/* ============================================================
   轻松传 — 视觉重设计 v2
   渐变导向配色 + 深色模式 + 页面过渡动画 + 微交互
   ============================================================ */

/* ===== CSS 自定义属性（设计令牌） ===== */
:root {
    /* Primary gradient palette */
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #e0e7ff;
    --primary-gradient: linear-gradient(135deg, #6366f1, #8b5cf6);
    --primary-gradient-hover: linear-gradient(135deg, #4f46e5, #7c3aed);

    /* Secondary accent */
    --secondary: #8b5cf6;
    --secondary-light: #ede9fe;

    /* Surfaces */
    --bg: #f0f2f8;
    --bg-gradient: linear-gradient(170deg, #eef1fa 0%, #e4e8f5 40%, #dfe3f0 100%);
    --surface: #ffffff;
    --surface-elevated: #ffffff;

    /* Text */
    --text: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;

    /* Borders & Shadows */
    --border: rgba(99, 102, 241, 0.1);
    --border-focus: rgba(99, 102, 241, 0.4);
    --shadow: 0 4px 24px rgba(99, 102, 241, 0.08), 0 1px 4px rgba(0, 0, 0, 0.04);
    --shadow-lg: 0 12px 48px rgba(99, 102, 241, 0.12), 0 4px 12px rgba(0, 0, 0, 0.05);
    --shadow-glow: 0 0 24px rgba(99, 102, 241, 0.15);

    /* Status */
    --success: #22c55e;
    --success-gradient: linear-gradient(135deg, #22c55e, #16a34a);
    --warning: #f59e0b;
    --error: #ef4444;
    --error-gradient: linear-gradient(135deg, #ef4444, #dc2626);

    /* Shape */
    --radius: 20px;
    --radius-sm: 12px;
    --radius-xs: 8px;

    /* Motion */
    --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
    --view-duration: 0.4s;

    /* Glass */
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.4);
    --glass-blur: 16px;
}

/* ===== 深色模式 ===== */
[data-theme="dark"] {
    --bg: #0f1119;
    --bg-gradient: linear-gradient(170deg, #0f1119 0%, #161826 40%, #1a1d30 100%);
    --surface: #1a1d2e;
    --surface-elevated: #222640;
    --text: #e2e8f0;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --border: rgba(139, 92, 246, 0.15);
    --border-focus: rgba(139, 92, 246, 0.5);
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.3), 0 1px 4px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 12px 48px rgba(0, 0, 0, 0.4), 0 4px 12px rgba(0, 0, 0, 0.25);
    --shadow-glow: 0 0 24px rgba(99, 102, 241, 0.2);
    --primary-light: rgba(99, 102, 241, 0.15);
    --secondary-light: rgba(139, 92, 246, 0.15);
    --glass-bg: rgba(26, 29, 46, 0.75);
    --glass-border: rgba(139, 92, 246, 0.2);
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        --bg: #0f1119;
        --bg-gradient: linear-gradient(170deg, #0f1119 0%, #161826 40%, #1a1d30 100%);
        --surface: #1a1d2e;
        --surface-elevated: #222640;
        --text: #e2e8f0;
        --text-secondary: #94a3b8;
        --text-muted: #64748b;
        --border: rgba(139, 92, 246, 0.15);
        --border-focus: rgba(139, 92, 246, 0.5);
        --shadow: 0 4px 24px rgba(0, 0, 0, 0.3), 0 1px 4px rgba(0, 0, 0, 0.2);
        --shadow-lg: 0 12px 48px rgba(0, 0, 0, 0.4), 0 4px 12px rgba(0, 0, 0, 0.25);
        --shadow-glow: 0 0 24px rgba(99, 102, 241, 0.2);
        --primary-light: rgba(99, 102, 241, 0.15);
        --secondary-light: rgba(139, 92, 246, 0.15);
        --glass-bg: rgba(26, 29, 46, 0.75);
        --glass-border: rgba(139, 92, 246, 0.2);
    }
}

/* ===== Reset ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }
html { font-size: 16px; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", Roboto, "Noto Sans SC", sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

/* ===== 全局渐变背景 + 装饰光晕 ===== */
body::before {
    content: '';
    position: fixed;
    top: -30%;
    left: -20%;
    width: 70%;
    height: 70%;
    background: radial-gradient(ellipse, rgba(99, 102, 241, 0.08) 0%, transparent 70%);
    pointer-events: none;
    z-index: 0;
}

body::after {
    content: '';
    position: fixed;
    bottom: -20%;
    right: -20%;
    width: 60%;
    height: 60%;
    background: radial-gradient(ellipse, rgba(139, 92, 246, 0.06) 0%, transparent 70%);
    pointer-events: none;
    z-index: 0;
}

.app {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    position: relative;
    z-index: 1;
    background: var(--bg-gradient);
}

/* ===== Header — 毛玻璃+渐变 ===== */
.header {
    background: var(--glass-bg);
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    border-bottom: 1px solid var(--glass-border);
    padding: 24px 32px;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-inner {
    max-width: 1100px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: 16px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text);
    letter-spacing: -0.5px;
}

.logo svg {
    color: var(--primary);
    filter: drop-shadow(0 0 8px rgba(99, 102, 241, 0.3));
}

.tagline {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-left: auto;
}

/* ===== Main ===== */
.main {
    flex: 1;
    max-width: 1100px;
    width: 100%;
    margin: 0 auto;
    padding: 48px 32px;
    position: relative;
}

/* ===== Views — CSS 过渡动画 ===== */
.view {
    display: none;
    opacity: 0;
    visibility: hidden;
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    pointer-events: none;
}

.view.active {
    display: block;
    opacity: 1;
    visibility: visible;
    position: relative;
    pointer-events: auto;
    animation: viewEnter var(--view-duration) cubic-bezier(0.22, 1, 0.36, 1) forwards;
}

.view.view-exit {
    display: block;
    opacity: 0;
    visibility: hidden;
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    pointer-events: none;
    animation: viewExit var(--view-duration) cubic-bezier(0.22, 1, 0.36, 1) forwards;
}

.view.view-enter {
    display: block;
    opacity: 0;
    visibility: visible;
    position: relative;
    pointer-events: auto;
    animation: viewEnter var(--view-duration) cubic-bezier(0.22, 1, 0.36, 1) forwards;
}

@keyframes viewEnter {
    from {
        opacity: 0;
        transform: translateY(20px) scale(0.98);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

@keyframes viewExit {
    from {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
    to {
        opacity: 0;
        transform: translateY(-12px) scale(0.98);
    }
}

/* ===== Cards Grid ===== */
.cards {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
}

.card {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 40px 36px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    gap: 20px;
    transition: transform var(--transition), box-shadow var(--transition);
    position: relative;
    overflow: hidden;
}

/* Card gradient border overlay */
.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--primary-gradient);
    opacity: 0;
    transition: opacity var(--transition);
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.card:hover::before {
    opacity: 1;
}

.card-icon {
    color: var(--primary);
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    filter: none;
}

/* Fix SVG icons inside card-icon — SVGs use stroke, not fill with background-clip */
.card-icon svg {
    stroke: url(#iconGradient);
    color: var(--primary);
    filter: drop-shadow(0 0 6px rgba(99, 102, 241, 0.25));
}

.card h2 {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--text);
}

/* ===== Tabs ===== */
.tab-bar {
    display: flex;
    background: var(--bg);
    border-radius: var(--radius-sm);
    padding: 4px;
    border: 1px solid var(--border);
}

.tab {
    flex: 1;
    padding: 10px 24px;
    border: none;
    border-radius: var(--radius-xs);
    background: transparent;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-secondary);
    transition: all var(--transition);
}

.tab.active {
    background: var(--surface);
    color: var(--primary);
    box-shadow: 0 2px 8px rgba(99, 102, 241, 0.12);
}

/* ===== File Drop Zone — 渐变边框 ===== */
.file-drop-zone {
    border: 2px dashed var(--border);
    border-radius: var(--radius-sm);
    padding: 48px 24px;
    text-align: center;
    color: var(--text-secondary);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    transition: all var(--transition);
    cursor: pointer;
    position: relative;
    background: transparent;
}

.file-drop-zone:hover {
    border-color: var(--primary);
    background: var(--primary-light);
}

.file-drop-zone.drag-over {
    border-color: var(--primary);
    background: var(--primary-light);
    border-style: solid;
    box-shadow: var(--shadow-glow);
    animation: dragPulse 1s ease infinite;
}

@keyframes dragPulse {
    0%, 100% { box-shadow: var(--shadow-glow); }
    50% { box-shadow: 0 0 32px rgba(99, 102, 241, 0.25); }
}

.drop-or {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.btn-select {
    display: inline-block;
    padding: 10px 28px;
    background: var(--primary-light);
    color: var(--primary);
    border-radius: 10px;
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all var(--transition);
}

.btn-select:hover {
    background: var(--primary-gradient);
    color: #fff;
    transform: translateY(-1px);
}

/* ===== File Preview ===== */
.file-preview {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 16px 20px;
    background: var(--primary-light);
    border-radius: var(--radius-sm);
    color: var(--primary);
}

.file-preview svg { flex-shrink: 0; }

.file-preview-info {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 2px;
    min-width: 0;
}

.file-preview-name {
    font-weight: 600;
    font-size: 0.95rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.file-preview-size { font-size: 0.8rem; opacity: 0.8; }

.file-preview-remove {
    width: 36px;
    height: 36px;
    border: none;
    background: transparent;
    color: var(--primary);
    font-size: 1.3rem;
    cursor: pointer;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
    /* Ensure minimum touch target */
    min-width: 36px;
    min-height: 36px;
}

.file-preview-remove:hover {
    background: rgba(99, 102, 241, 0.15);
    transform: rotate(90deg);
}

/* ===== Textarea ===== */
textarea {
    width: 100%;
    min-height: 120px;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 16px;
    font-size: 16px; /* ≥16px prevents iOS Safari auto-zoom */
    font-family: inherit;
    resize: vertical;
    transition: border-color var(--transition), box-shadow var(--transition);
    line-height: 1.6;
    background: var(--surface);
    color: var(--text);
}

textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
}

/* ===== Receive Input ===== */
.form-group { margin-bottom: 4px; }
.form-group label {
    display: block;
    margin-bottom: 10px;
    font-size: 0.95rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.code-input-wrap { position: relative; }

input[type="text"] {
    width: 100%;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 16px;
    font-size: 2rem;
    text-align: center;
    letter-spacing: 16px;
    font-weight: 700;
    color: var(--text);
    transition: border-color var(--transition), box-shadow var(--transition), background var(--transition);
    background: var(--bg);
}

input[type="text"]:focus {
    outline: none;
    border-color: var(--primary);
    background: var(--surface);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
}
input[type="text"]::placeholder { color: var(--text-muted); letter-spacing: 12px; }

/* ===== Buttons — 渐变+微交互 ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 32px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    text-align: center;
    text-decoration: none;
    transition: all var(--transition);
    line-height: 1;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: var(--primary-gradient);
    color: #fff;
    box-shadow: 0 4px 16px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
    background: var(--primary-gradient-hover);
    box-shadow: 0 6px 24px rgba(99, 102, 241, 0.4);
    transform: translateY(-2px);
}

.btn-primary:active {
    transform: scale(0.97) translateY(0);
    box-shadow: 0 2px 8px rgba(99, 102, 241, 0.3);
}

/* Ripple / glow pseudo-element for primary buttons */
.btn-primary::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at var(--ripple-x, 50%) var(--ripple-y, 50%), rgba(255,255,255,0.25) 0%, transparent 60%);
    opacity: 0;
    transition: opacity 0.3s;
}

.btn-primary:active::after {
    opacity: 1;
}

.btn-ghost {
    background: transparent;
    color: var(--text-secondary);
    padding: 12px 24px;
}

.btn-ghost:hover {
    color: var(--error);
    background: rgba(239, 68, 68, 0.06);
}

.panel-actions {
    display: flex;
    gap: 12px;
    padding: 20px 36px;
    border-top: 1px solid var(--border);
}

.panel-actions .btn-ghost {
    flex: 1;
    padding: 12px 20px;
}

.btn-danger { color: var(--error); }
.btn-danger:hover {
    background: rgba(239, 68, 68, 0.06);
}

.btn-lg {
    width: 100%;
    padding: 18px 32px;
    font-size: 1.1rem;
    border-radius: 14px;
}

/* ===== Panel (Sender/Receiver View) — 毛玻璃+渐变 ===== */
.panel {
    max-width: 640px;
    margin: 0 auto;
    background: var(--surface);
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border);
    overflow: hidden;
    position: relative;
}

/* Panel accent gradient bar at top */
.panel::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--primary-gradient);
}

.panel-header {
    padding: 40px 36px 28px;
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    border-bottom: 1px solid var(--border);
    background: var(--glass-bg);
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    position: relative;
}

.panel-header.center {
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 16px;
}

.panel-title {
    font-size: 1.4rem;
    font-weight: 700;
}

.panel-body { padding: 28px 36px; }

/* ===== Code Display — 渐变文字 ===== */
.code-display {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.code-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 1px;
    font-weight: 600;
}

.code-value {
    font-size: 3.5rem;
    font-weight: 900;
    letter-spacing: 14px;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    font-variant-numeric: tabular-nums;
}

.code-hint { font-size: 0.85rem; color: var(--text-muted); }

.copy-btn {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 10px;
    cursor: pointer;
    color: var(--text-secondary);
    transition: all var(--transition);
    flex-shrink: 0;
    margin-top: 8px;
}

.copy-btn:hover {
    background: var(--primary-light);
    color: var(--primary);
    transform: scale(1.1);
}

/* ===== Status ===== */
.status-row {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 20px;
}

.status-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--text-muted);
    flex-shrink: 0;
    transition: background var(--transition);
}

.status-dot.connecting {
    background: var(--warning);
    animation: pulse 1.5s infinite, statusGlow 2s infinite;
}

.status-dot.online {
    background: var(--success);
    box-shadow: 0 0 8px rgba(34, 197, 94, 0.4);
}

.status-dot.done {
    background: var(--primary);
    box-shadow: 0 0 8px rgba(99, 102, 241, 0.4);
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.4; }
}

@keyframes statusGlow {
    0%, 100% { box-shadow: 0 0 4px rgba(245, 158, 11, 0.3); }
    50% { box-shadow: 0 0 12px rgba(245, 158, 11, 0.5); }
}

.status-text { font-size: 1rem; color: var(--text-secondary); }

/* ===== Transfer Progress — 渐变+shimmer ===== */
.transfer-panel { margin-bottom: 8px; }

.transfer-file-info {
    font-size: 0.95rem;
    color: var(--text);
    font-weight: 500;
    margin-bottom: 12px;
}

.progress-bar {
    width: 100%;
    height: 10px;
    background: var(--bg);
    border-radius: 5px;
    overflow: hidden;
    margin-bottom: 10px;
    position: relative;
}

.progress-fill {
    height: 100%;
    background: var(--primary-gradient);
    border-radius: 5px;
    width: 0%;
    transition: width 0.3s ease;
    position: relative;
    overflow: hidden;
}

/* Shimmer sweep effect */
.progress-fill::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% { left: -100%; }
    100% { left: 100%; }
}

.progress-stats {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-variant-numeric: tabular-nums;
}

/* ===== Received Text ===== */
.received-text-wrap { margin-bottom: 16px; }

.received-text {
    background: var(--bg);
    padding: 20px;
    border-radius: var(--radius-sm);
    text-align: left;
    white-space: pre-wrap;
    word-break: break-all;
    max-height: 320px;
    overflow-y: auto;
    font-size: 0.95rem;
    line-height: 1.6;
    border: 1px solid var(--border);
    color: var(--text);
}

/* ===== Done View ===== */
.center-panel {
    text-align: center;
    padding: 60px 36px;
}

.done-icon { margin-bottom: 20px; }

.done-icon svg {
    filter: drop-shadow(0 0 16px rgba(34, 197, 94, 0.3));
}

.done-title {
    font-size: 1.8rem;
    font-weight: 800;
    background: var(--success-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 8px;
}

.done-subtitle {
    color: var(--text-secondary);
    margin-bottom: 28px;
    font-size: 1rem;
}

/* ===== Pulse Icon — 增强脉冲 ===== */
.pulse-icon {
    color: var(--primary);
    animation: pulse 2s infinite, iconFloat 3s ease-in-out infinite;
}

@keyframes iconFloat {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-6px); }
}

/* ===== Toast — 毛玻璃+左边框accent ===== */
.toast-container {
    position: fixed;
    top: 24px;
    right: 24px;
    z-index: 9999;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.toast {
    padding: 14px 24px;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 500;
    color: #fff;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    animation: toastSlideIn var(--transition-bounce) forwards;
    max-width: 360px;
    border-left: 4px solid transparent;
}

.toast-info {
    background: rgba(99, 102, 241, 0.9);
    border-left-color: rgba(255, 255, 255, 0.5);
}

.toast-error {
    background: rgba(239, 68, 68, 0.9);
    border-left-color: rgba(255, 255, 255, 0.5);
}

.toast-warn {
    background: rgba(245, 158, 11, 0.9);
    color: var(--text);
    border-left-color: rgba(0, 0, 0, 0.15);
}

.toast.fade-out {
    opacity: 0;
    transform: translateX(30px);
    transition: all 0.3s ease;
}

@keyframes toastSlideIn {
    from {
        transform: translateX(100%) scale(0.9);
        opacity: 0;
    }
    60% {
        transform: translateX(-8px) scale(1.02);
    }
    to {
        transform: translateX(0) scale(1);
        opacity: 1;
    }
}

/* ===== Footer ===== */
.footer {
    text-align: center;
    padding: 24px 32px;
    color: var(--text-muted);
    font-size: 0.85rem;
    border-top: 1px solid var(--border);
    background: var(--glass-bg);
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
}

/* ===== Hidden ===== */
.hidden { display: none !important; }

/* ===== Theme Toggle ===== */
.theme-toggle {
    width: 40px;
    height: 40px;
    border: 1px solid var(--glass-border);
    border-radius: 50%;
    background: var(--glass-bg);
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
    flex-shrink: 0;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}

.theme-toggle:hover {
    background: var(--primary-light);
    color: var(--primary);
    transform: scale(1.1);
}

[data-theme="dark"] .icon-sun { display: none; }
:root:not([data-theme="dark"]) .icon-moon { display: none; }

/* ===== WebRTC Banner ===== */
.webrtc-banner {
    width: 100%;
    padding: 14px 24px;
    background: linear-gradient(135deg, #fbbf24, #f59e0b);
    color: #1e293b;
    text-align: center;
    font-weight: 600;
    font-size: 0.95rem;
    border-radius: var(--radius-sm);
    margin-bottom: 20px;
}

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

/* --- 1024px: Tablet landscape / small desktop --- */
@media (max-width: 1024px) {
    .main { padding: 36px 24px; }
    .cards { gap: 24px; }
}

/* --- 768px: Tablet portrait --- */
@media (max-width: 768px) {
    .header { padding: 16px 20px; }
    .header-inner { flex-direction: column; gap: 4px; text-align: center; }
    .tagline { margin-left: 0; font-size: 0.85rem; }

    .main { padding: 24px 16px; }

    .cards { grid-template-columns: 1fr; gap: 20px; }
    .card { padding: 28px 24px; }
    .card:hover { transform: translateY(-2px); }

    .code-value { font-size: 2.5rem; letter-spacing: 10px; }

    .panel-header { padding: 28px 24px 20px; }
    .panel-body { padding: 20px 24px; }
    .panel-actions { padding: 16px 24px; }

    .center-panel { padding: 40px 24px; }

    input[type="text"] { font-size: 1.5rem; letter-spacing: 12px; padding: 14px; }

    .toast-container { top: 12px; right: 12px; left: 12px; }
    .toast { max-width: 100%; }

    /* Ensure touch targets ≥44px */
    .copy-btn { width: 44px; height: 44px; }
    .tab { min-height: 44px; display: flex; align-items: center; justify-content: center; }
    .file-preview-remove { width: 36px; height: 36px; }
}

/* --- 480px: Large phone --- */
@media (max-width: 480px) {
    .cards { gap: 16px; }
    .card { padding: 24px 20px; gap: 16px; }
    .card:hover { transform: none; }
    .card h2 { font-size: 1.3rem; }

    .btn-lg { padding: 16px 24px; font-size: 1rem; }

    /* Touch targets ≥44px for all interactive elements */
    .btn { min-height: 44px; }
    .btn-select { min-height: 44px; display: inline-flex; align-items: center; justify-content: center; }
    .tab { min-height: 44px; }
    .copy-btn { width: 44px; height: 44px; }
    .file-preview-remove { width: 44px; height: 44px; font-size: 1.5rem; }

    .code-value { font-size: 2rem; letter-spacing: 8px; }

    .file-drop-zone { padding: 32px 16px; }

    .panel-actions { padding: 16px 20px; gap: 8px; }
    .panel-actions .btn-ghost { min-height: 44px; padding: 12px 16px; }

    /* Progress bar slightly taller for touch */
    .progress-bar { height: 12px; }
    .progress-stats { font-size: 0.8rem; }

    /* Smaller heading in done view */
    .done-title { font-size: 1.5rem; }
    .done-subtitle { font-size: 0.9rem; }

    /* Footer compact */
    .footer { padding: 16px 20px; font-size: 0.8rem; }

    /* Ensure textarea/input font-size ≥16px to prevent iOS Safari zoom */
    textarea { font-size: 16px; }
    input[type="text"] { font-size: 24px; }

    /* Code input wrap — keep comfortable tap target */
    .code-input-wrap input[type="text"] { padding: 16px; }
}

/* --- 375px: Small phone --- */
@media (max-width: 375px) {
    .main { padding: 16px 12px; }
    .card { padding: 20px 16px; gap: 14px; }
    .card h2 { font-size: 1.2rem; }

    .header { padding: 12px 16px; }
    .logo { font-size: 1.25rem; gap: 8px; }
    .logo svg { width: 26px; height: 26px; }

    .code-value { font-size: 1.8rem; letter-spacing: 6px; }
    .code-hint { font-size: 0.75rem; }

    .panel-header { padding: 24px 16px 16px; }
    .panel-body { padding: 16px; }
    .panel-actions { padding: 12px 16px; gap: 8px; }

    .center-panel { padding: 32px 16px; }
    .done-title { font-size: 1.3rem; }
    .done-icon svg { width: 48px; height: 48px; }

    .file-drop-zone { padding: 24px 12px; }
    .btn-lg { padding: 14px 20px; font-size: 0.95rem; border-radius: 10px; }

    .status-text { font-size: 0.9rem; }
    .progress-stats { font-size: 0.75rem; }

    /* Receiver cancel button full width for easy tap */
    #receiver-cancel { width: 100%; min-height: 44px; padding: 14px 16px; }
}