
}

/* Global Styles & Reset */
*, *::before, *::after {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--light-bg-color);
    color: var(--text-dark);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Layout */
.app-wrapper {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

.app-container {
    flex-grow: 1;
    overflow-y: auto;
    padding: var(--spacing-4);
    -webkit-overflow-scrolling: touch;
}

.container {
    max-width: 1280px;
    margin-left: auto;
    margin-right: auto;
    padding-left: var(--spacing-4);
    padding-right: var(--spacing-4);
}

.page-container {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-12) var(--spacing-4);
}

/* Page transition animation */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.3s ease-in-out;
}

/* Card Component */
.card {
    background-color: var(--white-color);
    box-shadow: var(--shadow-md);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-8);
}

/* Form Components */
.form-wrapper {
    max-width: 42rem; /* md */
    width: 100%;
}
.form-wrapper > *:not([hidden]) ~ *:not([hidden]) {
    margin-top: var(--spacing-8);
}
.form-space-y-6 > *:not([hidden]) ~ *:not([hidden]) {
     margin-top: var(--spacing-6);
}
.form-space-y-4 > *:not([hidden]) ~ *:not([hidden]) {
     margin-top: var(--spacing-4);
}
.form-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-4);
}
.form-label {
    display: block;
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--text-medium);
    margin-bottom: var(--spacing-1);
}
.form-input, .form-select {
    display: block;
    width: 100%;
    padding: var(--spacing-2) var(--spacing-3);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-md);
    box-shadow: var(--shadow-sm);
    font-size: var(--font-size-sm);
}
.form-input:focus, .form-select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.5);
}

/* Button Component */
.btn {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    padding: var(--spacing-2) var(--spacing-4);
    border: 1px solid transparent;
    border-radius: var(--border-radius-md);
    box-shadow: var(--shadow-sm);
    font-size: var(--font-size-sm);
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s;
}
.btn:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.5);
}
.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}
.btn-primary {
    background-color: var(--primary-color);
    color: var(--text-white);
}
.btn-primary:hover {
    background-color: var(--primary-color-dark);
}
.btn-danger {
    background-color: var(--danger-color);
    color: var(--text-white);
}
.btn-danger:hover {
    background-color: var(--danger-color-dark);
}
.btn .spinner {
    animation: spin 1s linear infinite;
    width: 20px;
    height: 20px;
    margin-right: 0.75rem;
    margin-left: -0.25rem;
}
@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

/* Header */
.main-header {
    background-color: var(--primary-color);
    color: var(--text-white);
    box-shadow: var(--shadow-md);
    width: 100%;
}
.main-header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 4rem; /* 64px */
}
.main-header h1 {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin: 0;
}
.main-header p {
    font-size: var(--font-size-xs);
    color: #A5B4FC; /* blue-200 */
    margin: 0;
}

/* Bottom Navigation */
.bottom-nav {
    background-color: var(--white-color);
    box-shadow: var(--shadow-md);
    width: 100%;
    border-top: 1px solid #E5E7EB;
    display: flex;
}
.nav-item {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 100%;
    padding-top: var(--spacing-2);
    padding-bottom: var(--spacing-1);
    transition: color 0.2s;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-light);
}
.nav-item:hover {
    color: var(--primary-color);
}
.nav-item.active {
    color: var(--primary-color);
}
.nav-item .label {
    font-size: var(--font-size-xs);
    margin-top: var(--spacing-1);
}
.notification-dot {
    position: absolute;
    top: var(--spacing-1);
    right: 50%;
    transform: translateX(1rem);
    width: 0.5rem;
    height: 0.5rem;
    background-color: var(--danger-color);
    border-radius: var(--border-radius-full);
}

/* Typography Helpers */
.text-center { text-align: center; }
.text-link {
    font-weight: 500;
    color: var(--text-link);
    background: none;
    border: none;
    padding: 0;
    cursor: pointer;
}
.text-link:hover { text-decoration: underline; }
.text-danger { color: var(--danger-color); }
.text-success { color: var(--success-color); }
.text-lg { font-size: var(--font-size-lg); }
.text-xl { font-size: var(--font-size-xl); }
.text-2xl { font-size: var(--font-size-2xl); }
.text-3xl { font-size: var(--font-size-3xl); }
.font-bold { font-weight: 700; }
.font-semibold { font-weight: 600; }
.mb-4 { margin-bottom: var(--spacing-4); }
.mb-6 { margin-bottom: var(--spacing-6); }
.mt-4 { margin-top: var(--spacing-4); }
.mt-8 { margin-top: var(--spacing-8); }
.mt-10 { margin-top: var(--spacing-10); }

/* Dashboard */
.dashboard-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-6);
}
.dashboard-card {
    background-color: var(--white-color);
    box-shadow: var(--shadow-md);
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    transition: box-shadow 0.3s;
    cursor: pointer;
}
.dashboard-card:hover {
    box-shadow: var(--shadow-lg);
}
.dashboard-card-content {
    padding: var(--spacing-6);
}
.dashboard-card h3 {
    margin: 0;
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--text-dark);
}
.dashboard-card p {
    margin: var(--spacing-2) 0 0;
    color: var(--text-light);
}
.dashboard-card .card-link {
    margin-top: var(--spacing-4);
    color: var(--primary-color);
    font-weight: 600;
    display: flex;
    align-items: center;
}
.dashboard-card .card-link svg {
    margin-left: var(--spacing-2);
}

/* Profile / Member Card */
.member-card {
    padding: var(--spacing-6);
    background: linear-gradient(to bottom right, #1E40AF, #1E3A8A); /* from-blue-700 to-blue-900 */
    color: var(--text-white);
    border-radius: var(--border-radius-xl);
    box-shadow: var(--shadow-xl);
    max-width: 28rem;
    margin: 0 auto;
    aspect-ratio: 85.6 / 53.98;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}
.member-card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
}
.member-card-header h2 {
    font-size: 1.3rem; /* custom size */
    font-weight: 700;
    letter-spacing: 0.05em;
    margin: 0;
}
.member-card-brand {
    text-align: right;
}
.member-card-brand p { margin: 0; }
.member-card-brand .brand-name {
    font-weight: 600;
    font-size: var(--font-size-lg);
}
.member-card-brand .brand-subtitle {
    font-size: var(--font-size-xs);
}

.member-card-body {
    display: flex;
    align-items: center;
    margin-top: var(--spacing-4);
    gap: var(--spacing-4);
}
.avatar-container {
    position: relative;
    cursor: pointer;
}
.avatar-container .avatar-img {
    width: 6rem; /* w-24 */
    height: 6rem; /* h-24 */
    border-radius: var(--border-radius-md);
    border: 2px solid #60A5FA; /* border-blue-300 */
    object-fit: cover;
}
.avatar-overlay {
    position: absolute;
    inset: 0;
    background-color: rgba(0,0,0,0);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.2s;
    border-radius: var(--border-radius-md);
}
.avatar-container:hover .avatar-overlay {
    background-color: rgba(0,0,0,0.5);
}
.avatar-overlay svg {
    opacity: 0;
    transition: opacity 0.2s;
}
.avatar-container:hover .avatar-overlay svg {
    opacity: 1;
}

.member-card-details {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: var(--spacing-1) var(--spacing-4);
    font-size: var(--font-size-sm);
}
.member-card-details .label {
    font-weight: 300;
    color: #BFDBFE; /* blue-200 */
}
.member-card-details .value {
    font-weight: 600;
}
.member-card-details .mono {
    font-family: monospace;
}
.member-card-footer {
    margin-top: auto;
    text-align: right;
    font-size: var(--font-size-xs);
    padding-top: var(--spacing-4);
}
.status-badge {
    font-weight: 700;
    background-color: var(--success-color);
    color: var(--text-white);
    padding: var(--spacing-1) var(--spacing-2);
    border-radius: var(--border-radius-full);
}
.profile-details-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-4);
    color: var(--text-medium);
}

/* Chat */
.chat-page-container {
    height: 100%;
    display: flex;
    flex-direction: column;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    border: 1px solid var(--border-color);
    background-color: var(--white-color);
}
.chat-layout {
    display: flex;
    flex-direction: column;
    height: 100%;
}
.member-list-panel {
    width: 100%;
    background-color: var(--white-color);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}
.member-list-header {
    padding: var(--spacing-3);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    background-color: var(--white-color);
    z-index: 10;
}
.member-list-header h2 {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin: 0 0 var(--spacing-2) 0;
}
.member-list {
    overflow-y: auto;
    flex-grow: 1;
    list-style: none;
    padding: 0;
    margin: 0;
}
.member-group-header {
    width: 100%;
    text-align: left;
    padding: var(--spacing-3);
    background-color: #F9FAFB; /* gray-50 */
    font-weight: 600;
    color: var(--text-medium);
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    border: none;
    transition: background-color 0.2s;
}
.member-group-header:hover {
    background-color: #F3F4F6; /* gray-200 */
}
.member-group-header svg {
    transition: transform 0.2s;
}
.member-group-header.expanded svg {
    transform: rotate(90deg);
}
.member-sublist {
    list-style: none;
    padding: 0;
    margin: 0;
}
.member-sublist.hidden {
    display: none;
}
.member-list-item {
    display: flex;
    align-items: center;
    padding: var(--spacing-4);
    cursor: pointer;
    border-bottom: 1px solid #E5E7EB; /* gray-200 */
}
.member-list-item:hover {
    background-color: #F9FAFB; /* gray-100 */
}
.member-list-item.active {
    background-color: #DBEAFE; /* blue-100 */
}
.member-list-item img {
    width: 3rem;
    height: 3rem;
    border-radius: var(--border-radius-full);
    margin-right: var(--spacing-4);
    object-fit: cover;
}
.member-list-item .name {
    font-weight: 600;
    color: var(--text-dark);
}
.member-list-item .detail {
    font-size: var(--font-size-sm);
    color: var(--text-light);
}
.chat-area {
    flex: 1;
    display: flex;
    flex-direction: column;
}
.chat-placeholder {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #F9FAFB; /* gray-50 */
    text-align: center;
    color: var(--text-light);
}
.chat-window {
    flex: 1;
    display: flex;
    flex-direction: column;
}
.chat-header {
    padding: var(--spacing-4);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    background-color: var(--white-color);
    cursor: pointer;
    transition: background-color 0.2s;
}
.chat-header:hover {
    background-color: #F9FAFB;
}
.chat-header img {
    width: 2.5rem;
    height: 2.5rem;
    border-radius: var(--border-radius-full);
    margin-right: var(--spacing-3);
    object-fit: cover;
}
.chat-header h3 {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--text-dark);
    margin: 0;
}
.message-list {
    flex: 1;
    padding: var(--spacing-4);
    overflow-y: auto;
    background-color: #F9FAFB; /* gray-50 */
}
.message-bubble-container {
    display: flex;
    margin-bottom: var(--spacing-4);
}
.message-bubble-container.current-user {
    justify-content: flex-end;
}
.message-bubble {
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-2) var(--spacing-4);
    max-width: 75%;
}
.message-bubble.current-user {
    background-color: var(--primary-color);
    color: var(--text-white);
}
.message-bubble.other-user {
    background-color: var(--white-color);
    color: var(--text-dark);
    box-shadow: var(--shadow-sm);
}
.message-bubble .timestamp {
    font-size: var(--font-size-xs);
    margin-top: var(--spacing-1);
}
.message-bubble.current-user .timestamp {
    color: #BFDBFE; /* blue-200 */
}
.message-bubble.other-user .timestamp {
    color: #9CA3AF; /* gray-400 */
}
.message-form-container {
    padding: var(--spacing-4);
    background-color: var(--white-color);
    border-top: 1px solid var(--border-color);
}
.message-form {
    display: flex;
}
.message-form input {
    flex: 1;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-full) 0 0 var(--border-radius-full);
    padding: var(--spacing-2) var(--spacing-4);
}
.message-form input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.5);
}
.message-form button {
    background-color: var(--primary-color);
    color: var(--text-white);
    padding: var(--spacing-2) var(--spacing-6);
    border: none;
    border-radius: 0 var(--border-radius-full) var(--border-radius-full) 0;
    cursor: pointer;
    transition: background-color 0.2s;
}
.message-form button:hover {
    background-color: var(--primary-color-dark);
}

/* Responsive Design */
@media (min-width: 640px) {
    .app-container {
        padding: var(--spacing-6);
    }
    .profile-details-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (min-width: 768px) {
    .form-grid {
        grid-template-columns: 1fr 1fr;
    }
    .dashboard-grid {
        grid-template-columns: 1fr 1fr;
    }
    .chat-layout {
        flex-direction: row;
    }
    .member-list-panel {
        width: 33.333333%;
    }
}

@media (min-width: 1024px) {
    .app-container {
        padding: var(--spacing-8);
    }
    .dashboard-grid {
        grid-template-columns: 1fr 1fr 1fr;
    }
    .member-list-panel {
        width: 25%;
    }
}