/* ==========================================
   Layout - App Structure
   ========================================== */

/* App Container */
#app {
    display: flex;
    flex-direction: column;
    height: 100%;
    height: 100dvh;
    padding-top: var(--safe-area-inset-top);
    padding-bottom: var(--safe-area-inset-bottom);
    padding-left: var(--safe-area-inset-left);
    padding-right: var(--safe-area-inset-right);
}

/* ==========================================
   Header
   ========================================== */

.app-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-panel-glass);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-subtle);
    flex-shrink: 0;
    min-height: 60px;
    position: relative;
    z-index: var(--z-sticky);
}

.header-left,
.header-right {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.logo-container {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.logo {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-sm);
}

.logo-text {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-main);
}

.mode-container,
.actions-container {
    position: relative;
    display: flex;
    align-items: center;
}

/* Header Menu Dropdown */
.header-menu {
    position: absolute;
    top: calc(100% + var(--spacing-xs));
    right: 0;
    background: var(--bg-elevated);
    border: 1px solid var(--border-default);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    min-width: 200px;
    padding: var(--spacing-xs);
    z-index: var(--z-dropdown);
}

.menu-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    color: var(--text-main);
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: background var(--transition-fast);
    text-align: left;
}

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

.menu-icon {
    width: 18px;
    height: 18px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.menu-icon svg {
    width: 18px;
    height: 18px;
}

.menu-divider {
    height: 1px;
    background: var(--border-subtle);
    margin: var(--spacing-xs) 0;
}

/* Mode Dropdown */
.mode-dropdown {
    position: absolute;
    top: calc(100% + var(--spacing-xs));
    right: 0;
    background: var(--bg-elevated);
    border: 1px solid var(--border-default);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    min-width: 180px;
    padding: var(--spacing-xs);
    z-index: var(--z-dropdown);
}

.mode-option {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    color: var(--text-main);
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: background var(--transition-fast);
}

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

.mode-option.active {
    background: var(--brand-primary-glow);
    color: var(--brand-primary);
}

/* ==========================================
   Messages Container
   ========================================== */

.messages-container {
    flex: 1;
    overflow-y: auto;
    overflow-x: hidden;
    padding: var(--spacing-md);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

/* Welcome Splash */
.welcome-splash {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    flex: 1;
    text-align: center;
    padding: var(--spacing-xl);
    opacity: 0.9;
}

.welcome-splash.hidden {
    display: none;
}

.welcome-logo {
    width: 80px;
    height: 80px;
    margin-bottom: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

.welcome-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: var(--spacing-sm);
}

.welcome-subtitle {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
}

/* ==========================================
   Input Area
   ========================================== */

.input-area {
    padding: var(--spacing-md);
    background: transparent;
    flex-shrink: 0;
    max-width: 800px;
    margin: 0 auto;
    width: 100%;
}

.input-wrapper {
    display: flex;
    align-items: flex-end;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    background: var(--bg-panel-glass);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border-strong);
    border-radius: 20px;
    box-shadow: var(--shadow-lg);
    transition: all var(--transition-normal);
}

/* Intelligent Button Layout */
.input-actions,
.input-actions-left {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    transition: all var(--transition-normal);
}

.input-area.expanded .input-actions,
.input-area.expanded .input-actions-left {
    flex-direction: column;
    padding-bottom: var(--spacing-xs);
}

.input-wrapper:focus-within {
    border-color: var(--brand-primary);
    box-shadow: 0 0 0 3px var(--brand-primary-glow);
}

.input-field {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-main);
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.5;
    resize: none;
    min-height: 24px;
    max-height: 200px;
    padding: var(--spacing-xs) var(--spacing-sm);
}

.input-field::placeholder {
    color: var(--input-placeholder);
}

.input-field:focus {
    outline: none;
}

/* Attachments Preview */
.attachments-preview {
    display: flex;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
    overflow-x: auto;
}

.attachments-preview.hidden {
    display: none;
}

.attachment-thumbnail {
    position: relative;
    width: 64px;
    height: 64px;
    border-radius: var(--radius-sm);
    overflow: hidden;
    flex-shrink: 0;
    background: var(--bg-surface);
    border: 1px solid var(--border-default);
}

.attachment-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.attachment-thumbnail .remove-btn {
    position: absolute;
    top: 2px;
    right: 2px;
    width: 20px;
    height: 20px;
    background: var(--error);
    border: none;
    border-radius: 50%;
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
}

/* ==========================================
   Thinking Indicator
   ========================================== */

.thinking-indicator {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-elevated);
    border-radius: var(--radius-md);
    position: fixed;
    bottom: 100px;
    left: 50%;
    transform: translateX(-50%);
    box-shadow: var(--shadow-lg);
    z-index: var(--z-sticky);
}

.thinking-indicator.hidden {
    display: none;
}

.thinking-spinner {
    width: 16px;
    height: 16px;
    border: 2px solid var(--border-default);
    border-top-color: var(--brand-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

.thinking-text {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
}

/* ==========================================
   Responsive Design
   ========================================== */

@media (max-width: 768px) {
    .app-header {
        padding: var(--spacing-xs) var(--spacing-sm);
    }

    .logo-text {
        font-size: var(--font-size-md);
    }

    .messages-container {
        padding: var(--spacing-sm);
    }

    .input-area {
        padding: var(--spacing-xs) var(--spacing-sm);
    }

    .welcome-logo {
        width: 60px;
        height: 60px;
    }

    .welcome-title {
        font-size: 1.5rem;
    }
}

@media (max-width: 480px) {
    .input-wrapper {
        padding: var(--spacing-xs);
    }

    .btn-icon {
        width: 36px;
        height: 36px;
    }
}