/* ----- VARIABLES & DESIGN SYSTEM ----- */
:root {
    /* Colors - Light Theme */
    --bg-primary: #f5f5f7;
    --bg-secondary: #ffffff;
    --text-primary: #1d1d1f;
    --text-secondary: #86868b;
    --accent-blue: #0066cc;
    --accent-blue-hover: #0077ed;
    --accent-green: #34c759;
    --accent-red: #ff3b30;

    /* Layout */
    --border-radius-sm: 8px;
    --border-radius-md: 14px;
    --border-radius-lg: 24px;
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 32px;

    /* Shadows & Effects */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(0, 0, 0, 0.05);

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s cubic-bezier(0.25, 0.1, 0.25, 1);
}

/* Dark Theme Overrides */
[data-theme="dark"] {
    --bg-primary: #121212;
    /* Softer off-black instead of pure #000000 */
    --bg-secondary: #1c1c1e;
    /* Elevated card color (Apple dark mode surface) */
    --text-primary: #f5f5f7;
    --text-secondary: #86868b;
    --accent-blue: #0a84ff;
    --accent-blue-hover: #2997ff;
    --accent-green: #32d74b;
    --accent-red: #ff453a;

    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.6);
    --glass-bg: rgba(28, 28, 30, 0.75);
    --glass-border: rgba(255, 255, 255, 0.08);
    /* Slightly subtler border */
}

/* ----- RESET & BASE ----- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color var(--transition-normal), color var(--transition-normal);
    overflow-x: hidden;
}

h1,
h2,
h3 {
    font-weight: 600;
    letter-spacing: -0.02em;
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    outline: none;
    -webkit-tap-highlight-color: transparent;
}

/* ----- LAYOUT ----- */
.app-container {
    width: 100%;
    max-width: 480px;
    height: 100vh;
    height: 100dvh;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    position: relative;
    background-color: var(--bg-primary);
    transition: background-color var(--transition-normal);
}

@media (min-width: 481px) {
    .app-container {
        height: auto;
        min-height: 700px;
        border-radius: 40px;
        box-shadow: var(--shadow-lg);
        overflow: hidden;
        border: 8px solid var(--bg-secondary);
        position: relative;
    }
}

/* Header */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) var(--spacing-md);
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    z-index: 10;
    flex-wrap: wrap;
    gap: 10px;
}

.logo {
    font-size: 20px;
    font-weight: 700;
    color: var(--text-primary);
}

.logo span {
    font-weight: 400;
    color: var(--text-secondary);
}

.icon-button {
    background: transparent;
    color: var(--text-primary);
    font-size: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    transition: background-color var(--transition-fast);
}

.icon-button:hover {
    background-color: var(--glass-border);
}

/* Main Content Area */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: var(--spacing-md);
    padding-top: 80px;
    /* Space for header */
    position: relative;
}

/* SCREENS LOGIC */
.screen {
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 100%;
    animation: fadeIn 0.4s cubic-bezier(0.25, 0.1, 0.25, 1);
}

.screen.active {
    display: flex;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ----- SPECIFIC SCREENS ----- */

/* Start Screen */
.hero {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.icon-wrapper {
    width: 80px;
    height: 80px;
    background-color: var(--bg-secondary);
    border-radius: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-md);
    font-size: 40px;
    color: var(--accent-blue);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--glass-border);
}

.hero h2 {
    font-size: 28px;
    margin-bottom: var(--spacing-xs);
}

.hero p {
    color: var(--text-secondary);
    font-size: 15px;
    line-height: 1.4;
    max-width: 280px;
    margin: 0 auto;
}

/* Primary Button */
.primary-btn {
    background-color: var(--accent-blue);
    color: #ffffff;
    font-size: 17px;
    font-weight: 600;
    padding: 16px 32px;
    border-radius: var(--border-radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    width: 100%;
    max-width: 300px;
    transition: all var(--transition-fast);
    box-shadow: 0 4px 12px rgba(0, 102, 204, 0.3);
}

.primary-btn:hover {
    background-color: var(--accent-blue-hover);
    transform: scale(0.98);
}

.primary-btn:active {
    transform: scale(0.95);
}

.secondary-btn {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 17px;
    font-weight: 600;
    padding: 16px 32px;
    border-radius: var(--border-radius-lg);
    width: 100%;
    max-width: 300px;
    transition: all var(--transition-fast);
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-sm);
}

/* Statistics Box */
.stats-overview {
    width: 100%;
    max-width: 300px;
    margin-bottom: var(--spacing-lg);
    background-color: var(--bg-secondary);
    border-radius: var(--border-radius-md);
    padding: var(--spacing-sm);
    text-align: center;
    border: 1px solid var(--glass-border);
}

.stat-label {
    display: block;
    font-size: 13px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 600;
    margin-bottom: 4px;
}

.stat-value {
    font-size: 24px;
    font-weight: 700;
    color: var(--text-primary);
}


/* Quiz Screen */
.progress-container {
    width: 100%;
    margin-bottom: var(--spacing-lg);
}

.progress-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-xs);
    font-size: 14px;
    color: var(--text-secondary);
    font-weight: 500;
}

/* ----- AUTHENTICATION SYSTEM (LOGIN/REGISTER) ----- */
.auth-card {
    background: var(--bg-secondary);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 400px;
    text-align: center;
    border: 1px solid var(--glass-border);
    animation: fadeIn 0.5s ease-out forwards;
}

.auth-card .icon-wrapper {
    margin-bottom: var(--spacing-md);
}

.auth-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    text-align: left;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.input-group label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.input-group input {
    padding: 12px 16px;
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius-sm);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
    transition: var(--transition-fast);
}

.input-group input:focus {
    outline: none;
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 3px rgba(10, 132, 255, 0.2);
}

.auth-switch-text {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.auth-switch-text a {
    color: var(--accent-blue);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition-fast);
}

.auth-switch-text a:hover {
    color: var(--accent-blue-hover);
    text-decoration: underline;
}

/* ----- PROFILE SYSTEM ----- */
.profiles-container {
    text-align: center;
    width: 100%;
    max-width: 600px;
    animation: fadeIn 0.5s ease-out forwards;
    position: relative;
    z-index: 10;
}

.profiles-container h2 {
    font-size: 2rem;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.profiles-container p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
}

.profiles-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
    position: relative;
    z-index: 20;
}

.profile-card {
    background: var(--bg-secondary);
    border: 2px solid transparent;
    border-radius: var(--border-radius-md);
    padding: var(--spacing-lg) var(--spacing-md);
    cursor: pointer;
    transition: var(--transition-normal);
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    position: relative;
    z-index: 30;
}

[data-theme="dark"] .profile-card {
    background: #2c2c2e;
    /* Slightly lighter than secondary for cards */
}

/* Hover only if not touch device generally */
@media (hover: hover) {
    .profile-card:hover {
        transform: translateY(-4px);
        box-shadow: var(--shadow-md);
        border-color: var(--glass-border);
    }
}

.profile-card:active {
    transform: scale(0.96);
    box-shadow: var(--shadow-sm);
}

.profile-avatar {
    width: 64px;
    height: 64px;
    border-radius: 50%;
    background: var(--accent-blue);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: 700;
}

.profile-name {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
}

.profile-level {
    font-size: 0.9rem;
    color: var(--text-secondary);
    background: var(--bg-primary);
    padding: 4px 12px;
    border-radius: 12px;
}

.profile-add-card {
    border: 2px dashed var(--text-secondary);
    background: transparent;
    box-shadow: none;
    justify-content: center;
}

.profile-add-card:hover {
    border-color: var(--accent-blue);
    background: rgba(10, 132, 255, 0.05);
}

.profile-add-card .profile-avatar {
    background: transparent;
    color: var(--text-secondary);
    border: 2px solid var(--text-secondary);
}

.profile-add-card:hover .profile-avatar {
    color: var(--accent-blue);
    border-color: var(--accent-blue);
}

/* User Controls in Header */
.user-controls {
    display: flex;
    align-items: center;
    gap: 12px;
    width: 100%;
    order: 3;
    justify-content: center;
    margin-top: 10px;
}

.active-profile-name {
    font-weight: 600;
    color: var(--accent-blue);
    font-size: 0.9rem;
    background: rgba(10, 132, 255, 0.1);
    padding: 4px 10px;
    border-radius: 12px;
}

.text-button {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 0.9rem;
    cursor: pointer;
    font-family: inherit;
    transition: var(--transition-fast);
}

.text-button:hover {
    color: var(--text-primary);
    text-decoration: underline;
}

.header-btn {
    padding: 6px 12px;
    font-size: 0.85rem;
    display: flex;
    align-items: center;
    gap: 6px;
    width: auto;
    max-width: none;
    background: var(--bg-primary);
    /* Overrides secondary btn background to fit the header better */
}

.header-btn:hover {
    background: var(--glass-border);
}

@media (max-width: 600px) {
    .profiles-grid {
        grid-template-columns: 1fr;
    }
}

/* ----- CUSTOM UI MODAL (APPLE STYLE) ----- */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.4);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    z-index: 9999;
    display: flex;
    align-items: center;
    justify-content: center;
    animation: fadeIn 0.2s ease-out;
}

[data-theme="dark"] .modal-overlay {
    background: rgba(0, 0, 0, 0.6);
}

.modal-card {
    background: var(--bg-secondary);
    padding: 32px;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
    width: 90%;
    max-width: 360px;
    text-align: center;
    border: 1px solid var(--glass-border);
    transform: scale(0.95);
    animation: scaleUp 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
}

@keyframes scaleUp {
    from {
        opacity: 0;
        transform: scale(0.9);
    }

    to {
        opacity: 1;
        transform: scale(1);
    }
}

.modal-card h3 {
    margin-bottom: 8px;
    color: var(--text-primary);
    font-size: 1.5rem;
    font-weight: 600;
}

.modal-card p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: 24px;
}

.modal-card input {
    width: 100%;
    padding: 14px 16px;
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius-sm);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
    transition: var(--transition-fast);
    margin-bottom: 24px;
    text-align: center;
    /* Center input for aesthetics */
}

.modal-card input:focus {
    outline: none;
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 4px rgba(10, 132, 255, 0.15);
}

.modal-actions {
    display: flex;
    gap: 12px;
    justify-content: center;
}

.modal-actions button {
    flex: 1;
    padding: 12px 0;
    font-size: 1rem;
}

.modal-actions .secondary-btn {
    background: rgba(134, 134, 139, 0.1);
    color: var(--text-primary);
    border: none;
}

.modal-actions .secondary-btn:hover {
    background: rgba(134, 134, 139, 0.2);
}

.badge {
    background-color: var(--accent-blue);
    color: white;
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 600;
}

.progress-bar-bg {
    width: 100%;
    height: 6px;
    background-color: var(--bg-secondary);
    border-radius: 3px;
    overflow: hidden;
}

.progress-bar-fill {
    height: 100%;
    background-color: var(--accent-blue);
    width: 0%;
    border-radius: 3px;
    transition: width 0.4s ease-out;
}

.question-card {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius-lg);
    padding: 40px 20px;
    width: 100%;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-md);
}

.word-display {
    font-size: 36px;
    font-weight: 700;
    color: var(--text-primary);
    word-break: break-word;
}

/* Options Grid */
.options-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
    width: 100%;
}

.option-btn {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 16px;
    font-weight: 500;
    padding: 20px 16px;
    border-radius: var(--border-radius-md);
    border: 2px solid transparent;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    line-height: 1.3;
}

/* Hover only if not touch device generally */
@media (hover: hover) {
    .option-btn:hover:not(:disabled) {
        transform: translateY(-2px);
        box-shadow: var(--shadow-md);
        border-color: var(--glass-border);
    }
}

.option-btn:active:not(:disabled) {
    transform: scale(0.96);
}

/* Feedback States */
.option-btn.correct {
    background-color: var(--accent-green);
    color: white;
    border-color: var(--accent-green);
    box-shadow: 0 4px 12px rgba(52, 199, 89, 0.4);
}

.option-btn.wrong {
    background-color: var(--accent-red);
    color: white;
    border-color: var(--accent-red);
    box-shadow: 0 4px 12px rgba(255, 59, 48, 0.4);
    animation: shake 0.4s cubic-bezier(.36, .07, .19, .97) both;
}

.option-btn:disabled {
    cursor: default;
    opacity: 0.8;
}

@keyframes shake {

    10%,
    90% {
        transform: translate3d(-1px, 0, 0);
    }

    20%,
    80% {
        transform: translate3d(2px, 0, 0);
    }

    30%,
    50%,
    70% {
        transform: translate3d(-4px, 0, 0);
    }

    40%,
    60% {
        transform: translate3d(4px, 0, 0);
    }
}


/* Result Screens */
.result-card {
    text-align: center;
    width: 100%;
}

.result-card h2 {
    font-size: 28px;
    margin-bottom: var(--spacing-sm);
}

.result-card p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
}

.success-icon {
    color: var(--accent-green);
}

.trophy-icon {
    color: #ffcc00;
    /* Gold */
}

.score-display {
    background-color: var(--bg-secondary);
    border-radius: var(--border-radius-md);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    border: 1px solid var(--glass-border);
}

.score-label {
    display: block;
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.score-value {
    font-size: 32px;
    font-weight: 700;
    color: var(--accent-blue);
}

.next-level-info {
    font-size: 14px;
    background-color: var(--bg-secondary);
    padding: 12px;
    border-radius: 8px;
    border-left: 4px solid var(--accent-blue);
    margin-bottom: var(--spacing-lg);
    text-align: left;
}

/* Utilities */
.pulse-anim {
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% {
        box-shadow: 0 0 0 0 rgba(0, 102, 204, 0.4);
    }

    70% {
        box-shadow: 0 0 0 10px rgba(0, 102, 204, 0);
    }

    100% {
        box-shadow: 0 0 0 0 rgba(0, 102, 204, 0);
    }
}