:root {
    --color-primary: #3a4efb;
    --color-secondary: #33a4fa;
    --color-accent: #e3ff3b;
    --color-dark: #252943;
    --color-light: #dee0ed;
    --color-white: #ffffff;
    --color-text: #252943;
    --color-surface: #dfe2ef;
    --color-surface-strong: #cfd5ea;
    --color-danger: #ff4c4c;
    --color-overlay: rgba(0, 0, 0, 0.52);
    --color-shadow: rgba(37, 41, 67, 0.18);
    --color-card-border: rgba(255, 255, 255, 0.4);
    --color-card-glow: rgba(227, 255, 59, 0.18);
    --color-soft-shadow: 0 22px 48px rgba(37, 41, 67, 0.2);
    --gradient-main: linear-gradient(135deg, #3a4efb 0%, #33a4fa 100%);
    --gradient-dark: linear-gradient(135deg, #252943 0%, #303659 100%);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Trebuchet MS', sans-serif;
    -webkit-tap-highlight-color: transparent;
    -webkit-touch-callout: none;
}

body {
    min-height: 100dvh;
    background:
        radial-gradient(circle at 12% 14%, rgba(58, 78, 251, 0.16), transparent 42%),
        radial-gradient(circle at 88% 8%, rgba(227, 255, 59, 0.2), transparent 36%),
        linear-gradient(180deg, #eef1fb 0%, #e5e9f8 48%, #dee4f4 100%);
    display: block;
    color: var(--color-text);
    padding: 0;
    position: relative;
    overflow-x: hidden;
    transition: padding-top 0.28s ease;
}

body::before,
body::after {
    display: none;
}

/* CARD GENERICHE */
.card {
    width: 100%;
    max-width: none;
    min-height: 100dvh;
    padding: calc(env(safe-area-inset-top, 0px) + 26px) 20px calc(env(safe-area-inset-bottom, 0px) + 24px);
    text-align: center;
    position: relative;
    color: var(--color-text);
    background: transparent;
    box-shadow: none;
    border: none;
    border-radius: 0;
    overflow: visible;
    z-index: 1;
}

.card::before {
    display: none;
}

/* INPUTS */
input {
    width: 100%;
    padding: 15px 16px;
    margin: 16px 0 14px;
    border-radius: 16px;
    border: 1px solid rgba(37, 41, 67, 0.12);
    outline: none;
    font-size: 15px;
    background: rgba(223, 226, 239, 0.65);
    color: var(--color-text);
    transition: border-color .2s ease, box-shadow .2s ease, background .2s ease;
}

input:focus {
    border-color: rgba(58, 78, 251, 0.35);
    box-shadow: 0 0 0 4px rgba(58, 78, 251, 0.12);
    background: var(--color-white);
}

/* BUTTONS */
button {
    padding: 15px 18px;
    width: 100%;
    border: none;
    border-radius: 16px;
    font-weight: bold;
    cursor: pointer;
    background: var(--gradient-dark);
    color: var(--color-white);
    letter-spacing: 0.02em;
    box-shadow: 0 14px 28px rgba(37, 41, 67, 0.18);
    transition: transform .18s ease, box-shadow .18s ease, opacity .18s ease;
    touch-action: manipulation;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 18px 30px rgba(37, 41, 67, 0.22);
}

button:active {
    transform: translateY(0) scale(0.99);
}

/* HOME (POST LOGIN) */
#home:not(.hidden) {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
}

#home {
    padding-top: calc(env(safe-area-inset-top, 0px) + 22px);
}

#home::before {
    display: none;
}

.section-brand {
    width: 100%;
    max-width: 760px;
    margin-bottom: 18px;
    text-align: center;
    font-size: 1.25rem;
    font-weight: 900;
    letter-spacing: 0.04em;
    color: var(--color-dark);
}

#home img {
    width: 100%;
    max-width: 420px;
    margin-bottom: 22px;
    border-radius: 20px;
    box-shadow: 0 14px 28px rgba(37, 41, 67, 0.12);
}

#home button {
    width: 220px;
}

#login:not(.hidden) {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    gap: 2px;
}

#login > :not(.watermark-link),
#home > :not(.watermark-link) {
    width: min(100%, 460px);
    margin-left: auto;
    margin-right: auto;
}

#chapters > :not(.watermark-link) {
    width: min(100%, 820px);
    margin-left: auto;
    margin-right: auto;
}

#home > button {
    width: 220px;
    max-width: 220px;
}

/* CHAPTERS */
.lesson-card {
    width: 100%;
    max-width: none;
    min-height: 100dvh;
    height: auto;
    padding-top: calc(env(safe-area-inset-top, 0px) + 22px);
    padding-bottom: calc(env(safe-area-inset-bottom, 0px) + 26px);
    display: flex;
    flex-direction: column;
}

.lesson-head {
    text-align: center;
    padding-bottom: 18px;
    border-bottom: 1px solid rgba(37, 41, 67, 0.12);
}

.lesson-kicker {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 8px 14px;
    border-radius: 999px;
    margin-bottom: 12px;
    background: rgba(227, 255, 59, 0.9);
    color: var(--color-dark);
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.lesson-head h2 {
    margin-bottom: 10px;
}

.lesson-head p {
    color: rgba(37, 41, 67, 0.7);
    line-height: 1.55;
    max-width: 470px;
    margin: 0 auto;
}

.lesson-summary {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 12px;
    margin-top: 20px;
}

.lesson-pill {
    min-height: 86px;
    padding: 14px 16px;
    border-radius: 22px;
    background: rgba(255, 255, 255, 0.82);
    display: grid;
    align-content: space-between;
    box-shadow: 0 10px 20px rgba(37, 41, 67, 0.05);
}

.lesson-pill-label {
    font-size: 0.72rem;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: rgba(37, 41, 67, 0.55);
}

.lesson-pill strong {
    font-size: 1.08rem;
    color: var(--color-dark);
}

.lesson-board {
    margin-top: 18px;
    padding: 14px 0 0;
    border-radius: 0;
    background: transparent;
    border: none;
    box-shadow: none;
    flex: 1;
    min-height: 0;
    display: grid;
    grid-template-rows: auto 1fr auto;
    gap: 10px;
    overflow: hidden;
}

/* =====================
   CARD STACK SELECTOR
   ===================== */
.card-selector {
    display: grid;
    align-content: start;
    justify-items: center;
    gap: 12px;
    padding: 6px 0 4px;
    min-height: 0;
}

.card-selector-hint {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 7px 14px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.92);
    color: var(--color-dark);
    box-shadow: 0 8px 20px rgba(37, 41, 67, 0.1);
    animation: cardHintFloat 1.9s ease-in-out infinite;
    pointer-events: none;
}

.card-selector-hint-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--color-accent);
    box-shadow: 0 0 0 7px rgba(227, 255, 59, 0.18);
    flex-shrink: 0;
}

.card-selector-hint-text {
    font-size: 0.78rem;
    font-weight: 800;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    white-space: nowrap;
}

@keyframes cardHintFloat {
    0%, 100% { transform: translateY(0); box-shadow: 0 8px 20px rgba(37, 41, 67, 0.1); }
    50% { transform: translateY(-4px); box-shadow: 0 12px 24px rgba(37, 41, 67, 0.14); }
}

.card-selector-viewport {
    position: relative;
    width: 100%;
    height: 210px;
    overflow: hidden;
    mask-image: linear-gradient(to right, transparent 0%, #000 15%, #000 85%, transparent 100%);
    -webkit-mask-image: linear-gradient(to right, transparent 0%, #000 15%, #000 85%, transparent 100%);
}

.chapter-card-track {
    position: absolute;
    top: 0;
    left: 0;
    display: flex;
    align-items: center;
    height: 100%;
    gap: 16px;
    will-change: transform;
    transition: transform 0.38s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    touch-action: none;
    user-select: none;
    cursor: grab;
}

.chapter-card-track.is-dragging {
    transition: none;
    cursor: grabbing;
}

.chapter-card {
    flex-shrink: 0;
    width: 140px;
    height: 185px;
    border-radius: 20px;
    background: var(--gradient-dark);
    color: var(--color-white);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 10px;
    box-shadow: 0 16px 32px rgba(37, 41, 67, 0.24);
    cursor: pointer;
    transition: transform 0.38s cubic-bezier(0.25, 0.46, 0.45, 0.94),
                opacity 0.38s ease,
                box-shadow 0.38s ease;
    transform-origin: center center;
    border: 1.5px solid rgba(255, 255, 255, 0.1);
    will-change: transform, opacity;
    position: relative;
    overflow: hidden;
}

.chapter-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 20%;
    right: 20%;
    height: 1px;
    background: rgba(255, 255, 255, 0.22);
}

.chapter-card.is-active {
    background: var(--gradient-main);
    box-shadow: 0 22px 44px rgba(58, 78, 251, 0.34);
    border-color: rgba(255, 255, 255, 0.24);
}

.chapter-card-label {
    font-size: 0.7rem;
    font-weight: 800;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    opacity: 0.7;
}

.chapter-card-number {
    font-size: 3rem;
    font-weight: 900;
    line-height: 1;
    letter-spacing: -0.02em;
}

.chapter-card-dots {
    display: flex;
    align-items: center;
    gap: 4px;
    flex-wrap: nowrap;
    justify-content: center;
}

.chapter-card-dot {
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: rgba(37, 41, 67, 0.18);
    transition: width 0.24s ease, background 0.24s ease, border-radius 0.24s ease;
    flex-shrink: 0;
    cursor: pointer;
}

.chapter-card-dot.is-active {
    width: 16px;
    border-radius: 3px;
    background: var(--color-primary);
}

/* =====================
   DASHBOARD
   ===================== */
.dashboard {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
    padding: 2px 0;
    align-self: center;
}

.dash-gauge {
    width: 70px;
    height: 70px;
    border-radius: 50%;
    padding: 0;
    background: transparent;
    border: none;
    box-shadow: none;
    cursor: pointer;
    touch-action: manipulation;
    flex-shrink: 0;
    transition: transform 0.12s ease;
}

.dash-gauge img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    border-radius: 50%;
    pointer-events: none;
    display: block;
}

.dash-gauge.gauge-pulse {
    animation: gaugePulse 0.38s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes gaugePulse {
    0%   { transform: scale(1); }
    35%  { transform: scale(0.84); }
    70%  { transform: scale(1.12); }
    100% { transform: scale(1); }
}

/* Engine button */
.dash-engine {
    width: 90px;
    height: 90px;
    border-radius: 50%;
    padding: 0;
    background: transparent;
    border: none;
    box-shadow: none;
    cursor: pointer;
    touch-action: manipulation;
    position: relative;
    flex-shrink: 0;
    animation: engineIdle 3s ease-in-out infinite;
}

.dash-engine::before {
    content: '';
    position: absolute;
    inset: -10px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(58, 78, 251, 0.16) 0%, transparent 65%);
    animation: engineRing 3s ease-in-out infinite;
    pointer-events: none;
}

.dash-engine img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    border-radius: 50%;
    pointer-events: none;
    display: block;
    position: relative;
    z-index: 1;
    transition: opacity 0.22s ease;
}

@keyframes engineIdle {
    0% {
        transform: scale(1) rotate(0deg);
        filter: drop-shadow(0 0 3px rgba(58, 78, 251, 0.18))
                drop-shadow(0 2px 6px rgba(37, 41, 67, 0.1));
    }
    20% {
        transform: scale(1.028) rotate(0.45deg);
        filter: drop-shadow(0 0 9px rgba(58, 78, 251, 0.36))
                drop-shadow(0 3px 9px rgba(37, 41, 67, 0.13));
    }
    50% {
        transform: scale(1.042) rotate(0deg);
        filter: drop-shadow(0 0 20px rgba(58, 78, 251, 0.58))
                drop-shadow(0 5px 14px rgba(37, 41, 67, 0.17));
    }
    80% {
        transform: scale(1.028) rotate(-0.45deg);
        filter: drop-shadow(0 0 9px rgba(58, 78, 251, 0.36))
                drop-shadow(0 3px 9px rgba(37, 41, 67, 0.13));
    }
    100% {
        transform: scale(1) rotate(0deg);
        filter: drop-shadow(0 0 3px rgba(58, 78, 251, 0.18))
                drop-shadow(0 2px 6px rgba(37, 41, 67, 0.1));
    }
}

@keyframes engineRing {
    0%, 100% { opacity: 0.28; transform: scale(1); }
    50%       { opacity: 0.82; transform: scale(1.12); }
}

.dash-engine.is-starting {
    animation: engineBoot 0.55s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
}

.dash-engine.is-starting::before {
    animation: none;
    opacity: 0;
}

@keyframes engineBoot {
    0%   { transform: scale(1);    filter: drop-shadow(0 0 4px rgba(58, 78, 251, 0.22)); }
    18%  { transform: scale(0.87); filter: drop-shadow(0 0 3px rgba(58, 78, 251, 0.1)); }
    58%  { transform: scale(1.12); filter: drop-shadow(0 0 24px rgba(227, 255, 59, 0.95)); }
    78%  { transform: scale(0.97); filter: drop-shadow(0 0 18px rgba(227, 255, 59, 0.7)); }
    100% { transform: scale(1);    filter: drop-shadow(0 0 12px rgba(227, 255, 59, 0.45)); }
}

/* Screen shake */
@keyframes engineShake {
    0%   { transform: translate(0, 0) rotate(0deg); }
    10%  { transform: translate(-3px, -1px) rotate(-0.25deg); }
    22%  { transform: translate(3px, 1px) rotate(0.25deg); }
    33%  { transform: translate(-2px, 2px) rotate(-0.2deg); }
    44%  { transform: translate(2px, -1px) rotate(0.15deg); }
    55%  { transform: translate(-1.5px, 1px) rotate(-0.1deg); }
    66%  { transform: translate(1.5px, -1.5px) rotate(0.1deg); }
    77%  { transform: translate(-1px, 0.5px) rotate(0); }
    88%  { transform: translate(0.5px, -0.5px) rotate(0); }
    100% { transform: translate(0, 0) rotate(0); }
}

#chapters.engine-shaking {
    animation: engineShake 0.45s ease-out;
}

/* Flash overlay */
.engine-flash {
    position: fixed;
    inset: 0;
    background: radial-gradient(circle at 50% 60%, rgba(227, 255, 59, 0.2) 0%, transparent 65%);
    pointer-events: none;
    z-index: 2000;
    animation: flashFade 0.55s ease-out forwards;
}

@keyframes flashFade {
    0%   { opacity: 1; }
    100% { opacity: 0; }
}

.lesson-actions {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
    margin-top: 0;
}

.lesson-tool {
    min-height: 72px;
    padding: 14px 18px;
    border-radius: 22px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.lesson-tool strong {
    font-size: 1.5rem;
    font-weight: 900;
    line-height: 1;
    letter-spacing: 0.01em;
}

.lesson-tool-exam {
    background: linear-gradient(135deg, #e3ff3b 0%, #d1ff38 100%);
    color: var(--color-dark);
    box-shadow: 0 16px 28px rgba(227, 255, 59, 0.22);
}

.lesson-tool-quiz {
    background: var(--gradient-main);
    color: var(--color-white);
}

#examButton {
    margin: 0;
}

/* VIEWER */
#viewer {
    position: fixed;
    inset: 0;
    background: #000;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    padding: 20px;
}

.viewer-back-btn {
    position: fixed;
    top: 16px;
    left: 16px;
    width: auto;
    padding: 10px 14px;
    border-radius: 12px;
    background: rgba(0, 0, 0, 0.58);
    color: var(--color-white);
    box-shadow: none;
    z-index: 20;
}

.viewer-back-btn:hover {
    background: rgba(0, 0, 0, 0.7);
    transform: translateY(0);
    box-shadow: none;
}

/* PAGE CONTAINER */
.page { position: relative; max-width: 900px; margin: 20px auto; }

/* PAGE IMAGE */
.page img {
    width: 100%;
    display: block;
    user-select: none;
    -webkit-user-drag: none;
    pointer-events: none;
    position: relative;
    z-index: 1;
}

/* Shield invisibile sopra i contenuti */
.page .shield {
  position: absolute;
  inset: 0;
  background: transparent;
  z-index: 10; /* sopra l'immagine ma sotto UI */
  touch-action: none; /* disabilita long press e gestures */
  pointer-events: none;

}


/* BACK BUTTON */
.back {
    width: auto;
    margin-bottom: 15px;
    padding: 10px 18px;
}

/* HELPERS */
.hidden { display: none; }
#err { color: var(--color-danger); margin-top: 10px; font-size: 14px; }

/* WATERMARK LINK */
.watermark-link {
    position: static;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    margin-top: auto;
    padding: 10px 0 4px;
    border-radius: 0;
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.03em;
    color: rgba(37, 41, 67, 0.32);
    text-decoration: none;
    background: none;
    box-shadow: none;
    transition: color 0.2s ease;
    z-index: 6;
}

.watermark-link:hover,
.watermark-link:focus-visible {
    color: var(--color-primary);
    background: none;
    box-shadow: none;
    transform: none;
}

.watermark-tip {
    display: none;
}

/* WHATSAPP FLOATING BUTTON */
#whatsappBtn {
    position: fixed;
    bottom: 18px;
    right: 14px;
    width: 46px;
    height: 46px;
    border-radius: 50%;
    background: #25D366;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 800;
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.16);
    touch-action: none;
    border: none;
    opacity: 0.9;
    transition: transform 0.18s ease, box-shadow 0.18s ease, opacity 0.18s ease;
}

#whatsappBtn:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.22);
    opacity: 1;
}

#whatsappBtn img {
    width: 26px;
    height: 26px;
    pointer-events: none;
}

/* =====================
   APP HEADER / STATUS BAR
   ===================== */
.app-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 60px;
    background: var(--gradient-main);
    box-shadow: 0 4px 20px rgba(58, 78, 251, 0.28);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 12px;
    z-index: 1000;
    opacity: 0;
    transform: translateY(-12px);
    visibility: hidden;
    pointer-events: none;
    transition: opacity 0.28s ease, transform 0.28s ease, visibility 0s linear 0.28s;
}

.app-header.is-visible {
    opacity: 1;
    transform: translateY(0);
    visibility: visible;
    pointer-events: auto;
    transition: opacity 0.28s ease, transform 0.28s ease;
}

.header-left,
.header-center,
.header-right {
    display: flex;
    align-items: center;
    gap: 8px;
}

.header-left { flex: 0 0 48px; }
.header-center { flex: 1; justify-content: center; }
.header-right { flex: 0 0 48px; justify-content: flex-end; }

.header-btn {
    width: 44px;
    height: 44px;
    padding: 0;
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.18);
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.18s ease, transform 0.14s ease;
    box-shadow: none;
}

.header-btn:hover  { background: rgba(255, 255, 255, 0.28); }
.header-btn:active { transform: scale(0.92); background: rgba(255, 255, 255, 0.35); }

.header-btn img {
    width: 24px;
    height: 24px;
    filter: brightness(0) invert(1);
    pointer-events: none;
}

.header-btn.back-hidden {
    opacity: 0;
    pointer-events: none;
}

.chapter-status {
    display: flex;
    align-items: center;
    gap: 8px;
    color: white;
    font-size: 14px;
    font-weight: 700;
    letter-spacing: 0.02em;
    max-width: 200px;
    overflow: hidden;
}

.chapter-status span {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.status-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
    filter: brightness(0) invert(1);
    object-fit: contain;
}

/* =====================
   MENU OVERLAY (backdrop)
   ===================== */
.menu-overlay {
    position: fixed;
    inset: 0;
    background: rgba(37, 41, 67, 0.48);
    z-index: 998;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.28s ease;
    backdrop-filter: blur(3px);
    -webkit-backdrop-filter: blur(3px);
}

.menu-overlay.overlay-visible {
    opacity: 1;
    pointer-events: auto;
}

/* =====================
   CHAPTER SIDE MENU (slide-in panel)
   ===================== */
.chapter-menu {
    position: fixed;
    top: 0;
    right: 0;
    width: min(320px, 88vw);
    height: 100dvh;
    height: 100vh;
    background: var(--color-white);
    box-shadow: -12px 0 40px rgba(37, 41, 67, 0.22);
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    z-index: 999;
    transform: translateX(100%);
    transition: transform 0.32s cubic-bezier(0.4, 0, 0.2, 1);
    border-radius: 20px 0 0 20px;
    overscroll-behavior: contain;
}

.chapter-menu.menu-open {
    transform: translateX(0);
}

/* ---- Menu header ---- */
.menu-header {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 20px 18px 14px;
    background: var(--gradient-main);
    position: sticky;
    top: 0;
    z-index: 2;
}

.menu-logo {
    width: 30px;
    height: 30px;
    object-fit: contain;
    flex-shrink: 0;
    filter: brightness(0) invert(1);
}

.menu-brand {
    flex: 1;
    font-size: 15px;
    font-weight: 800;
    color: white;
    letter-spacing: 0.03em;
}

.menu-close-btn {
    width: 36px;
    height: 36px;
    min-width: 36px;
    padding: 0;
    border-radius: 10px;
    background: rgba(255, 255, 255, 0.2);
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 15px;
    font-weight: 700;
    box-shadow: none;
    transition: background 0.16s ease, transform 0.14s ease;
    line-height: 1;
    flex-shrink: 0;
}

.menu-close-btn:hover  { background: rgba(255, 255, 255, 0.32); }
.menu-close-btn:active { transform: scale(0.9); }

/* ---- Menu body ---- */
.menu-container {
    padding-bottom: 24px;
}

.menu-item {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 14px 20px;
    cursor: pointer;
    transition: background 0.18s ease;
    border: none;
    background: transparent;
    width: 100%;
    box-shadow: none;
    color: var(--color-text);
    font-size: 15px;
    font-weight: 600;
    text-align: left;
    border-radius: 0;
    touch-action: manipulation;
}

.menu-item:hover  { background: rgba(58, 78, 251, 0.07); transform: none; }
.menu-item:active { background: rgba(58, 78, 251, 0.13); transform: none; }

.menu-home {
    font-weight: 700;
    margin-top: 4px;
}

.menu-home:hover { background: rgba(227, 255, 59, 0.16); }
.menu-home:active { background: rgba(227, 255, 59, 0.24); }

.menu-icon {
    width: 22px;
    height: 22px;
    flex-shrink: 0;
    object-fit: contain;
}

.menu-divider {
    height: 1px;
    background: rgba(37, 41, 67, 0.07);
    margin: 4px 18px;
}

.menu-section { padding: 4px 0; }

.menu-section-title {
    padding: 10px 20px 6px;
    font-size: 11px;
    font-weight: 800;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: rgba(37, 41, 67, 0.45);
}

.menu-chapters-list { display: flex; flex-direction: column; }

.menu-chapter-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 20px;
    cursor: pointer;
    transition: background 0.18s ease;
    font-size: 14px;
    font-weight: 500;
    color: var(--color-text);
    touch-action: manipulation;
}

.menu-chapter-item:hover {
    background: rgba(58, 78, 251, 0.07);
}

.menu-chapter-item.active {
    background: rgba(58, 78, 251, 0.1);
    font-weight: 700;
    color: var(--color-primary);
}

.menu-chapter-item.active .menu-chapter-num {
    background: var(--color-primary);
    color: white;
}

.menu-chapter-num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 34px;
    height: 26px;
    border-radius: 8px;
    background: rgba(58, 78, 251, 0.1);
    color: var(--color-primary);
    font-size: 11px;
    font-weight: 800;
    letter-spacing: 0.04em;
    flex-shrink: 0;
    transition: background 0.18s ease, color 0.18s ease;
}

.menu-exam {
    font-weight: 600;
    color: var(--color-dark);
}

.menu-exam:hover  { background: rgba(227, 255, 59, 0.14); }
.menu-exam:active { background: rgba(227, 255, 59, 0.22); }

.menu-quiz {
    font-weight: 600;
    color: var(--color-primary);
}

.menu-quiz:hover  { background: rgba(58, 78, 251, 0.09); }
.menu-quiz:active { background: rgba(58, 78, 251, 0.14); }

/* Prevent body scroll when menu is open */
body.body-menu-open { overflow: hidden; }

/* =====================
   APP MODE LAYOUT
   ===================== */
body.app-mode {
    padding-top: 60px;
}

body.app-mode .card {
    margin-top: 0;
    margin-bottom: 0;
}

body.app-mode .lesson-card {
    height: calc(100dvh - 60px);
    min-height: 0;
    overflow: hidden;
    margin-top: 0;
    margin-bottom: 0;
}

body.app-mode #viewer {
    padding-top: 60px;
}

/* Compact chapters layout in app-mode — everything fits in one screen */
body.app-mode #chapters .section-brand {
    display: none; /* header already shows the title */
}

body.app-mode .lesson-head {
    padding-bottom: 10px;
}

body.app-mode .lesson-head h2 {
    margin-bottom: 0;
}

body.app-mode .lesson-head p {
    display: none; /* save vertical space */
}

body.app-mode .lesson-kicker {
    margin-bottom: 6px;
    padding: 5px 12px;
    font-size: 11px;
}

body.app-mode .lesson-board {
    margin-top: 8px;
    padding-top: 8px;
    gap: 8px;
    grid-template-rows: auto 1fr auto;
    overflow: hidden;
}

body.app-mode .dashboard {
    gap: 16px;
}

body.app-mode .dash-engine {
    width: 80px;
    height: 80px;
}

body.app-mode .dash-gauge {
    width: 62px;
    height: 62px;
}

body.app-mode .lesson-actions {
    /* Keep side-by-side even on small screens */
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px;
}

body.app-mode .lesson-tool {
    min-height: 62px;
    padding: 10px 14px;
}

body.app-mode .lesson-tool strong {
    font-size: 1.35rem;
}

/* Constrain card-selector to its grid row */
body.app-mode .card-selector {
    min-height: 0;
    overflow: hidden;
    gap: 8px;
}

body.app-mode .card-selector-hint {
    display: none;
}

body.app-mode .card-selector-viewport {
    height: 190px;
}

/* Lift WhatsApp button above the exam/quiz cards in app-mode */
body.app-mode #whatsappBtn {
    bottom: calc(env(safe-area-inset-bottom, 0px) + 14px);
    opacity: 0.65;
}

/* Menu button visibility — hidden unless in chapter viewer or exam */
.menu-btn-hidden {
    opacity: 0;
    pointer-events: none;
}

/* =====================
   MOBILE OPTIMIZATIONS
   ===================== */
@media (max-height: 620px) {
    .app-header { height: 54px; }
    body.app-mode { padding-top: 54px; }
    body.app-mode .lesson-card { height: calc(100dvh - 54px); }
    body.app-mode #viewer { padding-top: 54px; }
}

@media (max-width: 520px) {
    .chapter-menu {
        width: 100%;
        border-radius: 0;
    }
}

@media (max-width: 480px) {
    .header-center { font-size: 12px; }
}

#login h1,
#chapters h2,
#home h2 {
    color: var(--color-dark);
}

#login h1 {
    font-size: 2rem;
    margin-bottom: 8px;
}

#login h2 {
    font-size: 0.95rem;
    color: rgba(37, 41, 67, 0.58);
    margin-bottom: 6px;
    font-weight: 600;
}

@media (max-width: 520px) {
    .card {
        padding: calc(env(safe-area-inset-top, 0px) + 18px) 14px calc(env(safe-area-inset-bottom, 0px) + 20px);
    }

    .lesson-card {
        height: auto;
        min-height: 100dvh;
        padding-bottom: calc(env(safe-area-inset-bottom, 0px) + 18px);
    }

    .lesson-board {
        padding: 14px 0 0;
        grid-template-rows: auto 1fr auto;
        gap: 10px;
        overflow: visible;
    }

    .lesson-head h2 {
        font-size: 2rem;
    }

    .lesson-head p {
        font-size: 0.94rem;
        line-height: 1.45;
    }

    .section-brand {
        margin-bottom: 14px;
        font-size: 1.12rem;
    }

    .card-selector-viewport {
        height: 196px;
    }

    .chapter-card-number {
        font-size: 2.6rem;
    }

    .lesson-actions {
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 10px;
    }

    .lesson-tool {
        min-height: 64px;
        padding: 12px 16px;
    }

    .lesson-tool strong {
        font-size: 1.35rem;
    }

    #home button {
        width: 100%;
    }
}

/* =====================
   SCREEN ENTRANCE ANIMATION
   ===================== */
@keyframes screenEnter {
    from {
        opacity: 0;
        transform: translateY(7px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.card:not(.hidden) {
    animation: screenEnter 0.2s ease;
}