/* ==========================================================================
   2. UI Components: Auth, Navbar, Drawer, Buttons, Modals & Mobile Tab Bar
   ========================================================================== */

/* Auth Screen / Login Overlay */
.auth-screen,
.login-overlay {
    position: fixed;
    inset: 0;
    z-index: 10000;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background-color: var(--bg-main);
    background-image: radial-gradient(circle at top, rgba(56, 189, 248, 0.15), transparent 70%);
}

.auth-card,
.login-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 36px 32px;
    width: 100%;
    max-width: 420px;
    box-shadow: var(--shadow-lg);
    animation: fadeInScale 0.2s ease-out;
}

@keyframes fadeInScale {
    from {
        opacity: 0;
        transform: scale(0.96);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes slideUpSheet {
    from {
        transform: translateY(100%);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.auth-header,
.login-header {
    text-align: center;
    margin-bottom: 28px;
}

.auth-header .app-logo,
.login-header .login-logo {
    font-size: 48px;
    margin-bottom: 8px;
    display: block;
}

.auth-header h2,
.login-header h1 {
    font-size: 24px;
    font-weight: 700;
    color: var(--text-main);
}

.auth-header p,
.login-header p {
    color: var(--text-muted);
    font-size: 14px;
    margin-top: 4px;
}

.login-form {
    display: flex;
    flex-direction: column;
}

.login-error {
    background-color: var(--danger-dim);
    color: var(--danger);
    border: 1px solid var(--danger);
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    margin-bottom: 16px;
    text-align: center;
}

.auth-footer,
.login-footer {
    margin-top: 24px;
    text-align: center;
    font-size: 12px;
    color: var(--text-dim);
}

.form-group {
    margin-bottom: 18px;
}

.form-group label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 6px;
}

.form-group input {
    width: 100%;
    padding: 12px 14px;
    background-color: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-main);
    font-size: 15px;
    outline: none;
    transition: var(--transition);
}

.form-group input:focus {
    border-color: var(--border-focus);
    box-shadow: 0 0 0 3px var(--primary-dim);
}

.error-banner {
    background-color: var(--danger-dim);
    border: 1px solid var(--danger);
    color: #fca5a5;
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    margin-bottom: 16px;
}

.success-banner {
    background-color: var(--success-dim, rgba(16, 185, 129, 0.15));
    border: 1px solid var(--success, #10b981);
    color: #86efac;
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    margin-bottom: 16px;
}


/* App Navbar */
.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* App Navbar (Unified Layout) */
.navbar {
    background-color: var(--bg-surface);
    border-bottom: 1px solid var(--border-color);
    padding: 8px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    position: sticky;
    top: 0;
    z-index: 100;
    min-height: var(--navbar-height);
    box-sizing: border-box;
}

.nav-left {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-shrink: 0;
}

.drawer-toggle-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border-radius: var(--radius-sm);
    background-color: transparent;
    border: 1px solid transparent;
    color: var(--text-main);
    cursor: pointer;
    font-size: 20px;
    line-height: 1;
    transition: var(--transition);
}

.drawer-toggle-btn:hover {
    background-color: var(--bg-surface-hover);
    border-color: var(--border-color);
    color: var(--primary);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    user-select: none;
    transition: opacity 0.15s ease;
}

.nav-brand:hover {
    opacity: 0.85;
}

.brand-icon {
    font-size: 24px;
}

.brand-title {
    font-size: 20px;
    font-weight: 800;
    color: var(--text-main);
    letter-spacing: -0.5px;
}

.brand-sub {
    font-size: 12px;
    background-color: var(--primary-dim);
    color: var(--primary);
    padding: 2px 8px;
    border-radius: var(--radius-full);
    font-weight: 600;
    margin-left: 4px;
}

.nav-center {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 14px;
    flex: 1;
    min-width: 0;
}

.nav-stats {
    display: flex;
    gap: 8px;
}

.stat-badge {
    font-size: 13px;
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    padding: 4px 12px;
    border-radius: var(--radius-full);
    color: var(--text-muted);
}

.stat-badge strong {
    color: var(--text-main);
}

.stat-badge.stat-today strong {
    color: var(--success);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-shrink: 0;
}

.user-profile-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 5px 12px;
    border-radius: var(--radius-full);
    background-color: var(--bg-surface-hover);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.user-profile-btn:hover {
    border-color: var(--primary);
    color: var(--primary);
    background-color: var(--primary-dim);
}

.user-avatar-icon {
    font-size: 15px;
}

.user-badge {
    font-size: 13px;
    color: var(--text-main);
    font-weight: 600;
}

/* -----------------------------------------------------------------------
   Unified Navigation Drawer (Desktop & Mobile)
   ----------------------------------------------------------------------- */
.drawer-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: rgba(0, 0, 0, 0.65);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: 1999;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.26s cubic-bezier(0.16, 1, 0.3, 1);
}

.drawer-backdrop.active {
    opacity: 1;
    pointer-events: auto;
}

.app-drawer {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: min(340px, 86vw);
    background-color: var(--bg-surface);
    border-right: 1px solid var(--border-color);
    box-shadow: 4px 0 28px rgba(0, 0, 0, 0.5);
    z-index: 2000;
    display: flex;
    flex-direction: column;
    transform: translateX(-100%);
    transition: transform 0.28s cubic-bezier(0.16, 1, 0.3, 1);
    will-change: transform;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
}

.app-drawer.active {
    transform: translateX(0);
}

body.drawer-open {
    overflow: hidden !important;
}

.drawer-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: calc(16px + env(safe-area-inset-top, 0px)) 16px 14px 18px;
    border-bottom: 1px solid var(--border-color);
    background-color: var(--bg-surface);
    position: sticky;
    top: 0;
    z-index: 10;
}

.drawer-user-card {
    display: flex;
    align-items: center;
    gap: 12px;
    min-width: 0;
}

.drawer-user-avatar {
    width: 42px;
    height: 42px;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, var(--primary), #6366f1);
    color: #ffffff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    flex-shrink: 0;
    box-shadow: var(--shadow-sm);
}

.drawer-user-info {
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.drawer-user-name {
    font-size: 15px;
    font-weight: 700;
    color: var(--text-main);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.drawer-user-desc {
    font-size: 12px;
    color: var(--text-muted);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.drawer-close-btn {
    width: 34px;
    height: 34px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    color: var(--text-muted);
    background: transparent;
    border: none;
    cursor: pointer;
    transition: var(--transition);
}

.drawer-close-btn:hover {
    background-color: var(--bg-surface-hover);
    color: var(--text-main);
}

.drawer-stats-summary {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 8px;
    padding: 12px 14px;
    margin: 12px 14px 4px 14px;
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    text-align: center;
}

.drawer-stat-item {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.drawer-stat-val {
    font-size: 16px;
    font-weight: 800;
    color: var(--text-main);
}

.drawer-stat-lbl {
    font-size: 10px;
    font-weight: 600;
    color: var(--text-dim);
    text-transform: uppercase;
    letter-spacing: 0.3px;
}

.drawer-nav {
    flex: 1;
    padding: 8px 12px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.drawer-section-title {
    font-size: 11px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.6px;
    color: var(--text-dim);
    padding: 12px 8px 4px 8px;
}

.drawer-nav-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 3px;
}

.drawer-nav-item {
    width: 100%;
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 12px;
    border-radius: var(--radius-sm);
    background: transparent;
    border: 1px solid transparent;
    color: var(--text-main);
    font-size: 14px;
    font-weight: 500;
    text-align: left;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
}

.drawer-nav-item:hover {
    background-color: var(--bg-surface-hover);
    color: var(--primary);
    border-color: var(--border-color);
}

.drawer-nav-item.active {
    background-color: var(--primary-dim);
    color: var(--primary);
    border-color: rgba(56, 189, 248, 0.3);
    font-weight: 700;
}

.drawer-item-icon {
    font-size: 18px;
    width: 24px;
    text-align: center;
    flex-shrink: 0;
}

.drawer-item-label {
    flex: 1;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.drawer-badge {
    padding: 2px 7px;
    font-size: 11px;
    font-weight: 700;
    border-radius: var(--radius-full);
    background-color: var(--primary);
    color: #0f172a;
    line-height: 1.2;
}

.drawer-footer {
    padding: 14px 16px calc(14px + env(safe-area-inset-bottom, 0px)) 16px;
    border-top: 1px solid var(--border-color);
    font-size: 12px;
    color: var(--text-dim);
    text-align: center;
}


/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 10px 18px;
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    border: none;
    transition: var(--transition);
}

.btn-primary {
    background-color: var(--primary);
    color: #0f172a;
}

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

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

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

.btn-outline {
    background-color: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-muted);
}

.btn-outline:hover {
    border-color: var(--text-main);
    color: var(--text-main);
}

.btn-sm {
    padding: 6px 12px;
    font-size: 12px;
}

.btn-lg {
    padding: 14px 24px;
    font-size: 16px;
}

.btn-block {
    width: 100%;
}

.btn-subtext {
    font-size: 11px;
    opacity: 0.8;
    margin-left: 4px;
}

.icon-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 6px 10px;
    cursor: pointer;
    color: var(--text-muted);
    font-size: 16px;
    transition: var(--transition);
}

.icon-btn:hover {
    color: var(--text-main);
    border-color: var(--text-main);
}


/* Spinner */
.lookup-spinner {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    padding: 24px;
    color: var(--primary);
    font-size: 14px;
    font-weight: 500;
}

.spinner {
    width: 24px;
    height: 24px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}


/* Modal */
.modal-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 20px;
}

.modal-window {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    width: 100%;
    max-width: 520px;
    box-shadow: var(--shadow-lg);
    display: flex;
    flex-direction: column;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 18px;
    font-weight: 700;
}

.modal-body {
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    padding: 14px 20px;
    border-top: 1px solid var(--border-color);
}

.modal-sm {
    max-width: 420px;
}

/* Navigation Additions */
.nav-center {
    display: flex;
    align-items: center;
}

.btn-trainer {
    background: linear-gradient(135deg, #0284c7, #38bdf8);
    color: #0f172a;
    font-weight: 700;
    box-shadow: 0 2px 10px rgba(56, 189, 248, 0.25);
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 7px 14px;
    border-radius: var(--radius-sm);
    border: none;
    cursor: pointer;
    transition: var(--transition);
}

.btn-trainer:hover {
    box-shadow: 0 4px 14px rgba(56, 189, 248, 0.45);
    transform: translateY(-1px);
}

.srs-due-badge {
    background-color: #0f172a;
    color: #38bdf8;
    font-size: 11px;
    font-weight: 800;
    padding: 1px 7px;
    border-radius: var(--radius-full);
    min-width: 18px;
    text-align: center;
}

.srs-due-badge.has-due {
    background-color: #ef4444;
    color: #ffffff;
    animation: pulseDue 2s infinite;
}

@keyframes pulseDue {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.15); }
}


/* Export Modal */
.export-modal-window {
    max-width: 620px;
}

.modal-lead {
    font-size: 14px;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.export-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.export-tile {
    background-color: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    gap: 12px;
    transition: var(--transition);
}

.export-tile:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.export-tile-icon {
    font-size: 28px;
}

.export-tile-info h4 {
    font-size: 15px;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 4px;
}

.export-tile-info p {
    font-size: 12px;
    color: var(--text-dim);
    line-height: 1.4;
}


/* Voice Settings Modal */
.voice-modal-window {
    max-width: 680px;
    width: 95%;
}

.voice-modal-body {
    padding: 20px 24px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    max-height: 80vh;
    overflow-y: auto;
}

.modal-desc-sub {
    font-size: 13px;
    color: var(--text-muted);
    margin: 0 0 10px 0;
}

.voice-group-title {
    font-size: 14px;
    font-weight: 700;
    color: var(--text-main);
    display: block;
    margin-bottom: 10px;
}

.voice-options-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
}

@media (max-width: 680px) {
    .voice-options-grid {
        grid-template-columns: 1fr;
    }
}

.voice-card-label {
    cursor: pointer;
    display: block;
    position: relative;
    user-select: none;
}

.voice-card-label input[type="radio"] {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.voice-card {
    border: 1px solid var(--border-color);
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 14px 14px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    height: 100%;
    transition: var(--transition);
}

.voice-card:hover {
    border-color: var(--primary-dim);
}

.voice-card-label input[type="radio"]:checked + .voice-card {
    border-color: var(--primary);
    background: var(--bg-main);
    box-shadow: 0 0 0 2px var(--primary-dim);
}

.voice-card-head {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 6px;
}

.voice-card-desc {
    font-size: 12px;
    line-height: 1.4;
    color: var(--text-muted);
    flex: 1;
}

.badge-recommended {
    background: rgba(16, 185, 129, 0.15);
    color: #10b981;
    font-size: 10px;
    font-weight: 700;
    padding: 2px 6px;
    border-radius: 4px;
    white-space: nowrap;
}

.badge-uk {
    background: rgba(59, 130, 246, 0.15);
    color: #3b82f6;
    font-size: 10px;
    font-weight: 700;
    padding: 2px 6px;
    border-radius: 4px;
    white-space: nowrap;
}

.voice-test-btn {
    align-self: flex-start;
    margin-top: 4px;
}


/* Mobile Navigation & Tab Bar (iOS Native Style Base) */
.mobile-only-btn,
.mobile-tab-bar,
.mobile-only {
    display: none;
}

.mobile-tab-bar {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: calc(56px + env(safe-area-inset-bottom, 0px));
    padding-bottom: env(safe-area-inset-bottom, 0px);
    background-color: rgba(30, 41, 59, 0.94);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-top: 1px solid var(--border-color);
    z-index: 1000;
    align-items: center;
    justify-content: space-around;
}

[data-theme="light"] .mobile-tab-bar {
    background-color: rgba(255, 255, 255, 0.94);
}

.tab-item {
    flex: 1;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 3px;
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    position: relative;
    padding: 6px 0;
    -webkit-tap-highlight-color: transparent;
    transition: var(--transition);
}

.tab-item:active {
    transform: scale(0.92);
}

.tab-item.active {
    color: var(--primary);
}

.tab-icon {
    font-size: 19px;
    line-height: 1;
}

.tab-label {
    font-size: 10px;
    font-weight: 600;
    letter-spacing: -0.2px;
}

.tab-badge {
    position: absolute;
    top: 5px;
    right: calc(50% - 18px);
    background-color: #ef4444;
    color: #ffffff;
    font-size: 10px;
    font-weight: 700;
    padding: 1px 5px;
    border-radius: 9999px;
    line-height: 1.2;
}

/* Mobile Sheet / Menu */
.mobile-sheet-window {
    max-width: 440px;
}

.mobile-user-card {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 16px;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    margin-bottom: 16px;
}

.mobile-user-avatar {
    font-size: 28px;
    background: var(--bg-surface-hover);
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-full);
}

.mobile-user-info strong {
    font-size: 16px;
    color: var(--text-main);
}

.mobile-user-info .subtitle {
    font-size: 12px;
    color: var(--text-muted);
}

.mobile-menu-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

/* Sheet drag handle for mobile bottom sheets */
.sheet-drag-handle {
    width: 38px;
    height: 4px;
    border-radius: 2px;
    background-color: var(--border-color);
    margin: 0 auto 10px auto;
}


/* --- Responsive Mobile Overrides (max-width: 768px) --- */
@media (max-width: 768px) {
    /* 3. Header & Navigation: Unified Responsive Header */
    .navbar {
        padding: calc(8px + env(safe-area-inset-top, 0px)) 10px 8px 10px;
        gap: 8px;
    }

    .brand-sub,
    .nav-stats {
        display: none !important;
    }

    .btn-trainer .trainer-text {
        display: none !important;
    }

    .btn-trainer {
        padding: 6px 10px !important;
        font-size: 13px !important;
        min-height: 36px;
    }

    .user-profile-btn #user-display-name {
        display: none !important;
    }

    .user-profile-btn {
        padding: 6px 10px !important;
        border-radius: var(--radius-sm);
        min-height: 36px;
    }

    .mobile-tab-bar {
        display: flex !important;
    }

    .mobile-only {
        display: block !important;
    }

    /* 8. Modals: Mobile Bottom-Sheet style */
    .modal-backdrop {
        padding: 0;
        align-items: flex-end;
    }

    .modal-window {
        max-width: 100%;
        max-height: calc(90dvh - env(safe-area-inset-top, 0px));
        border-radius: 20px 20px 0 0;
        border-bottom: none;
        overflow-y: auto;
        -webkit-overflow-scrolling: touch;
        padding-bottom: env(safe-area-inset-bottom, 0px);
        animation: slideUpSheet 0.22s cubic-bezier(0.16, 1, 0.3, 1);
    }

    .stats-modal-window {
        width: 100%;
        max-width: 100%;
    }

    .stats-hero-grid {
        grid-template-columns: 1fr 1fr;
        gap: 8px;
    }

    .heatmap-container-wrap {
        -webkit-overflow-scrolling: touch;
    }

    /* 9. Batch action bar */
    .batch-action-bar {
        flex-direction: column;
        gap: 10px;
        bottom: calc(64px + env(safe-area-inset-bottom, 0px)) !important;
        left: 10px;
        right: 10px;
    }

    .batch-actions {
        width: 100%;
        justify-content: space-between;
    }

}