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

:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --bg: #f8fafc;
    --sidebar-bg: #1e293b;
    --sidebar-text: #e2e8f0;
    --card-bg: #ffffff;
    --text: #1e293b;
    --text-light: #64748b;
    --border: #e2e8f0;
    --user-msg: #dbeafe;
    --assistant-msg: #f1f5f9;
    --error: #ef4444;
    --success: #22c55e;
    --radius: 12px;
    --primary-light: #dbeafe;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
    --shadow-lg: 0 8px 30px rgba(0,0,0,0.15);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

/* Auth page */
.auth-page {
    background: linear-gradient(135deg, #1e293b 0%, #334155 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.auth-container {
    width: 100%;
    max-width: 440px;
    padding: 20px;
}

.auth-card {
    background: var(--card-bg);
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    padding: 40px 32px 32px;
}

.auth-header {
    text-align: center;
    margin-bottom: 24px;
}

.auth-logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 8px;
}

.logo-accent {
    width: 6px;
    height: 36px;
    border-radius: 3px;
    background: linear-gradient(180deg, #dc2626, #fff, #dc2626);
}

.auth-logo h1 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text);
}

.subtitle {
    color: var(--text-light);
    font-size: 0.95rem;
}

.auth-features {
    display: flex;
    flex-direction: column;
    gap: 10px;
    padding: 16px;
    background: var(--bg);
    border-radius: 12px;
    margin-bottom: 24px;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.9rem;
    color: var(--text);
}

.feature-icon {
    font-size: 1.1rem;
    width: 24px;
    text-align: center;
}

.tabs {
    display: flex;
    gap: 0;
    margin-bottom: 24px;
    border-bottom: 2px solid var(--border);
}

.tab {
    flex: 1;
    padding: 10px;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    color: var(--text-light);
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    transition: all 0.2s;
}

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

.auth-form {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.auth-form input,
.auth-form select {
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s;
}

.auth-form input:focus,
.auth-form select:focus {
    border-color: var(--primary);
}

.hidden {
    display: none !important;
}

.error {
    color: var(--error);
    font-size: 0.875rem;
    min-height: 20px;
}

/* Buttons */
.btn-primary {
    padding: 12px 24px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.2s;
}

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

.btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-small {
    padding: 6px 12px;
    background: rgba(255,255,255,0.1);
    color: var(--sidebar-text);
    border: 1px solid rgba(255,255,255,0.2);
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.8rem;
}

.btn-icon {
    width: 44px;
    height: 44px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: white;
    cursor: pointer;
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s;
}

.btn-icon:hover {
    background: var(--bg);
}

.btn-icon.ocr-loading {
    opacity: 0.6;
    cursor: wait;
    animation: pulse 1s infinite;
}

.btn-icon.recording {
    background: var(--error);
    border-color: var(--error);
    animation: pulse 1s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.6; }
}

.badge {
    background: var(--primary);
    color: white;
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 600;
}

/* App layout */
.app-layout {
    display: flex;
    height: 100vh;
}

/* Sidebar */
.sidebar {
    width: 280px;
    background: var(--sidebar-bg);
    color: var(--sidebar-text);
    display: flex;
    flex-direction: column;
    padding: 16px;
    flex-shrink: 0;
}

.sidebar-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
}

.sidebar-header h2 {
    font-size: 1.1rem;
}

.sidebar .btn-primary {
    width: 100%;
    margin-bottom: 16px;
}

.sessions-list {
    flex: 1;
    overflow-y: auto;
}

.session-item {
    padding: 10px 12px;
    border-radius: 8px;
    cursor: pointer;
    margin-bottom: 4px;
    font-size: 0.9rem;
    transition: background 0.2s;
    display: flex;
    align-items: center;
    position: relative;
}

.session-title {
    flex: 1;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.session-menu-btn {
    background: none;
    border: none;
    color: var(--sidebar-text);
    font-size: 1.1rem;
    cursor: pointer;
    padding: 2px 6px;
    border-radius: 4px;
    opacity: 0.5;
    transition: opacity 0.2s;
    flex-shrink: 0;
}

.session-menu-btn:hover {
    opacity: 1;
    background: rgba(255,255,255,0.15);
}

.session-menu {
    position: absolute;
    right: 4px;
    top: 100%;
    background: var(--card-bg);
    border-radius: 8px;
    box-shadow: 0 4px 16px rgba(0,0,0,0.25);
    z-index: 100;
    min-width: 140px;
    overflow: hidden;
}

.session-menu-item {
    padding: 8px 14px;
    font-size: 0.85rem;
    color: var(--text);
    cursor: pointer;
    transition: background 0.15s;
}

.session-menu-item:hover {
    background: var(--bg);
}

.session-menu-item.delete {
    color: var(--error);
}

.session-menu-item.delete:hover {
    background: #fef2f2;
}

.session-item:hover,
.session-item.active {
    background: rgba(255,255,255,0.1);
}

.sidebar-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: 12px;
    border-top: 1px solid rgba(255,255,255,0.1);
    font-size: 0.85rem;
}

.sidebar-footer-actions {
    display: flex;
    gap: 4px;
}

.btn-footer-icon {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255,255,255,0.08);
    border: 1px solid rgba(255,255,255,0.15);
    border-radius: 8px;
    color: var(--sidebar-text);
    font-size: 1.1rem;
    cursor: pointer;
    text-decoration: none;
    transition: background 0.2s;
}

.btn-footer-icon:hover {
    background: rgba(255,255,255,0.18);
}

/* Chat area */
.chat-area {
    flex: 1;
    display: flex;
    flex-direction: column;
    height: 100dvh;
    max-height: 100dvh;
    overflow: hidden;
}

.messages {
    flex: 1;
    overflow-y: auto;
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.welcome-message {
    text-align: center;
    color: var(--text-light);
    margin: auto;
    font-size: 1.1rem;
    line-height: 2;
}

.message {
    max-width: 75%;
    padding: 12px 16px;
    border-radius: var(--radius);
    line-height: 1.6;
    word-wrap: break-word;
}

.message.user {
    align-self: flex-end;
    background: var(--user-msg);
    border-bottom-right-radius: 4px;
}

.message.assistant {
    align-self: flex-start;
    background: var(--assistant-msg);
    border-bottom-left-radius: 4px;
}

.message.streaming::after {
    content: '▊';
    animation: blink 0.7s infinite;
}

@keyframes blink {
    0%, 100% { opacity: 1; }
    50% { opacity: 0; }
}

/* Word-by-word translation message */
.message.translation-msg {
    background: rgba(37, 99, 235, 0.06);
    border-left: 3px solid var(--primary);
    font-size: 0.85em;
    color: var(--text-light);
    white-space: pre-line;
    margin-top: -8px;
}

/* Voice playback in user messages */
.voice-playback {
    margin-bottom: 6px;
}

.voice-playback audio {
    width: 100%;
    max-width: 250px;
    height: 32px;
}

.btn-play-audio {
    padding: 4px 12px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 0.8rem;
    cursor: pointer;
    transition: background 0.2s;
}

.btn-play-audio:hover {
    background: var(--primary-dark);
}

.btn-play-audio:disabled {
    opacity: 0.6;
    cursor: wait;
}

/* Replay TTS button on assistant messages */
.btn-replay-tts {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 3px 10px;
    margin-top: 8px;
    background: none;
    border: 1px solid var(--border);
    border-radius: 14px;
    color: var(--text-secondary);
    font-size: 0.8em;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-replay-tts:hover {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

/* TTS settings */
.tts-settings {
    display: flex;
    gap: 16px;
    padding: 8px 24px;
    background: var(--assistant-msg);
    border-top: 1px solid var(--border);
    align-items: center;
    font-size: 0.85rem;
}

.tts-settings label {
    display: flex;
    align-items: center;
    gap: 6px;
    color: var(--text-light);
}

.tts-settings select {
    padding: 4px 8px;
    border: 1px solid var(--border);
    border-radius: 4px;
    font-size: 0.85rem;
    max-width: 200px;
}

.tts-settings input[type="range"] {
    width: 100px;
}

#tts-rate-val {
    min-width: 24px;
    text-align: center;
}

/* Attachment preview */
.attachment-preview {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 24px;
    background: var(--bg);
    border-top: 1px solid var(--border);
}

.attachment-thumb {
    width: 48px;
    height: 48px;
    object-fit: cover;
    border-radius: 6px;
    border: 1px solid var(--border);
}

.attachment-label {
    flex: 1;
    font-size: 0.85rem;
    color: var(--text-light);
}

.attachment-remove {
    background: none;
    border: none;
    font-size: 1.2rem;
    color: var(--text-light);
    cursor: pointer;
    padding: 4px 8px;
}

.attachment-remove:hover {
    color: var(--error);
}

/* Chat input */
.chat-input-area {
    display: flex;
    gap: 8px;
    padding: 16px 24px;
    border-top: 1px solid var(--border);
    background: white;
    align-items: flex-end;
}

#message-input {
    flex: 1;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    resize: none;
    outline: none;
    max-height: 150px;
    line-height: 1.5;
}

#message-input:focus {
    border-color: var(--primary);
}

/* Sidebar vocabulary button */
.btn-sidebar {
    width: 100%;
    padding: 10px 16px;
    background: rgba(255,255,255,0.05);
    color: var(--sidebar-text);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.9rem;
    text-align: left;
    margin-bottom: 12px;
    transition: background 0.2s;
}

.btn-sidebar:hover {
    background: rgba(255,255,255,0.12);
}

/* Onboarding overlay */
.overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.6);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    backdrop-filter: blur(4px);
}

.overlay-card {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 40px 32px;
    max-width: 420px;
    width: 90%;
    text-align: center;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
}

.overlay-card h2 {
    font-size: 1.5rem;
    margin-bottom: 8px;
}

.overlay-card > p {
    color: var(--text-light);
    margin-bottom: 24px;
}

.onboarding-options {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.btn-block {
    width: 100%;
}

.onboarding-divider {
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--text-light);
    font-size: 0.85rem;
    margin: 4px 0;
}

.onboarding-divider::before,
.onboarding-divider::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border);
}

.onboarding-manual-label {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-bottom: 4px;
}

.onboarding-levels {
    display: flex;
    gap: 8px;
    justify-content: center;
}

.onboarding-level-btn {
    width: 60px;
    height: 44px;
    border: 2px solid var(--border);
    border-radius: 10px;
    background: white;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.onboarding-level-btn:hover {
    border-color: var(--primary);
    color: var(--primary);
    background: #eef2ff;
}

/* Vocabulary panel */
.vocab-panel {
    position: fixed;
    right: 0;
    top: 0;
    bottom: 0;
    width: 360px;
    background: var(--card-bg);
    border-left: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    z-index: 900;
    box-shadow: -4px 0 20px rgba(0,0,0,0.08);
}

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

.vocab-header h3 {
    font-size: 1.1rem;
}

.btn-icon-sm {
    width: 32px;
    height: 32px;
    border: none;
    background: none;
    font-size: 1.3rem;
    cursor: pointer;
    color: var(--text-light);
    border-radius: 6px;
}

.btn-icon-sm:hover {
    background: var(--bg);
}

.vocab-filters {
    display: flex;
    gap: 4px;
    padding: 12px 20px 0;
}

.vocab-filter {
    padding: 6px 12px;
    border: 1px solid var(--border);
    border-radius: 20px;
    background: white;
    font-size: 0.8rem;
    cursor: pointer;
    transition: all 0.2s;
}

.vocab-filter.active {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

.vocab-stats {
    padding: 8px 20px;
    font-size: 0.8rem;
    color: var(--text-light);
}

.vocab-search {
    margin: 0 20px;
    padding: 8px 12px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 0.9rem;
    outline: none;
}

.vocab-search:focus {
    border-color: var(--primary);
}

.vocab-list {
    flex: 1;
    overflow-y: auto;
    padding: 12px 20px;
}

.vocab-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 0;
    border-bottom: 1px solid var(--border);
}

.vocab-item-main {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.vocab-word-text {
    font-weight: 600;
    cursor: pointer;
    color: var(--primary);
}

.vocab-word-text:hover {
    text-decoration: underline;
}

.vocab-translation {
    font-size: 0.85rem;
    color: var(--text-light);
}

.vocab-status-select {
    padding: 4px 8px;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 0.8rem;
    cursor: pointer;
}

.vocab-empty {
    text-align: center;
    color: var(--text-light);
    padding: 40px 0;
}

/* Vocab word in chat messages */
.vocab-word {
    display: inline;
}

.vocab-word strong {
    color: var(--primary-dark);
}

.vocab-word em {
    color: var(--text-light);
    font-size: 0.9em;
}

.vocab-add-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 22px;
    height: 22px;
    border: 1px solid var(--primary);
    border-radius: 50%;
    background: white;
    color: var(--primary);
    font-size: 0.85rem;
    font-weight: 700;
    cursor: pointer;
    margin-left: 4px;
    vertical-align: middle;
    transition: all 0.2s;
}

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

.vocab-add-btn:disabled {
    border-color: var(--success);
    color: var(--success);
    cursor: default;
}

/* Vocab toolbar */
.vocab-toolbar {
    display: flex;
    gap: 8px;
    padding: 0 20px;
    align-items: center;
}

.vocab-toolbar .vocab-search {
    flex: 1;
    margin: 0;
}

/* Grammar info in vocab list */
.vocab-grammar-toggle {
    font-size: 0.75rem;
    color: var(--primary);
    cursor: pointer;
    margin-top: 2px;
}

.vocab-grammar-toggle:hover {
    text-decoration: underline;
}

.vocab-grammar {
    margin-top: 6px;
    font-size: 0.8rem;
}

.grammar-part {
    font-size: 0.75rem;
    color: var(--text-light);
    font-style: italic;
    margin-bottom: 4px;
}

.grammar-label {
    font-size: 0.75rem;
    color: var(--text-light);
    margin-top: 6px;
    margin-bottom: 2px;
}

.grammar-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.8rem;
}

.grammar-table td {
    padding: 2px 6px;
    border-bottom: 1px solid var(--border);
}

.grammar-table td:first-child {
    color: var(--text-light);
    width: 40%;
}

/* Selection popup */
.vocab-selection-popup {
    position: absolute;
    z-index: 1000;
    display: flex;
    gap: 4px;
    border-radius: 6px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.2);
    transition: opacity 0.15s;
}

.vocab-selection-popup button {
    padding: 4px 12px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 0.8rem;
    cursor: pointer;
    white-space: nowrap;
    transition: background 0.2s;
}

.vocab-selection-popup button:hover {
    background: var(--primary-dark);
}

/* Add word dialog */
.vocab-add-dialog {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1100;
}

.vocab-dialog-content {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 24px;
    width: 90%;
    max-width: 400px;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
}

.vocab-dialog-content h4 {
    margin-bottom: 12px;
}

.vocab-dialog-content input {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
    margin-bottom: 12px;
    outline: none;
}

.vocab-dialog-content input:focus {
    border-color: var(--primary);
}

.vocab-dialog-result {
    padding: 12px;
    background: var(--bg);
    border-radius: 8px;
    margin-bottom: 12px;
    font-size: 0.9rem;
}

.vocab-dialog-actions {
    display: flex;
    gap: 8px;
}

.vocab-dialog-actions .btn-small {
    color: var(--text);
    border-color: var(--border);
}

/* Pronunciation block */
.pronunciation-block {
    margin-top: 8px;
    padding: 8px 12px;
    background: rgba(37, 99, 235, 0.08);
    border-left: 3px solid var(--primary);
    border-radius: 0 8px 8px 0;
    font-size: 0.85rem;
}

.pron-header {
    margin-bottom: 4px;
}

.pron-feedback {
    color: var(--text);
    margin-bottom: 4px;
}

.pron-problems {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-top: 4px;
}

.pron-problem {
    background: rgba(239, 68, 68, 0.1);
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.8rem;
}

/* Settings page */
.settings-page {
    min-height: 100vh;
    background: var(--bg);
    display: flex;
    justify-content: center;
    padding: 40px 20px;
}

.settings-container {
    width: 100%;
    max-width: 600px;
}

.settings-header {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 32px;
}

.settings-header h1 {
    font-size: 1.5rem;
}

.settings-back {
    color: var(--primary);
    text-decoration: none;
    font-size: 0.95rem;
}

.settings-back:hover {
    text-decoration: underline;
}

.settings-section {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 20px 24px;
    margin-bottom: 16px;
    border: 1px solid var(--border);
}

.settings-section h2 {
    font-size: 1.1rem;
    margin-bottom: 12px;
}

.settings-label {
    display: flex;
    flex-direction: column;
    gap: 4px;
    margin-bottom: 12px;
    font-size: 0.9rem;
    color: var(--text-light);
}

.settings-label input,
.settings-label select,
.settings-section textarea {
    padding: 10px 14px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    outline: none;
    width: 100%;
    transition: border-color 0.2s;
}

.settings-label input:focus,
.settings-label select:focus,
.settings-section textarea:focus {
    border-color: var(--primary);
}

.settings-section textarea {
    resize: vertical;
    min-height: 80px;
}

.settings-hint {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-bottom: 12px;
}

.btn-link {
    background: none;
    border: none;
    color: var(--primary);
    cursor: pointer;
    font-size: inherit;
    padding: 0;
}

.btn-link:hover {
    text-decoration: underline;
}

.settings-default-prompt {
    background: var(--bg);
    border-radius: 8px;
    padding: 12px;
    font-size: 0.85rem;
    white-space: pre-wrap;
    margin-bottom: 12px;
    max-height: 200px;
    overflow-y: auto;
}

/* Settings toggle checkbox */
.settings-toggle {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 10px;
    margin-bottom: 12px;
    font-size: 0.9rem;
    color: var(--text);
    cursor: pointer;
}

.settings-toggle input[type="checkbox"] {
    width: 18px;
    height: 18px;
    flex-shrink: 0;
    accent-color: var(--primary);
    cursor: pointer;
}

.settings-success {
    background: #dcfce7;
    color: #166534;
    padding: 10px 16px;
    border-radius: 8px;
    margin-bottom: 16px;
    font-size: 0.9rem;
}

/* Visual polish — shadows & transitions */
.message {
    box-shadow: var(--shadow-sm);
}

.chat-input-area {
    box-shadow: 0 -2px 8px rgba(0,0,0,0.04);
}

.sidebar {
    box-shadow: var(--shadow-lg);
}

.btn-primary,
.btn-small,
.btn-icon,
.btn-icon-sm,
.btn-sidebar,
.onboarding-level-btn,
.vocab-filter,
.session-item {
    transition: all 0.2s ease;
}

.btn-primary:active,
.btn-small:active,
.btn-icon:active,
.btn-icon-sm:active,
.btn-sidebar:active,
.onboarding-level-btn:active,
.vocab-filter:active {
    transform: scale(0.97);
}

/* Focus ring */
.auth-form input:focus,
.auth-form select:focus,
#message-input:focus,
.vocab-search:focus,
.settings-label input:focus,
.settings-label select:focus,
.settings-section textarea:focus {
    box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
}

.auth-card:focus-within {
    box-shadow: 0 20px 60px rgba(0,0,0,0.35);
}

/* Thin scrollbar */
.messages::-webkit-scrollbar,
.sessions-list::-webkit-scrollbar,
.vocab-list::-webkit-scrollbar {
    width: 4px;
}

.messages::-webkit-scrollbar-thumb,
.sessions-list::-webkit-scrollbar-thumb,
.vocab-list::-webkit-scrollbar-thumb {
    background: rgba(0,0,0,0.15);
    border-radius: 2px;
}

/* Hamburger toggle — hidden on desktop */
.sidebar-toggle {
    display: none;
    position: fixed;
    top: 12px;
    left: 12px;
    z-index: 1001;
    width: 44px;
    height: 44px;
    border: none;
    border-radius: 8px;
    background: var(--sidebar-bg);
    color: white;
    font-size: 1.4rem;
    cursor: pointer;
    box-shadow: var(--shadow-md);
    align-items: center;
    justify-content: center;
}

/* Backdrop — hidden on desktop */
.sidebar-backdrop {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    z-index: 899;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.sidebar-backdrop.open {
    opacity: 1;
}

/* ===== TABLET (768px) ===== */
@media (max-width: 768px) {
    .sidebar-toggle {
        display: flex;
    }

    .sidebar-backdrop {
        display: block;
        pointer-events: none;
    }

    .sidebar-backdrop.open {
        pointer-events: auto;
    }

    .sidebar {
        position: fixed;
        top: 0;
        left: 0;
        bottom: 0;
        width: 280px;
        z-index: 900;
        transform: translateX(-100%);
        transition: transform 0.3s ease;
    }

    .sidebar.open {
        transform: translateX(0);
    }

    .messages {
        padding: 16px;
    }

    .chat-input-area {
        padding: 12px 16px;
    }

    .message {
        max-width: 85%;
    }

    .vocab-panel {
        width: 100%;
    }

    .vocab-header .btn-icon-sm {
        width: 44px;
        height: 44px;
        font-size: 1.5rem;
    }

    .vocab-header {
        position: sticky;
        top: 0;
        background: var(--card-bg);
        z-index: 1;
    }

    .tts-settings {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
        padding: 8px 16px;
    }

    .settings-page {
        padding: 24px 12px;
    }

    .auth-card {
        padding: 28px 20px 24px;
    }
}

/* ===== PHONE (480px) ===== */
@media (max-width: 480px) {
    .message {
        max-width: 92%;
        padding: 10px 12px;
    }

    .auth-card {
        padding: 24px 16px 20px;
    }

    .settings-section {
        padding: 16px;
    }

    /* Round send button with icon */
    #send-btn {
        width: 44px;
        height: 44px;
        min-width: 44px;
        padding: 0;
        border-radius: 50%;
        font-size: 0;
    }

    #send-btn::after {
        content: '➤';
        font-size: 1.2rem;
    }

    .onboarding-levels {
        flex-wrap: wrap;
    }

    .pronunciation-block {
        font-size: 0.8rem;
        padding: 6px 10px;
    }
}

/* Touch targets — enlarged for mobile */
@media (max-width: 768px) {
    .btn-small {
        padding: 8px 14px;
    }

    .btn-icon-sm {
        width: 40px;
        height: 40px;
    }

    .vocab-filter {
        padding: 8px 14px;
    }

    .session-item {
        min-height: 44px;
    }
}

/* YOLO Overlay & Visualizer */
.yolo-overlay {
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.85); /* Sleek slate dark background */
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    color: #f8fafc;
    transition: opacity 0.3s ease;
}

.yolo-overlay.hidden {
    display: none !important;
}

.yolo-container {
    width: 100%;
    max-width: 550px;
    height: 90vh;
    max-height: 800px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 28px;
    background: rgba(30, 41, 59, 0.7);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 24px;
    box-shadow: var(--shadow-lg);
}

.yolo-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding-bottom: 16px;
}

.yolo-badge {
    background: linear-gradient(135deg, #f59e0b, #ef4444);
    color: white;
    padding: 3px 8px;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    display: inline-block;
    margin-bottom: 4px;
}

.yolo-session-title {
    font-size: 1.25rem;
    font-weight: 600;
}

.yolo-close-btn {
    background: rgba(255, 255, 255, 0.1);
    border: none;
    color: white;
    font-size: 1.5rem;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s;
}

.yolo-close-btn:hover {
    background: rgba(239, 68, 68, 0.4);
}

/* Orb Visualization */
.yolo-visualizer-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    margin: 30px 0;
}

.yolo-orb-outer {
    position: relative;
    width: 200px;
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
}

.yolo-orb {
    width: 140px;
    height: 140px;
    border-radius: 50%;
    background: linear-gradient(135deg, #3b82f6, #8b5cf6);
    box-shadow: 0 0 40px rgba(59, 130, 246, 0.5);
    transition: transform 0.1s ease, background 0.3s ease, box-shadow 0.3s ease;
}

/* Breathing animation for Idle */
.yolo-orb.state-idle {
    animation: orb-breathe 3s infinite ease-in-out;
    background: linear-gradient(135deg, #1e40af, #3b82f6);
    box-shadow: 0 0 30px rgba(59, 130, 246, 0.3);
}

/* Thinking animation - spinning and color shifting */
.yolo-orb.state-thinking {
    animation: orb-think 2s infinite linear;
    background: linear-gradient(135deg, #8b5cf6, #ec4899);
    box-shadow: 0 0 40px rgba(139, 92, 246, 0.6);
}

/* Speaking ripple effect */
.yolo-orb.state-speaking {
    animation: orb-speak 1.5s infinite ease-in-out;
    background: linear-gradient(135deg, #10b981, #3b82f6);
    box-shadow: 0 0 45px rgba(16, 185, 129, 0.5);
}

/* Listening state - reacts to volume via JS scale */
.yolo-orb.state-listening {
    background: linear-gradient(135deg, #ef4444, #f59e0b);
    box-shadow: 0 0 40px rgba(239, 68, 68, 0.5);
}

@keyframes orb-breathe {
    0%, 100% { transform: scale(1); opacity: 0.9; }
    50% { transform: scale(1.08); opacity: 1; box-shadow: 0 0 45px rgba(59, 130, 246, 0.5); }
}

@keyframes orb-think {
    0% { transform: rotate(0deg) scale(1); filter: hue-rotate(0deg); }
    50% { transform: rotate(180deg) scale(1.05); filter: hue-rotate(90deg); }
    100% { transform: rotate(360deg) scale(1); filter: hue-rotate(0deg); }
}

@keyframes orb-speak {
    0%, 100% { transform: scale(1.02); }
    50% { transform: scale(1.12); box-shadow: 0 0 50px rgba(16, 185, 129, 0.7); }
}

.yolo-status {
    font-size: 1.1rem;
    font-weight: 500;
    color: #e2e8f0;
    text-align: center;
    min-height: 1.6em;
}

/* Collapsible Text Preview */
.yolo-preview-container {
    background: rgba(15, 23, 42, 0.4);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: 16px;
    padding: 16px;
    margin-bottom: 20px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    width: 100%;
}

.yolo-preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    color: #94a3b8;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    padding-bottom: 6px;
}

.yolo-text-preview {
    font-size: 0.95rem;
    max-height: 120px;
    height: 120px;
    overflow-y: auto;
    color: #e2e8f0;
    line-height: 1.5;
    text-align: left;
}

.yolo-text-preview.hidden {
    display: none !important;
}

.yolo-text-preview .yolo-line {
    margin-bottom: 8px;
    border-bottom: 1px dashed rgba(255, 255, 255, 0.03);
    padding-bottom: 6px;
}

.yolo-text-preview .yolo-line.user {
    color: #93c5fd;
}

.yolo-text-preview .yolo-line.assistant {
    color: #a7f3d0;
}

.yolo-pron-score {
    margin-top: 4px;
    display: block;
}

/* Controls */
.yolo-controls {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 16px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    width: 100%;
}

.yolo-control-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    font-size: 0.85rem;
    color: #94a3b8;
}

.yolo-control-row input[type="range"] {
    flex: 1;
    accent-color: #3b82f6;
    height: 6px;
    border-radius: 3px;
    outline: none;
}

.yolo-buttons {
    display: flex;
    gap: 12px;
    width: 100%;
}

.yolo-btn-primary {
    flex: 1;
    padding: 14px;
    border: none;
    border-radius: 12px;
    background: linear-gradient(135deg, #3b82f6, #1d4ed8);
    color: white;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, background 0.2s;
}

.yolo-btn-primary:hover {
    background: linear-gradient(135deg, #2563eb, #1e40af);
    transform: translateY(-1px);
}

.yolo-btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.yolo-btn-secondary {
    width: 56px;
    height: 52px;
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.05);
    color: white;
    font-size: 1.25rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s;
}

.yolo-btn-secondary:hover {
    background: rgba(255, 255, 255, 0.15);
}

.yolo-btn-secondary.muted {
    background: rgba(239, 68, 68, 0.3);
    border-color: rgba(239, 68, 68, 0.5);
    color: #f87171;
}

@media (max-width: 580px) {
    .yolo-container {
        height: 100vh;
        max-height: 100vh;
        border-radius: 0;
        border: none;
    }
}

/* YOLO Floating Action Button */
.yolo-floating-btn {
    position: fixed;
    bottom: 80px;
    right: 24px;
    padding: 14px 24px;
    background: linear-gradient(135deg, #2563eb, #7c3aed);
    color: white;
    border: none;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    box-shadow: 0 10px 25px rgba(124, 58, 237, 0.4);
    z-index: 800;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    animation: pulse-yolo 2s infinite;
}

.yolo-floating-btn:hover {
    transform: scale(1.05) translateY(-2px);
    box-shadow: 0 14px 30px rgba(124, 58, 237, 0.5);
}

.yolo-floating-btn.hidden {
    display: none !important;
}

@keyframes pulse-yolo {
    0%, 100% {
        box-shadow: 0 10px 25px rgba(124, 58, 237, 0.4);
    }
    50% {
        box-shadow: 0 10px 35px rgba(124, 58, 237, 0.7);
    }
}