:root {
    --bg-color: #000000;
    --card-bg: #0a0a0a;
    --primary: #ededed;
    --primary-hover: #ffffff;
    --accent: #ffffff;
    --text-main: #ededed;
    --text-muted: #888888;
    --border-color: #333333;
    --focus-ring: rgba(255, 255, 255, 0.15);
    --bg-gradient: #1a1a1a;
    --btn-text: #000000;
    --paste-hover-bg: rgba(255, 255, 255, 0.02);
    --delete-bg: rgba(0, 0, 0, 0.6);
    --card-glow: rgba(255, 255, 255, 0.2);
    --card-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
}

[data-theme="light"] {
    --bg-color: #fafafa;
    --card-bg: #ffffff;
    --primary: #111111;
    --primary-hover: #000000;
    --accent: #000000;
    --text-main: #111111;
    --text-muted: #666666;
    --border-color: #eaeaea;
    --focus-ring: rgba(0, 0, 0, 0.1);
    --bg-gradient: #ebebeb;
    --btn-text: #ffffff;
    --paste-hover-bg: rgba(0, 0, 0, 0.03);
    --delete-bg: rgba(255, 255, 255, 0.8);
    --card-glow: rgba(0, 0, 0, 0.05);
    --card-shadow: 0 12px 40px rgba(0, 0, 0, 0.08);
}

* {
    box-sizing: border-box;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    background-color: var(--bg-color);
    background-image: radial-gradient(circle at 50% -20%, var(--bg-gradient) 0%, transparent 40%);
    color: var(--text-main);
    margin: 0;
    padding: 40px 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
}

.logo-container {
    text-align: center;
    margin-bottom: 40px;
    animation: fadeInDown 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.app-icon {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 10px;
}

.logo {
    color: var(--text-main);
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: -0.03em;
    margin: 0;
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo svg {
    stroke: var(--text-main);
    width: 28px;
    height: 28px;
}

.logo-sub {
    color: var(--text-muted);
    font-weight: 500;
    font-size: 0.7rem;
    margin-top: 6px;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.main-card {
    background: var(--card-bg);
    width: 100%;
    max-width: 480px;
    border-radius: 12px;
    box-shadow: 0 0 0 1px var(--border-color), var(--card-shadow);
    animation: fadeInUp 0.6s cubic-bezier(0.16, 1, 0.3, 1);
    position: relative;
    overflow: hidden;
}

.main-card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--card-glow), transparent);
    z-index: 10;
}

.tabs {
    display: flex;
    gap: 4px;
    background: var(--bg-color);
    border-radius: 8px;
    padding: 4px;
    margin: 24px 24px 0 24px;
    border: 1px solid var(--border-color);
}

.tab-btn {
    flex: 1;
    padding: 10px;
    background: transparent;
    color: var(--text-muted);
    border: none;
    cursor: pointer;
    font-size: 0.875rem;
    font-weight: 500;
    border-radius: 6px;
    transition: all 0.2s ease;
}

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

.tab-btn.active {
    color: var(--text-main);
    background: rgba(255, 255, 255, 0.1);
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

[data-theme="light"] .tab-btn.active {
    background: #ffffff;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.form-section {
    padding: 24px;
    display: none;
    animation: fadeIn 0.3s ease;
    flex-direction: column;
    gap: 20px;
}

.form-section.active {
    display: flex;
}

.input-row {
    display: flex;
    gap: 16px;
}

.input-group {
    flex: 1;
    display: flex;
    flex-direction: column;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-muted);
    font-size: 0.85rem;
}

input[type="text"],
textarea,
select {
    width: 100%;
    padding: 10px 12px;
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-main);
    border-radius: 6px;
    outline: none;
    font-size: 0.875rem;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

textarea {
    resize: vertical;
    min-height: 100px;
    line-height: 1.5;
}

input:focus,
textarea:focus,
select:focus {
    border-color: var(--text-muted);
    box-shadow: 0 0 0 1px var(--text-muted);
}

select option {
    background-color: var(--card-bg);
    color: var(--text-main);
}

.action-btn {
    width: 100%;
    padding: 12px;
    background: var(--text-main);
    color: var(--btn-text);
    border: 1px solid var(--text-main);
    border-radius: 6px;
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    margin-top: 8px;
}

.action-btn:hover {
    background: transparent;
    color: var(--text-main);
}

.action-btn:active {
    transform: scale(0.98);
}

.result-box {
    margin-top: 24px;
    padding: 16px;
    background: transparent;
    border: 1px dashed var(--border-color);
    border-radius: 6px;
    display: none;
    word-break: break-all;
    animation: slideUp 0.3s ease;
}

.pin-display {
    font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
    font-size: 2.2rem;
    color: var(--text-main);
    text-align: center;
    font-weight: 700;
    letter-spacing: 0.25em;
    margin: 16px 0;
    text-shadow: 0 0 20px rgba(255,255,255,0.15);
}

/* KHU VỰC PASTE VÀ THUMBNAIL */
.paste-zone {
    border: 1px dashed var(--border-color);
    padding: 24px;
    text-align: center;
    background: transparent;
    color: var(--text-muted);
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s ease;
    min-height: 120px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.paste-zone:hover {
    border-color: var(--text-muted);
    background: var(--paste-hover-bg);
}

.paste-zone b {
    color: var(--text-main);
}

.preview-container {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 16px;
    width: 100%;
    justify-content: center;
}

.preview-item {
    position: relative;
    width: 64px;
    height: 64px;
    border-radius: 6px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    transition: transform 0.2s;
}

.preview-item:hover {
    transform: scale(1.05);
}

.preview-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.delete-btn {
    position: absolute;
    top: 4px;
    right: 4px;
    background-color: var(--delete-bg);
    color: var(--text-main);
    width: 20px;
    height: 20px;
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 10px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.2s ease;
    backdrop-filter: blur(4px);
}

.delete-btn:hover {
    background-color: #ef4444;
}

.preview-count {
    color: var(--text-muted);
    font-weight: 500;
    margin-top: 12px;
    font-size: 0.8rem;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

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

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

@keyframes slideUp {
    from { opacity: 0; transform: translateY(5px); }
    to { opacity: 1; transform: translateY(0); }
}

.theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.2s ease;
    z-index: 100;
}

.theme-toggle:hover {
    color: var(--text-main);
    border-color: var(--text-muted);
    background: var(--paste-hover-bg);
}

/* Toast Notification */
.toast-container {
    position: fixed;
    bottom: 24px;
    right: 24px;
    display: flex;
    flex-direction: column;
    gap: 12px;
    z-index: 9999;
}

.toast {
    background: var(--card-bg);
    color: var(--text-main);
    border: 1px solid var(--border-color);
    padding: 12px 20px;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    font-size: 0.9rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 8px;
    transform: translateX(120%);
    opacity: 0;
    transition: all 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

.toast.show {
    transform: translateX(0);
    opacity: 1;
}

.toast.error {
    border-left: 4px solid #ef4444;
}

.toast.success {
    border-left: 4px solid var(--accent);
}

/* Modal Overlay */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(5px);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    animation: fadeIn 0.3s ease;
}

.modal-overlay.show {
    display: flex;
}

.modal-content {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 32px;
    max-width: 400px;
    width: 90%;
    text-align: center;
    box-shadow: var(--card-shadow);
    animation: slideUp 0.3s ease;
}

.modal-title {
    font-size: 1.25rem;
    font-weight: 800;
    margin-bottom: 8px;
    color: var(--text-main);
    letter-spacing: 0.5px;
}

.modal-desc {
    color: var(--text-muted);
    font-size: 0.875rem;
    margin-bottom: 24px;
    line-height: 1.5;
}

#qrcode-container {
    background: white;
    padding: 16px;
    border-radius: 8px;
    display: inline-block;
    margin: 0 auto 24px auto;
}

.confirm-btn {
    width: 100%;
    padding: 14px;
    background: var(--text-main);
    color: var(--btn-text);
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.confirm-btn:hover {
    opacity: 0.9;
}

.confirm-btn:active {
    transform: scale(0.98);
}

/* Checkbox Styles */
.checkbox-container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    margin-bottom: 20px;
    cursor: pointer;
    font-size: 0.9rem;
    color: var(--text-main);
    user-select: none;
}

.checkbox-container input {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--accent);
}

.confirm-btn:disabled {
    background: var(--border-color);
    color: var(--text-muted);
    cursor: not-allowed;
    opacity: 0.7;
}

/* Delete Data Button */
.delete-data-btn {
    background: transparent;
    color: var(--text-main);
    border: 1px solid var(--border-color);
    margin-top: 20px;
    transition: all 0.2s ease;
}

.delete-data-btn:hover {
    background: #ef4444;
    color: #ffffff;
    border-color: #ef4444;
}

/* Responsive Design for Mobile */
@media (max-width: 600px) {
    body {
        padding: 20px 12px;
    }

    .main-card {
        border-radius: 8px;
    }

    .form-section {
        padding: 16px;
    }

    .paste-zone {
        padding: 16px;
        min-height: 100px;
    }

    .modal-content {
        padding: 24px;
        width: 95%;
    }
}

/* Toggle Switch Styles */
.switch {
  position: relative;
  display: inline-block;
  width: 44px;
  height: 24px;
}

.switch input { 
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--border-color);
  transition: .4s;
}

.slider:before {
  position: absolute;
  content: "";
  height: 18px;
  width: 18px;
  left: 3px;
  bottom: 3px;
  background-color: var(--btn-text);
  transition: .3s;
}

input:checked + .slider {
  background-color: var(--accent);
}

input:focus + .slider {
  box-shadow: 0 0 1px var(--accent);
}

input:checked + .slider:before {
  transform: translateX(20px);
}

.slider.round {
  border-radius: 24px;
}

.slider.round:before {
  border-radius: 50%;
}