:root {
    --bg-gradient-start: #667eea;
    --bg-gradient-end: #764ba2;
    --container-bg: #ffffff;
    --header-gradient-start: #2c3e50;
    --header-gradient-end: #34495e;
    --header-text: #ffffff;
    --messages-bg: #f8f9fa;
    --message-user-bg-start: #667eea;
    --message-user-bg-end: #764ba2;
    --message-user-text: #ffffff;
    --message-assistant-bg: #ffffff;
    --message-assistant-text: #333333;
    --message-assistant-border: #e1e8ed;
    --input-border: #e1e8ed;
    --input-focus-border: #667eea;
    --input-bg: #ffffff;
    --input-text: #333333;
    --button-secondary-bg: #f8f9fa;
    --button-secondary-text: #6c757d;
    --button-secondary-border: #dee2e6;
    --button-secondary-hover: #e9ecef;
    --loading-text: #666666;
    --control-bg: rgba(255, 255, 255, 0.95);
    --control-hover-bg: rgba(255, 255, 255, 1);
    --control-text: #333333;
    --control-border: rgba(0, 0, 0, 0.1);
    --shadow-color: rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
    --bg-gradient-start: #1a1a2e;
    --bg-gradient-end: #16213e;
    --container-bg: #2d3748;
    --header-gradient-start: #1a202c;
    --header-gradient-end: #2d3748;
    --header-text: #ffffff;
    --messages-bg: #4a5568;
    --message-user-bg-start: #667eea;
    --message-user-bg-end: #764ba2;
    --message-user-text: #ffffff;
    --message-assistant-bg: #718096;
    --message-assistant-text: #ffffff;
    --message-assistant-border: #4a5568;
    --input-border: #4a5568;
    --input-focus-border: #667eea;
    --input-bg: #4a5568;
    --input-text: #ffffff;
    --button-secondary-bg: #4a5568;
    --button-secondary-text: #cbd5e0;
    --button-secondary-border: #718096;
    --button-secondary-hover: #718096;
    --loading-text: #cbd5e0;
    --control-bg: rgba(45, 55, 72, 0.95);
    --control-hover-bg: rgba(45, 55, 72, 1);
    --control-text: #ffffff;
    --control-border: rgba(255, 255, 255, 0.1);
    --shadow-color: rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    min-height: 100vh;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

/* Desktop layout */
@media (min-width: 769px) {
    body {
        display: flex;
        align-items: center;
        justify-content: center;
        padding: 20px;
        overflow: auto;
    }
}

/* External Controls */
.external-controls {
    position: fixed;
    top: 20px;
    right: 20px;
    display: flex;
    gap: 12px;
    z-index: 1000;
}

.control-item {
    background: var(--control-bg);
    border: 1px solid var(--control-border);
    border-radius: 12px;
    padding: 10px 14px;
    color: var(--control-text);
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s ease;
    backdrop-filter: blur(20px);
    box-shadow: 0 4px 12px var(--shadow-color);
    display: flex;
    align-items: center;
    gap: 8px;
    min-width: 44px;
    justify-content: center;
}

.control-item:hover {
    background: var(--control-hover-bg);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--shadow-color);
}

.theme-toggle {
    border: none;
    font-family: inherit;
}

.language-selector {
    position: relative;
    display: flex;
    align-items: center;
    background: var(--control-bg);
    border: 1px solid var(--control-border);
    border-radius: 12px;
    backdrop-filter: blur(20px);
    transition: all 0.3s ease;
    overflow: visible;
    cursor: pointer;
}

.language-selector:hover {
    background: var(--control-hover-bg);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--shadow-color);
}

.language-selector.open {
    border-bottom-left-radius: 0;
    border-bottom-right-radius: 0;
}

.language-current {
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 10px 14px 10px 8px;
    color: var(--control-text);
    font-size: 14px;
    font-weight: 500;
    min-width: 80px;
    background: transparent;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
    outline: none;
    position: relative;
}

.language-current::after {
    content: '▼';
    font-size: 10px;
    margin-left: auto;
    transition: transform 0.3s ease;
}

.language-selector.open .language-current::after {
    transform: rotate(180deg);
}

.language-icon {
    font-size: 16px;
    margin-left: 12px;
    margin-right: 4px;
    display: flex;
    align-items: center;
}

.language-options {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--control-bg);
    border: 1px solid var(--control-border);
    border-top: none;
    border-radius: 0 0 12px 12px;
    backdrop-filter: blur(20px);
    box-shadow: 0 4px 12px var(--shadow-color);
    z-index: 1001;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    max-height: 300px;
    overflow-y: auto;
}

.language-selector.open .language-options {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.language-option {
    padding: 12px 16px;
    color: var(--control-text);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
    background: transparent;
    width: 100%;
    text-align: left;
    display: flex;
    align-items: center;
    gap: 8px;
    min-height: 44px;
}

.language-option:hover {
    background: var(--control-hover-bg);
}

.language-option.selected {
    background: var(--input-focus-border);
    color: white;
}

.language-option.selected:hover {
    background: var(--input-focus-border);
}

/* Hide the original select */
.language-dropdown {
    display: none;
}

/* Desktop Chat Container */
.chat-container {
    background: var(--container-bg);
    border-radius: 20px;
    box-shadow: 0 20px 40px var(--shadow-color);
    width: 100%;
    max-width: 800px;
    height: 80vh;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: all 0.3s ease;
}

.chat-header {
    background: linear-gradient(135deg, var(--header-gradient-start), var(--header-gradient-end));
    color: var(--header-text);
    padding: 30px 20px;
    text-align: center;
    border-radius: 20px 20px 0 0;
    flex-shrink: 0;
}

.chat-header h1 {
    font-size: 1.5rem;
    margin-bottom: 5px;
}

.chat-header p {
    opacity: 0.8;
    font-size: 0.9rem;
}

.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    background: var(--messages-bg);
    transition: all 0.3s ease;
    -webkit-overflow-scrolling: touch;
}

.message {
    margin-bottom: 20px;
    display: flex;
    align-items: flex-start;
    animation: fadeIn 0.3s ease-in;
}

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

.message.user {
    justify-content: flex-end;
}

.message-content {
    max-width: 70%;
    padding: 12px 28px;
    border-radius: 18px;
    line-height: 1.4;
    word-wrap: break-word;
    transition: all 0.3s ease;
}

.message.user .message-content {
    background: linear-gradient(135deg, var(--message-user-bg-start), var(--message-user-bg-end));
    color: var(--message-user-text);
    border-bottom-right-radius: 4px;
}

.message.assistant .message-content {
    background: var(--message-assistant-bg);
    color: var(--message-assistant-text);
    border: 1px solid var(--message-assistant-border);
    border-bottom-left-radius: 4px;
}

.chat-input-container {
    padding: 20px;
    background: var(--container-bg);
    border-top: 1px solid var(--message-assistant-border);
    transition: all 0.3s ease;
    flex-shrink: 0;
}

.chat-input-form {
    display: flex;
    gap: 10px;
}

.chat-input {
    flex: 1;
    padding: 12px 16px;
    border: 2px solid var(--input-border);
    border-radius: 25px;
    font-size: 16px;
    outline: none;
    transition: all 0.3s ease;
    background: var(--input-bg);
    color: var(--input-text);
}

.chat-input:focus {
    border-color: var(--input-focus-border);
}

.chat-input::placeholder {
    color: var(--loading-text);
}

.send-button, .clear-button {
    padding: 12px 20px;
    border: none;
    border-radius: 25px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 14px;
}

.send-button {
    background: linear-gradient(135deg, var(--message-user-bg-start), var(--message-user-bg-end));
    color: var(--message-user-text);
}

.send-button:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
}

.send-button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.clear-button {
    background: var(--button-secondary-bg);
    color: var(--button-secondary-text);
    border: 1px solid var(--button-secondary-border);
}

.clear-button:hover {
    background: var(--button-secondary-hover);
}

.loading {
    display: none;
    padding: 12px;
    text-align: center;
    color: var(--loading-text);
    font-style: italic;
    transition: all 0.3s ease;
    flex-shrink: 0;
}

.loading.show {
    display: block;
}

.button-group {
    display: flex;
    gap: 10px;
}

.input-wrapper {
    position: relative;
    flex: 1;
}

.character-counter {
    position: absolute;
    bottom: 8px;
    right: 12px;
    font-size: 12px;
    color: var(--text-secondary, #666);
    background: var(--background-primary, #fff);
    padding: 2px 6px;
    border-radius: 10px;
    pointer-events: none;
    z-index: 10;
    transition: color 0.2s ease;
}

.character-counter.warning {
    color: #ff9800;
}

.character-counter.error {
    color: #f44336;
    font-weight: 600;
}

.chat-input.over-limit {
    border-color: #f44336 !important;
    box-shadow: 0 0 0 2px rgba(244, 67, 54, 0.2) !important;
}

.send-button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Adjust input padding to make room for counter */
.chat-input {
    padding-right: 80px !important;
    padding-bottom: 32px !important;
}

/* Dark mode support for character counter */
[data-theme="dark"] .character-counter {
    color: #999;
    background: #2a2a2a;
}

[data-theme="dark"] .character-counter.warning {
    color: #ffb74d;
}

[data-theme="dark"] .character-counter.error {
    color: #ef5350;
}

/* Mobile-specific styles - Native experience with shrinking container */
@media (max-width: 768px) {
    body {
        padding: 0;
        overflow: hidden;
        position: fixed;
        width: 100%;
        height: 100%;
        top: 0;
        left: 0;
        /* Use dynamic viewport height that excludes keyboard */
        height: 100dvh;
        height: 100svh; /* Small viewport height - excludes keyboard */
    }

    .external-controls {
        position: fixed;
        top: env(safe-area-inset-top, 10px);
        right: 10px;
        left: 10px;
        display: flex;
        justify-content: flex-end;
        gap: 8px;
        z-index: 1000;
        pointer-events: none;
    }

    .control-item {
        padding: 8px 12px;
        font-size: 12px;
        min-width: 40px;
        border-radius: 10px;
        pointer-events: auto;
    }

    .language-selector {
        border-radius: 10px;
        pointer-events: auto;
    }

    .language-selector.open {
        border-bottom-left-radius: 0;
        border-bottom-right-radius: 0;
    }

    .language-current {
        padding: 8px 12px 8px 4px;
        font-size: 12px;
        min-width: 60px;
    }

    .language-options {
        border-radius: 0 0 10px 10px;
        max-height: 200px;
    }

    .language-option {
        padding: 10px 12px;
        font-size: 12px;
        min-height: 40px;
    }

    .language-icon {
        font-size: 14px;
        margin-left: 8px;
        margin-right: 2px;
    }

    /* Mobile chat container - uses viewport dimensions */
    .chat-container {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        width: 100%;
        /* Use small viewport height to exclude keyboard */
        height: 100svh;
        height: 100dvh; /* Fallback for browsers that don't support svh */
        max-width: 100%;
        border-radius: 0;
        box-shadow: none;
        margin: 0;
        overflow: hidden;
        display: flex;
        flex-direction: column;
    }

    .chat-header {
        padding: calc(env(safe-area-inset-top, 10px) + 50px) 15px 20px 15px;
        border-radius: 0;
        background: linear-gradient(135deg, var(--header-gradient-start), var(--header-gradient-end));
        flex-shrink: 0;
    }

    .chat-header h1 {
        font-size: 1.3rem;
    }

    .chat-header p {
        font-size: 0.8rem;
    }

    .chat-messages {
        flex: 1;
        padding: 15px;
        overflow-y: auto;
        -webkit-overflow-scrolling: touch;
        overscroll-behavior: contain;
        /* Ensure it takes available space */
        min-height: 0;
    }

    .message-content {
        max-width: 85%;
        font-size: 14px;
    }

    .button-group {
        flex-direction: column;
    }

    .send-button, .clear-button {
        padding: 12px 16px;
        font-size: 14px;
        border-radius: 25px;
    }

    .chat-input {
        font-size: 16px;
        padding: 12px 16px;
        border-radius: 25px;
    }

    .chat-input-container {
        padding: 15px;
        /* Use safe area inset for devices with home indicator */
        padding-bottom: calc(15px + env(safe-area-inset-bottom, 0px));
        flex-shrink: 0;
    }

    .loading {
        padding: 8px 15px;
    }
}

@media (max-width: 480px) {
    .external-controls {
        top: calc(env(safe-area-inset-top, 8px) + 0px);
        right: 8px;
        left: 8px;
        gap: 6px;
    }

    .control-item {
        padding: 6px 8px;
        font-size: 11px;
        min-width: 36px;
        border-radius: 8px;
    }

    .language-selector {
        border-radius: 8px;
    }

    .language-selector.open {
        border-bottom-left-radius: 0;
        border-bottom-right-radius: 0;
    }

    .language-current {
        min-width: 45px;
        padding: 6px 8px 6px 2px;
        font-size: 11px;
    }

    .language-options {
        border-radius: 0 0 8px 8px;
        max-height: 180px;
    }

    .language-option {
        padding: 8px 10px;
        font-size: 11px;
        min-height: 36px;
    }

    .language-icon {
        font-size: 12px;
        margin-left: 6px;
        margin-right: 1px;
    }

    .chat-header {
        padding: calc(env(safe-area-inset-top, 8px) + 45px) 12px 15px 12px;
    }

    .chat-header h1 {
        font-size: 1.2rem;
    }

    .chat-header p {
        font-size: 0.75rem;
    }

    .chat-messages {
        padding: 12px;
    }

    .message-content {
        max-width: 90%;
        padding: 10px 20px;
        font-size: 13px;
    }

    .chat-input-container {
        padding: 12px;
        padding-bottom: calc(12px + env(safe-area-inset-bottom, 0px));
    }

    .chat-input {
        padding: 10px 14px;
        border-radius: 20px;
        font-size: 16px;
    }

    .send-button, .clear-button {
        padding: 10px 14px;
        font-size: 13px;
        border-radius: 20px;
    }

    .button-group {
        gap: 8px;
    }
}

/* Extra small screens */
@media (max-width: 360px) {
    .external-controls {
        flex-direction: row;
        justify-content: center;
        gap: 4px;
        top: calc(env(safe-area-inset-top, 5px) + 0px);
    }

    .control-item {
        padding: 5px 6px;
        min-width: 32px;
    }

    .language-current {
        min-width: 40px;
        padding: 5px 6px 5px 2px;
    }

    .language-options {
        max-height: 160px;
    }

    .language-option {
        padding: 6px 8px;
        font-size: 10px;
        min-height: 32px;
    }

    .language-icon {
        font-size: 10px;
        margin-left: 4px;
        margin-right: 1px;
    }

    .chat-header {
        padding: calc(env(safe-area-inset-top, 5px) + 40px) 10px 12px 10px;
    }

    .message-content {
        max-width: 95%;
        padding: 8px 16px;
        font-size: 12px;
    }

    .chat-input-container {
        padding: 10px;
        padding-bottom: calc(10px + env(safe-area-inset-bottom, 0px));
    }

    .chat-input {
        padding: 8px 12px;
        font-size: 16px;
    }

    .send-button, .clear-button {
        padding: 8px 12px;
        font-size: 12px;
    }
}

/* Landscape orientation adjustments for mobile */
@media (max-width: 768px) and (orientation: landscape) {
    .external-controls {
        top: calc(env(safe-area-inset-top, 5px) + 0px);
        gap: 6px;
    }

    .control-item {
        padding: 6px 10px;
        font-size: 11px;
    }

    .chat-header {
        padding: calc(env(safe-area-inset-top, 5px) + 35px) 15px 12px 15px;
    }

    .chat-header h1 {
        font-size: 1.1rem;
    }

    .chat-header p {
        font-size: 0.7rem;
    }

    .chat-messages {
        padding: 10px 15px;
    }

    .chat-input-container {
        padding: 10px 15px;
        padding-bottom: calc(10px + env(safe-area-inset-bottom, 0px));
    }
}

/* Enhanced viewport support for better keyboard handling */
@supports (height: 100svh) {
    @media (max-width: 768px) {
        body {
            height: 100svh; /* Small viewport height - excludes virtual keyboard */
        }

        .chat-container {
            height: 100svh;
        }
    }
}

@supports (height: 100dvh) {
    @media (max-width: 768px) {
        body {
            height: 100dvh; /* Dynamic viewport height */
        }

        .chat-container {
            height: 100dvh;
        }
    }
}