:root {
    --header-height: 70px;
    --primary-color: #2563EB;
    --primary-hover: #1D4ED8;
    --primary-light: #DBEAFE;
    --border-color: #E5E7EB;
    --background-color: #F9FAFB;
    --text-color: #111827;
    --text-muted: #6B7280;
    --white: #ffffff;
    --danger-color: #DC2626;
    --danger-hover: #B91C1C;
    --success-color: #059669;
    --success-hover: #047857;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius: 8px;
    --radius-lg: 12px;
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Inter', 'Sarabun', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    margin: 0;
    background-color: var(--background-color);
    color: var(--text-color);
    font-size: 15px;
    line-height: 1.6;
}

.view {
    width: 100%;
    height: 100vh;
}

.hidden {
    display: none !important;
}

header {
    background: var(--white);
    padding: 0 2rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: var(--header-height);
    flex-shrink: 0;
    box-shadow: var(--shadow-sm);
}

header h1, header h2 {
    margin: 0;
    font-size: 1.375rem;
    font-weight: 600;
    color: var(--text-color);
}

main {
    height: calc(100vh - var(--header-height));
    overflow-y: auto;
}

button {
    padding: 10px 18px;
    border: none;
    background-color: var(--white);
    cursor: pointer;
    border-radius: var(--radius);
    font-size: 14px;
    font-weight: 500;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

button:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

button:active {
    transform: translateY(0);
}

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

input[type="text"], input[type="password"] {
    padding: 11px 14px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    font-size: 14px;
    transition: all 0.2s ease;
    background: var(--white);
    font-family: inherit;
}

input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

/* --- 1. หน้าเข้าสู่ระบบ --- */
#login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.login-box {
    background: var(--white);
    padding: 2.5rem;
    border-radius: var(--radius-lg);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    text-align: center;
    width: 420px;
    animation: fadeIn 0.3s ease;
}

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

.login-box h2 {
    margin-top: 0;
    margin-bottom: 0.5rem;
    font-size: 1.75rem;
    color: var(--text-color);
    font-weight: 600;
}

.login-icon {
    font-size: 3.5rem;
    margin-bottom: 1rem;
    filter: grayscale(0.2);
}

.login-subtitle {
    color: var(--text-muted);
    margin-bottom: 2rem;
    font-size: 0.9rem;
    line-height: 1.5;
}

.login-box input {
    width: 100%;
    margin-bottom: 1.25rem;
}

.login-box button {
    width: 100%;
    background: var(--primary-color);
    color: var(--white);
    font-size: 15px;
    font-weight: 500;
    padding: 12px;
    border: none;
}

.login-box button:hover {
    background: var(--primary-hover);
}

.error-message {
    color: var(--danger-color);
    font-size: 0.875rem;
    margin-top: 1rem;
    padding: 10px 14px;
    background: rgba(220, 38, 38, 0.1);
    border-radius: var(--radius);
    border-left: 3px solid var(--danger-color);
}

/* --- 2. หน้าจัดการกล่องจดหมาย --- */
#inbox-manager-view {
    display: flex;
    flex-direction: column;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 20px;
}

.search-box-inbox input {
    width: 300px;
    padding: 9px 14px;
    font-size: 14px;
}

.new-inbox-form {
    display: flex;
    align-items: center;
    gap: 8px;
}

#new-inbox-name {
    min-width: 200px;
    font-size: 14px;
}

#domain-suffix {
    color: var(--text-muted);
    font-weight: 500;
    font-size: 14px;
}

#create-inbox-btn {
    background: var(--success-color);
    color: var(--white);
    border: none;
    white-space: nowrap;
}

#create-inbox-btn:hover {
    background: var(--success-hover);
}

.header-controls {
    display: flex;
    align-items: center;
    gap: 16px;
}

#logout-btn {
    background: var(--danger-color);
    color: var(--white);
    border: none;
}

#logout-btn:hover {
    background: var(--danger-hover);
}

#inbox-list-container {
    padding: 2rem;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.inbox-item {
    background: var(--white);
    padding: 1.25rem 1.5rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    margin-bottom: 0.75rem;
    cursor: pointer;
    font-weight: 500;
    font-size: 1rem;
    transition: all 0.2s ease;
    position: relative;
    overflow: hidden;
    display: flex;
    align-items: center;
    gap: 12px;
}

.inbox-icon {
    font-size: 1.5rem;
}

.inbox-address {
    flex: 1;
    color: var(--text-color);
}

.inbox-item-badge {
    margin-left: auto;
    background: var(--primary-color);
    color: var(--white);
    padding: 3px 10px;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 600;
    min-width: 24px;
    text-align: center;
}

.copy-btn {
    padding: 7px 12px;
    background: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    opacity: 0;
}

.inbox-item:hover .copy-btn {
    opacity: 1;
}

.copy-btn:hover {
    background: var(--primary-color);
    color: var(--white);
    border-color: var(--primary-color);
    transform: scale(1.05);
}

.inbox-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 3px;
    background: var(--primary-color);
    transform: scaleY(0);
    transition: transform 0.2s ease;
}

.inbox-item:hover::before {
    transform: scaleY(1);
}

.inbox-item:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-md);
    background: linear-gradient(90deg, var(--primary-light) 0%, var(--white) 100%);
}

/* --- 3. หน้ารายการอีเมล --- */
#email-list-view {
    display: flex;
    height: 100vh;
}

#email-list-container {
    width: 400px;
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    background-color: var(--white);
    flex-shrink: 0;
}

#email-list-container header {
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    gap: 12px;
    height: auto;
    padding: 1.25rem 1.5rem;
    position: sticky;
    top: 0;
    z-index: 10;
    background: var(--white);
    border-bottom: 1px solid var(--border-color);
}

.search-box {
    width: 100%;
}

.search-box input {
    width: 100%;
    font-size: 14px;
    padding: 9px 14px;
}

#refresh-emails-btn {
    background: var(--primary-color);
    color: var(--white);
    border: none;
    font-size: 0.875rem;
    padding: 9px 14px;
    align-self: stretch;
    font-weight: 500;
}

#refresh-emails-btn:hover {
    background: var(--primary-hover);
}

#refresh-emails-btn span {
    display: inline-block;
    transition: transform 0.5s cubic-bezier(0.25, 1, 0.5, 1);
}

#refresh-emails-btn:active span {
    transform: rotate(360deg);
}

#back-to-inboxes-btn {
    background: var(--background-color);
    color: var(--text-color);
    font-weight: 500;
    border: 1px solid var(--border-color);
    align-self: stretch;
}

#back-to-inboxes-btn:hover {
    background: var(--white);
    border-color: var(--primary-color);
}

#email-list {
    overflow-y: auto;
    flex-grow: 1;
}

#current-inbox-address {
    word-break: break-all;
    font-size: 1.05rem;
    color: var(--text-color);
    font-weight: 600;
}

.email-item {
    padding: 1.125rem 1.25rem;
    border-bottom: 1px solid var(--border-color);
    cursor: pointer;
    user-select: none;
    transition: all 0.15s ease;
    position: relative;
}

.email-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 3px;
    background: var(--primary-color);
    transform: scaleX(0);
    transition: transform 0.2s ease;
}

.email-item:hover {
    background-color: var(--background-color);
}

.email-item:hover::before {
    transform: scaleX(1);
}

.email-item.active {
    background: var(--primary-light);
    border-left: 3px solid var(--primary-color);
}

.email-item.unread {
    background: linear-gradient(90deg, rgba(37, 99, 235, 0.04) 0%, var(--white) 100%);
}

.email-item.unread strong {
    font-weight: 600;
}

.email-item.unread::after {
    content: '●';
    color: var(--primary-color);
    position: absolute;
    right: 15px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 10px;
}

.email-item strong, .email-item .subject {
    display: block;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    margin-bottom: 6px;
}

.email-item strong {
    font-weight: 600;
    color: var(--text-color);
    font-size: 0.9rem;
}

.email-item .subject {
    color: var(--text-muted);
    font-size: 0.875rem;
    font-weight: 400;
}

.email-item .details {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin: 0;
    font-weight: 400;
}

#email-viewer {
    flex-grow: 1;
    height: 100vh;
    display: flex;
    flex-direction: column;
    background: var(--background-color);
}

.placeholder {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-grow: 1;
    text-align: center;
}

.placeholder-content {
    animation: fadeIn 0.5s ease;
}

.placeholder-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
    opacity: 0.4;
}

.placeholder-content p {
    color: var(--text-color);
    font-size: 1.2rem;
    font-weight: 500;
    margin: 0 0 0.5rem 0;
}

.placeholder-hint {
    color: var(--text-muted);
    font-size: 0.9rem;
}

#email-content-frame {
    width: 100%;
    height: 100%;
    border: none;
    flex-grow: 1;
    background: var(--white);
}

.loading {
    text-align: center;
    padding: 2rem;
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* --- ปุ่มลบ --- */
.delete-btn {
    padding: 7px 10px;
    background: transparent;
    border: none;
    cursor: pointer;
    font-size: 1.1rem;
    opacity: 0.5;
    transition: all 0.2s ease;
    border-radius: 6px;
    line-height: 1;
}

.delete-btn:hover {
    opacity: 1;
    background-color: #FEE2E2;
    color: var(--danger-color);
    transform: scale(1.1);
    box-shadow: none;
}

.inbox-item .delete-btn,
.email-item .delete-btn {
    opacity: 0;
    visibility: hidden;
}

.inbox-item:hover .delete-btn,
.email-item:hover .delete-btn {
    opacity: 1;
    visibility: visible;
}

.email-item .delete-btn {
    position: absolute;
    top: 50%;
    right: 15px;
    transform: translateY(-50%);
    background: var(--white);
}

/* --- Empty States --- */
.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    color: var(--text-muted);
}

.empty-icon {
    font-size: 5rem;
    margin-bottom: 1.5rem;
    opacity: 0.4;
}

.empty-state p {
    font-size: 1.2rem;
    font-weight: 500;
    margin: 0 0 0.5rem 0;
    color: var(--text-color);
}

.empty-hint {
    font-size: 0.95rem;
    color: var(--text-muted);
}

.empty-state-small {
    text-align: center;
    padding: 3rem 1.5rem;
    color: var(--text-muted);
}

.empty-icon-small {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    opacity: 0.4;
}

.empty-state-small p {
    font-size: 1.05rem;
    font-weight: 500;
    margin: 0 0 0.3rem 0;
    color: var(--text-color);
}

.empty-hint-small {
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* --- Notifications --- */
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 14px 20px;
    border-radius: var(--radius);
    font-weight: 500;
    font-size: 0.9rem;
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    opacity: 0;
    transform: translateY(-20px);
    transition: all 0.3s ease;
    max-width: 400px;
}

.notification.show {
    opacity: 1;
    transform: translateY(0);
}

.notification-success {
    background: var(--success-color);
    color: var(--white);
}

.notification-error {
    background: var(--danger-color);
    color: var(--white);
}

.notification-info {
    background: var(--primary-color);
    color: var(--white);
}

/* --- Keyboard Hints --- */
.keyboard-hints {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(0, 0, 0, 0.85);
    backdrop-filter: blur(10px);
    color: var(--white);
    padding: 10px 18px;
    border-radius: 20px;
    font-size: 0.8rem;
    z-index: 100;
    box-shadow: var(--shadow-lg);
}

.keyboard-hints kbd {
    background: rgba(255, 255, 255, 0.2);
    padding: 3px 7px;
    border-radius: 4px;
    font-family: monospace;
    font-weight: 600;
    margin: 0 2px;
}

/* --- Scrollbar --- */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--background-color);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

#email-list::-webkit-scrollbar {
    width: 6px;
}

#email-list::-webkit-scrollbar-track {
    background: transparent;
}

#email-list::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

#email-list::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* --- Animations --- */
@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.loading {
    animation: pulse 1.5s ease-in-out infinite;
}

/* --- Responsive --- */
@media (max-width: 768px) {
    #email-list-view {
        flex-direction: column;
    }
    
    #email-list-container {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
        max-height: 50vh;
    }
    
    header {
        padding: 0 1rem;
        height: auto;
        min-height: var(--header-height);
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
        padding-top: 1rem;
        padding-bottom: 1rem;
    }
    
    .header-left {
        width: 100%;
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .search-box-inbox input {
        width: 100%;
    }
    
    header h1, header h2 {
        font-size: 1.2rem;
    }
    
    .header-controls {
        flex-direction: column;
        width: 100%;
        gap: 8px;
    }
    
    .new-inbox-form {
        width: 100%;
        flex-wrap: wrap;
    }
    
    #new-inbox-name {
        flex: 1;
        min-width: 120px;
    }
    
    #domain-suffix {
        font-size: 0.8rem;
    }
    
    .inbox-item {
        font-size: 0.95rem;
        padding: 1rem;
    }
    
    .copy-btn {
        opacity: 1;
        font-size: 0.75rem;
        padding: 6px 10px;
    }
    
    .login-box {
        width: 90%;
        max-width: 420px;
        padding: 2rem;
    }
    
    .keyboard-hints {
        display: none;
    }
    
    #inbox-list-container {
        padding: 1.25rem;
    }
    
    .email-item {
        padding: 1rem;
    }
    
    .email-item strong {
        font-size: 0.875rem;
    }
    
    .notification {
        right: 10px;
        left: 10px;
        top: 10px;
        max-width: none;
    }
}