:root {
    --bg-primary: #000000;
    --bg-overlay: rgba(0, 0, 0, 0.6);
    --bg-modal: #1a1a1a;
    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.8);
    --text-muted: rgba(255, 255, 255, 0.5);
    --border-color: rgba(255, 255, 255, 0.2);
    --border-active: #ffffff;
    --btn-bg: rgba(255, 255, 255, 0.15);
    --btn-hover: rgba(255, 255, 255, 0.12);
    --btn-active-bg: rgba(255, 255, 255, 0.15);
    --dashed-color: rgba(255, 255, 255, 0.5);
    --modal-overlay: rgba(0, 0, 0, 0.85);
    --shadow-color: rgba(0, 0, 0, 0.8);
    --btn-primary-bg: #ffffff;
    --btn-primary-hover: #e8e8e8;
    --btn-primary-text: #000000;
    --btn-secondary-bg: rgba(255, 255, 255, 0.12);
    --btn-secondary-hover: rgba(255, 255, 255, 0.2);
    --btn-secondary-text: #ffffff;
    --shutter-border: rgba(255, 255, 255, 0.9);
    --shutter-inner-bg: #ffffff;
    --shutter-disabled: rgba(255, 255, 255, 0.5);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 12px;
    --spacing-lg: 20px;
    --spacing-xl: 24px;
    --font-size-sm: 12px;
    --font-size-md: 13px;
    --font-size-lg: 14px;
    --font-size-xl: 15px;
    --shutter-size: 72px;
    --shutter-inner: 56px;
    --border-width: 2px;
    --blur-amount: 10px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
    outline: none;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    height: 100dvh;
    overflow: hidden;
    user-select: none;
}

/* ===== 主容器 ===== */
#app {
    height: 100dvh;
    display: flex;
    flex-direction: column;
    background: var(--bg-primary);
    max-width: 100%;
    margin: 0 auto;
    position: relative;
}

/* ===== 顶部状态栏 ===== */
#topBar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-overlay);
    backdrop-filter: blur(var(--blur-amount));
    z-index: 10;
    flex-shrink: 0;
}

#statusHint {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    font-weight: 400;
    letter-spacing: 0.3px;
}

#cardInfo {
    font-size: var(--font-size-sm);
    color: var(--text-muted);
    background: var(--bg-overlay);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-md);
    white-space: nowrap;
}

/* ===== 预览区域（拍摄+透卡叠加） ===== */
#previewArea {
    flex: 1;
    position: relative;
    background: var(--bg-primary);
    overflow: hidden;
    min-height: 0;
    display: flex;
    align-items: center;
    justify-content: center;
}

#videoContainer {
    position: relative;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

#video {
    width: 100%;
    height: 100%;
    object-fit: cover;
    position: absolute;
    top: 0;
    left: 0;
}

/* ===== 透卡容器 ===== */
#cardContainer {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2;
}

#cardContainer canvas {
    display: block;
    position: relative;
}

/* ===== 虚线边框（标出透卡范围） ===== */
#dashedBorder {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: var(--border-width) dashed var(--dashed-color);
    border-radius: var(--radius-sm);
    pointer-events: none;
    z-index: 3;
}

/* ===== 底部控制栏 ===== */
#bottomBar {
    flex-shrink: 0;
    padding: var(--spacing-md) 0 var(--spacing-xl);
    background: var(--bg-overlay);
    backdrop-filter: blur(var(--blur-amount));
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
}

/* ===== 透卡选择（横向滚动） ===== */
#cardOptionsWrapper {
    width: 100%;
    overflow-x: auto;
    overflow-y: hidden;
    -webkit-overflow-scrolling: touch;
    padding: 0 16px;
    scrollbar-width: none;
}

#cardOptionsWrapper::-webkit-scrollbar {
    display: none;
}

#cardOptions {
    display: flex;
    gap: var(--spacing-sm);
    white-space: nowrap;
    padding: var(--border-width) 0;
}

#cardOptions button {
    padding: 5px 16px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    background: var(--btn-bg);
    color: var(--text-muted);
    font-size: var(--font-size-md);
    cursor: pointer;
    transition: all 0.2s;
    flex-shrink: 0;
    backdrop-filter: blur(var(--spacing-xs));
}

#cardOptions button:hover {
    background: var(--btn-hover);
}

#cardOptions button.active {
    border-color: var(--border-active);
    background: var(--btn-active-bg);
    color: var(--text-primary);
}

/* ===== 快门按钮 ===== */
#shutterArea {
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: var(--border-width);
}

#captureBtn {
    width: var(--shutter-size);
    height: var(--shutter-size);
    border-radius: 50%;
    border: 4px solid var(--shutter-border);
    background: var(--btn-bg);
    cursor: pointer;
    transition: all 0.15s;
    position: relative;
    flex-shrink: 0;
}

#captureBtn::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: var(--shutter-inner);
    height: var(--shutter-inner);
    border-radius: 50%;
    background: var(--shutter-inner-bg);
    transition: all 0.15s;
}

#captureBtn:active::after {
    transform: translate(-50%, -50%) scale(0.85);
}

#captureBtn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

#captureBtn:disabled::after {
    background: var(--shutter-disabled);
}

/* ===== 弹窗 ===== */
.modal-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--modal-overlay);
    z-index: 999;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-lg);
    backdrop-filter: blur(20px);
}

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

.modal-content {
    background: var(--bg-modal);
    border-radius: var(--radius-lg);
    padding: 32px 28px;
    max-width: 400px;
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

.modal-content h2 {
    font-size: 22px;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.modal-content p {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.5;
    text-align: center;
    margin: 0;
}

.modal-content img {
    max-width: 100%;
    max-height: 55dvh;
    display: block;
    border-radius: var(--radius-sm);
    object-fit: contain;
}

.modal-buttons {
    display: flex;
    justify-content: center;
    gap: 12px;
    width: 100%;
}

.modal-buttons button {
    padding: 10px 32px;
    border: none;
    border-radius: var(--radius-xl);
    font-size: var(--font-size-xl);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.15s;
    flex: 1;
}

.modal-buttons button:active {
    transform: scale(0.95);
}

.modal-buttons .btn-primary {
    background: var(--btn-primary-bg);
    color: var(--btn-primary-text);
}

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

.modal-buttons .btn-secondary {
    background: var(--btn-secondary-bg);
    color: var(--btn-secondary-text);
}

.modal-buttons .btn-secondary:hover {
    background: var(--btn-secondary-hover);
}

.modal-buttons .btn-full {
    flex: none;
    width: 100%;
}