/* ==========================================================================
   ĐỌC SÁCH ONLINE — MODERN PREMIUM UI SYSTEM
   Elevated aesthetics, glassmorphism, fluid micro-interactions, rich gradients.
   ========================================================================== */

/* ---- Color Tokens & Elevating Themes ---- */
:root {
    --accent: #f05a46;
    --accent-strong: #d94532;
    --accent-soft: color-mix(in srgb, var(--accent) 12%, transparent);
    --accent-glow: rgba(240, 90, 70, 0.35);

    /* Light Theme (Studio Ivory & Warm Ambient Light) */
    --desk: #f6f2ec;
    --desk-2: #ffffff;
    --paper: #fefdfb;
    --ink: #1f1d1a;
    --muted: #78716a;
    --line: #e8e2d8;
    --chrome: rgba(255, 255, 255, 0.86);
    --chrome-solid: #ffffff;
    --chrome-ink: #2b2622;
    --chrome-border: rgba(40, 30, 20, 0.08);
    --on-desk: #231f1c;
    --muted-desk: #6e675f;

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 18px;
    --radius-full: 9999px;

    --shadow-subtle: 0 4px 16px -2px rgba(40, 30, 20, 0.06);
    --shadow-pill: 0 16px 40px -8px rgba(35, 25, 15, 0.18), 0 0 0 1px rgba(255, 255, 255, 0.6) inset;
    --shadow-pop: 0 24px 50px -12px rgba(35, 25, 15, 0.22), 0 0 0 1px rgba(255, 255, 255, 0.7) inset;
    --shadow-card: 0 16px 48px -12px rgba(45, 30, 20, 0.09), 0 0 0 1px rgba(255, 255, 255, 0.7) inset;

    --glass-blur: blur(20px) saturate(180%);
}

/* Theme: Pure White (Minimalist Clean White) */
:root[data-theme="white"] {
    --desk: #ffffff;
    --desk-2: #ffffff;
    --paper: #ffffff;
    --ink: #111827;
    --muted: #6b7280;
    --line: #e5e7eb;
    --chrome: rgba(255, 255, 255, 0.95);
    --chrome-solid: #ffffff;
    --chrome-ink: #1f2937;
    --chrome-border: rgba(0, 0, 0, 0.08);
    --on-desk: #111827;
    --muted-desk: #4b5563;
    --shadow-pill: 0 16px 40px -8px rgba(0, 0, 0, 0.12), 0 0 0 1px rgba(0, 0, 0, 0.06);
    --shadow-pop: 0 24px 50px -12px rgba(0, 0, 0, 0.16), 0 0 0 1px rgba(0, 0, 0, 0.08);
    --shadow-card: 0 16px 48px -12px rgba(0, 0, 0, 0.08), 0 0 0 1px rgba(0, 0, 0, 0.06);
}

:root[data-theme="white"] .app {
    background: #ffffff !important;
}

:root[data-theme="white"] .app::before {
    display: none !important;
}

/* Theme: Slate (Modern Neutral Slate Gray) */
:root[data-theme="slate"] {
    --desk: #e2e8f0;
    --desk-2: #f8fafc;
    --paper: #ffffff;
    --ink: #0f172a;
    --muted: #64748b;
    --line: #cbd5e1;
    --chrome: rgba(255, 255, 255, 0.92);
    --chrome-solid: #ffffff;
    --chrome-ink: #1e293b;
    --chrome-border: rgba(15, 23, 42, 0.08);
    --on-desk: #0f172a;
    --muted-desk: #475569;
    --shadow-pill: 0 16px 40px -8px rgba(15, 23, 42, 0.14);
    --shadow-pop: 0 24px 50px -12px rgba(15, 23, 42, 0.18);
    --shadow-card: 0 16px 48px -12px rgba(15, 23, 42, 0.08);
}

/* Theme: Wood (Warm Walnut Library Desk) */
:root[data-theme="wood"] {
    --desk: #211915;
    --desk-2: #2e221d;
    --paper: #f8f3ea;
    --ink: #2b2018;
    --muted: #a69888;
    --line: #45342a;
    --chrome: rgba(38, 28, 23, 0.9);
    --chrome-solid: #2c201a;
    --chrome-ink: #f7ede3;
    --chrome-border: rgba(255, 255, 255, 0.09);
    --on-desk: #f7ede3;
    --muted-desk: #bdae9e;
    --shadow-pill: 0 18px 48px -8px rgba(0, 0, 0, 0.75);
    --shadow-pop: 0 24px 54px -12px rgba(0, 0, 0, 0.85);
    --shadow-card: 0 16px 48px -12px rgba(0, 0, 0, 0.6);
}

/* Theme: Sepia (Refined Antique Library) */
:root[data-theme="sepia"] {
    --desk: #dfd3be;
    --desk-2: #ede2cf;
    --paper: #f9f2e3;
    --ink: #3b3020;
    --muted: #827258;
    --line: #d8c8ab;
    --chrome: rgba(246, 238, 222, 0.88);
    --chrome-solid: #f6eedc;
    --chrome-ink: #3d3221;
    --chrome-border: rgba(80, 60, 30, 0.12);
    --on-desk: #382d1c;
    --muted-desk: #74644a;
    --shadow-pill: 0 16px 40px -8px rgba(50, 35, 20, 0.22);
    --shadow-pop: 0 24px 50px -12px rgba(50, 35, 20, 0.26);
    --shadow-card: 0 16px 48px -12px rgba(60, 40, 20, 0.12);
}

/* Theme: Night (Obsidian & Deep Indigo Glow) */
:root[data-theme="night"] {
    --desk: #0e1117;
    --desk-2: #161b24;
    --paper: #f1eee7;
    --ink: #2b2824;
    --muted: #8b949e;
    --line: #30363d;
    --chrome: rgba(22, 27, 36, 0.85);
    --chrome-solid: #161b24;
    --chrome-ink: #f0f6fc;
    --chrome-border: rgba(255, 255, 255, 0.08);
    --on-desk: #f0f6fc;
    --muted-desk: #9ca3af;
    --shadow-pill: 0 18px 48px -8px rgba(0, 0, 0, 0.65), 0 0 0 1px rgba(255, 255, 255, 0.08) inset;
    --shadow-pop: 0 24px 54px -12px rgba(0, 0, 0, 0.75), 0 0 0 1px rgba(255, 255, 255, 0.1) inset;
    --shadow-card: 0 16px 48px -12px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(255, 255, 255, 0.06) inset;
}

/* Accent Variations */
:root[data-accent="ocean"] {
    --accent: #2563eb;
    --accent-strong: #1d4ed8;
    --accent-glow: rgba(37, 99, 235, 0.35);
}
:root[data-accent="forest"] {
    --accent: #059669;
    --accent-strong: #047857;
    --accent-glow: rgba(5, 150, 105, 0.35);
}
:root[data-accent="plum"] {
    --accent: #8b5cf6;
    --accent-strong: #7c3aed;
    --accent-glow: rgba(139, 92, 246, 0.35);
}

/* ---- Global Canvas Background ---- */
.app {
    background: radial-gradient(circle at 50% -10%, color-mix(in srgb, var(--accent) 8%, var(--desk-2)) 0%, var(--desk-2) 35%, var(--desk) 90%) !important;
    position: relative;
    overflow: hidden;
}

/* Ambient glow orb for depth */
.app::before {
    content: "";
    position: absolute;
    width: 700px;
    height: 700px;
    top: -200px;
    left: 50%;
    transform: translateX(-50%);
    background: radial-gradient(circle, color-mix(in srgb, var(--accent) 12%, transparent) 0%, transparent 70%);
    pointer-events: none;
    z-index: 1;
}

/* ---- Appbar (Header) Elevated ---- */
.appbar {
    height: 64px !important;
    padding: 0 22px !important;
    background: var(--chrome) !important;
    backdrop-filter: var(--glass-blur) !important;
    -webkit-backdrop-filter: var(--glass-blur) !important;
    border-bottom: 1px solid var(--chrome-border) !important;
    box-shadow: 0 4px 20px -4px rgba(0, 0, 0, 0.04) !important;
    z-index: 50 !important;
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
    cursor: default;
    user-select: none;
}

.brand-mark {
    width: 36px !important;
    height: 36px !important;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent);
    filter: drop-shadow(0 4px 10px var(--accent-glow));
    transition: transform 0.25s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.brand:hover .brand-mark {
    transform: rotate(-3deg) scale(1.06);
}

.brand-name {
    font-family: var(--sans) !important;
    font-size: 19px !important;
    font-weight: 700 !important;
    letter-spacing: -0.025em !important;
    color: var(--chrome-ink) !important;
    display: flex;
    align-items: center;
    gap: 8px;
}

/* Pro Badge next to brand */
.brand-badge {
    display: inline-flex;
    align-items: center;
    padding: 2px 7px;
    font-size: 10px;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--accent);
    background: var(--accent-soft);
    border: 1px solid color-mix(in srgb, var(--accent) 30%, transparent);
    border-radius: var(--radius-full);
}

/* Appbar Action Buttons */
.btn {
    border-radius: var(--radius-md) !important;
    font-family: var(--sans) !important;
    font-weight: 600 !important;
    transition: all 0.18s cubic-bezier(0.2, 0.8, 0.2, 1) !important;
    border: 1px solid var(--chrome-border) !important;
    background: var(--chrome) !important;
    backdrop-filter: blur(8px) !important;
}

.btn:hover:not(:disabled) {
    transform: translateY(-1.5px);
    border-color: color-mix(in srgb, var(--accent) 45%, var(--chrome-border)) !important;
    box-shadow: 0 6px 18px -4px rgba(0, 0, 0, 0.08) !important;
}

.btn:active:not(:disabled) {
    transform: translateY(0.5px) !important;
}

.btn-icon {
    width: 38px !important;
    height: 38px !important;
}

/* Active pressed states */
.btn[aria-pressed="true"], .btn.is-active {
    background: var(--accent-soft) !important;
    color: var(--accent-strong) !important;
    border-color: color-mix(in srgb, var(--accent) 40%, transparent) !important;
}

/* ---- Empty State (The Showpiece Hero) ---- */
.state {
    z-index: 10 !important;
}

.hero {
    max-width: 680px !important;
    padding: 20px 16px 40px;
}

/* 3D Floating Book Visual */
.hero-mark {
    width: 108px !important;
    height: 108px !important;
    margin-bottom: 6px;
    color: var(--accent) !important;
    filter: drop-shadow(0 20px 32px var(--accent-glow)) drop-shadow(0 6px 12px rgba(0, 0, 0, 0.08)) !important;
    animation: floaty 5s ease-in-out infinite !important;
}

@keyframes floaty {
    0%, 100% {
        transform: translateY(0) rotate(0deg);
    }
    50% {
        transform: translateY(-9px) rotate(0.6deg);
    }
}

/* Eyebrow Badge Pill */
.hero-eyebrow-container {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 16px;
    background: var(--accent-soft);
    border: 1px solid color-mix(in srgb, var(--accent) 26%, transparent);
    border-radius: var(--radius-full);
    margin-top: 18px;
    box-shadow: 0 2px 10px -2px color-mix(in srgb, var(--accent) 20%, transparent);
}

.hero-pulse-dot {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--accent);
    box-shadow: 0 0 0 0 var(--accent);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% {
        box-shadow: 0 0 0 0 color-mix(in srgb, var(--accent) 60%, transparent);
    }
    70% {
        box-shadow: 0 0 0 8px transparent;
    }
    100% {
        box-shadow: 0 0 0 0 transparent;
    }
}

.hero-eyebrow {
    margin-top: 0 !important;
    font-family: var(--sans) !important;
    font-size: 11.5px !important;
    font-weight: 750 !important;
    letter-spacing: 0.14em !important;
    text-transform: uppercase !important;
    color: var(--accent-strong) !important;
}

/* Main Hero Title */
.hero-title {
    margin: 16px 0 0 !important;
    font-family: var(--serif) !important;
    font-size: 46px !important;
    line-height: 1.12 !important;
    font-weight: 600 !important;
    letter-spacing: -0.025em !important;
    color: var(--on-desk) !important;
    text-wrap: balance;
}

.hero-body {
    margin: 14px auto 0 !important;
    font-size: 16px !important;
    line-height: 1.65 !important;
    color: var(--muted-desk) !important;
    max-width: 520px !important;
}

/* Feature Highlights Grid */
.hero-features {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px 14px;
    margin: 22px auto 0;
    max-width: 620px;
}

.feat-pill {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    padding: 6px 13px;
    background: var(--chrome);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--chrome-border);
    border-radius: var(--radius-full);
    font-size: 12.5px;
    font-weight: 600;
    color: var(--chrome-ink);
    box-shadow: 0 2px 8px -1px rgba(0, 0, 0, 0.04);
    transition: transform 0.15s ease, border-color 0.15s ease;
}

.feat-pill:hover {
    transform: translateY(-1.5px);
    border-color: color-mix(in srgb, var(--accent) 40%, var(--chrome-border));
}

.feat-icon {
    font-size: 13px;
}

/* Modern Drop Card Container */
.drop-card {
    margin-top: 26px !important;
    width: 100% !important;
    max-width: 540px !important;
    border: 2px dashed color-mix(in srgb, var(--accent) 35%, var(--line)) !important;
    border-radius: 22px !important;
    padding: 32px 28px !important;
    background: var(--chrome) !important;
    backdrop-filter: var(--glass-blur) !important;
    -webkit-backdrop-filter: var(--glass-blur) !important;
    box-shadow: var(--shadow-card) !important;
    transition: all 0.25s cubic-bezier(0.2, 0.8, 0.2, 1) !important;
    position: relative;
    overflow: hidden;
}

.drop-card::before {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 50% 0%, var(--accent-soft) 0%, transparent 75%);
    opacity: 0.5;
    pointer-events: none;
}

.drop-card:hover, .app.is-dragover .drop-card {
    border-color: var(--accent) !important;
    box-shadow: 0 24px 56px -12px var(--accent-glow), 0 0 0 1px var(--accent) inset !important;
    transform: translateY(-3px);
}

.drop-card-title {
    font-size: 16px !important;
    font-weight: 700 !important;
    color: var(--on-desk) !important;
    letter-spacing: -0.01em;
}

.drop-card-sub {
    margin: 6px 0 24px !important;
    font-size: 13.5px !important;
    color: var(--muted-desk) !important;
}

.drop-card-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    justify-content: center;
    position: relative;
    z-index: 2;
}

/* Hero CTA Buttons */
.btn-primary {
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-strong) 100%) !important;
    border: none !important;
    color: #ffffff !important;
    box-shadow: 0 8px 24px -4px var(--accent-glow) !important;
    position: relative;
    overflow: hidden;
}

.btn-primary:hover:not(:disabled) {
    background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 90%, #fff) 0%, var(--accent-strong) 100%) !important;
    box-shadow: 0 12px 28px -2px var(--accent-glow) !important;
    transform: translateY(-2px);
    color: #ffffff !important;
}

.btn-lg {
    height: 50px !important;
    padding: 0 24px !important;
    border-radius: 14px !important;
    font-size: 15px !important;
    font-weight: 650 !important;
    gap: 10px !important;
}

.btn-lg .icon {
    width: 20px !important;
    height: 20px !important;
}

/* Secondary Button In Drop Card */
.drop-card-actions .btn:not(.btn-primary) {
    background: var(--chrome-solid) !important;
    border: 1.5px solid var(--chrome-border) !important;
    box-shadow: 0 4px 14px -2px rgba(0, 0, 0, 0.05) !important;
}

.drop-card-actions .btn:not(.btn-primary):hover {
    border-color: var(--accent) !important;
    color: var(--accent-strong) !important;
}

/* Sample Book CTA */
.link-btn {
    margin-top: 24px !important;
    padding: 10px 20px !important;
    border-radius: var(--radius-full) !important;
    background: var(--chrome) !important;
    border: 1px solid var(--chrome-border) !important;
    box-shadow: 0 4px 14px -2px rgba(0, 0, 0, 0.05) !important;
    color: var(--accent-strong) !important;
    font-size: 14px !important;
    font-weight: 650 !important;
    transition: all 0.2s cubic-bezier(0.2, 0.8, 0.2, 1) !important;
    gap: 8px !important;
}

.link-btn:hover {
    background: var(--accent-soft) !important;
    border-color: color-mix(in srgb, var(--accent) 35%, transparent) !important;
    transform: translateY(-1.5px);
    gap: 12px !important;
}

/* Keyboard Shortcut Badges */
.hero-hints {
    margin-top: 26px !important;
    display: flex !important;
    flex-wrap: wrap !important;
    gap: 12px 18px !important;
    align-items: center !important;
    justify-content: center !important;
    font-size: 12.5px !important;
    color: var(--muted-desk) !important;
}

.hero-hint-item {
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.key-cap {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 24px;
    height: 22px;
    padding: 0 6px;
    font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
    font-size: 11px;
    font-weight: 700;
    color: var(--chrome-ink);
    background: var(--chrome-solid);
    border: 1px solid var(--chrome-border);
    border-bottom: 2px solid color-mix(in srgb, var(--chrome-ink) 25%, var(--chrome-border));
    border-radius: 6px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
}

/* ---- Reader Controls (The Dock Pill) ---- */
.control-pill {
    bottom: 24px !important;
    background: var(--chrome) !important;
    backdrop-filter: var(--glass-blur) !important;
    -webkit-backdrop-filter: var(--glass-blur) !important;
    border: 1px solid var(--chrome-border) !important;
    border-radius: var(--radius-full) !important;
    box-shadow: var(--shadow-pill) !important;
    padding: 8px 14px !important;
    gap: 6px !important;
}

.pill-btn {
    width: 38px !important;
    height: 38px !important;
    border-radius: var(--radius-md) !important;
    transition: all 0.16s cubic-bezier(0.2, 0.8, 0.2, 1) !important;
}

.pill-btn:hover:not(:disabled) {
    background: var(--accent-soft) !important;
    color: var(--accent-strong) !important;
    transform: translateY(-1px);
}

.pill-page input {
    height: 32px !important;
    border-radius: var(--radius-sm) !important;
    font-weight: 600 !important;
    border: 1px solid var(--chrome-border) !important;
    background: var(--paper) !important;
}

.pill-page input:focus-visible {
    outline: 2px solid var(--accent) !important;
    border-color: transparent !important;
}

/* Navigation Side Arrows */
.nav-arrow {
    width: 52px !important;
    height: 52px !important;
    background: var(--chrome) !important;
    backdrop-filter: var(--glass-blur) !important;
    -webkit-backdrop-filter: var(--glass-blur) !important;
    border: 1px solid var(--chrome-border) !important;
    box-shadow: 0 10px 28px -4px rgba(40, 30, 20, 0.16) !important;
    transition: all 0.2s cubic-bezier(0.2, 0.8, 0.2, 1) !important;
}

.nav-arrow:hover:not(:disabled) {
    background: var(--accent) !important;
    color: #ffffff !important;
    transform: translateY(-50%) scale(1.1) !important;
    box-shadow: 0 12px 32px -4px var(--accent-glow) !important;
}

/* ---- Dialogs and Dropzone ---- */
.dlg {
    border-radius: 20px !important;
    border: 1px solid var(--chrome-border) !important;
    background: var(--chrome-solid) !important;
    box-shadow: var(--shadow-pop) !important;
}

.dlg::backdrop {
    background: rgba(18, 14, 10, 0.55) !important;
    backdrop-filter: blur(8px) !important;
    -webkit-backdrop-filter: blur(8px) !important;
}

.dropzone-inner {
    border-radius: 26px !important;
    border: 3px dashed var(--accent) !important;
    background: var(--chrome-solid) !important;
    box-shadow: 0 30px 70px -10px var(--accent-glow) !important;
}

/* Responsive refinements */
@media (max-width: 640px) {
    .hero-title {
        font-size: 34px !important;
    }
    .hero-features {
        display: none;
    }
    .drop-card {
        padding: 24px 18px !important;
    }
    .btn-lg {
        width: 100%;
    }
}

/* ---- Share Dialog ---- */
.share-box {
    margin: 16px 0;
}

.share-label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    color: var(--ink-muted);
    margin-bottom: 6px;
}

.share-input-row {
    display: flex;
    gap: 8px;
    align-items: center;
}

.share-input-row input {
    flex: 1;
    height: 42px;
    padding: 0 14px;
    border-radius: 10px;
    border: 1px solid var(--chrome-border);
    background: var(--chip-bg);
    color: var(--ink);
    font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
    font-size: 13px;
    outline: none;
    transition: border-color 0.15s ease;
}

.share-input-row input:focus {
    border-color: var(--accent);
}

.share-input-row .btn {
    height: 42px;
    padding: 0 16px;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    white-space: nowrap;
}

/* ---- Layout Stability & Corner Flip Anti-Jitter ---- */
.viewport {
    overflow: hidden !important;
}

.viewport.is-zoomed {
    overflow: auto !important;
}

/* Isolate book container so rotated 3D fold shadows never leak scrollable bounds */
.book-container {
    overflow: hidden;
    position: relative;
    z-index: 1;
}

/* StPageFlip shadow elements must not intercept cursor events or cause layout thrashing */
.stf__outerShadow,
.stf__innerShadow,
.stf__hardShadow,
.stf__hardInnerShadow {
    pointer-events: none !important;
}

/* Never show the unstyled reopen button while reading */
#btn-reopen,
.app.reading #btn-reopen,
.app.state-reading #btn-reopen {
    display: none !important;
}

/* ---- Theme & Accent Swatches Styling ---- */
.swatches {
    display: flex;
    gap: 8px;
    align-items: center;
}

.swatch {
    width: 24px !important;
    height: 24px !important;
    border-radius: 50% !important;
    cursor: pointer;
    transition: transform 0.18s cubic-bezier(0.2, 0.8, 0.2, 1), box-shadow 0.18s ease !important;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.12) !important;
}

.swatch:hover {
    transform: scale(1.22) !important;
}

.swatch[aria-pressed="true"] {
    outline: 2.5px solid var(--accent) !important;
    outline-offset: 2.5px !important;
    transform: scale(1.1) !important;
}