/* ============================================
   BASE LAYOUT
   ============================================ */

:root {
    --container-max: 720px;
}

*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-body);
    background: var(--color-black);
    color: var(--color-gray-50);
    min-height: 100vh;
    min-height: 100dvh;
}

::selection {
    background: var(--color-blue-a30);
    color: inherit;
}

:focus-visible {
    outline: 2px solid var(--color-blue);
    outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }
}

/* Nav deltas over css/core/components.css and the presentations theme */
.nav {
    height: var(--nav-height);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
}

.nav__inner {
    justify-content: normal;
    gap: 12px;
}

.nav__back {
    gap: 8px;
    color: var(--color-blue);
    font-weight: 500;
}

.nav__title {
    color: var(--color-gray-50);
    flex: 1;
    text-align: center;
    min-width: 0;
}

.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 22px;
    position: relative;
    z-index: 1;
}

.screen {
    display: none;
    padding-top: calc(var(--nav-height) + 48px);
    padding-bottom: 80px;
    min-height: 100vh;
    min-height: 100dvh;
    position: relative;
    z-index: 1;
}

.screen.is-active {
    display: block;
    animation: screen-in 0.5s var(--ease-out-expo);
}

@keyframes screen-in {
    from { opacity: 0; transform: translateY(20px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ============================================
   PSD ACCENT — Neon green (matches presentations theme)
   Override teal tokens so all var(--color-teal*) resolve to green
   ============================================ */
:root {
    --color-teal:     #00ff88;
    --color-teal-a6:  rgba(0, 255, 136, 0.06);
    --color-teal-a10: rgba(0, 255, 136, 0.10);
    --color-teal-a12: rgba(0, 255, 136, 0.12);
    --color-teal-a15: rgba(0, 255, 136, 0.15);
    --color-teal-a20: rgba(0, 255, 136, 0.20);
    --color-teal-a25: rgba(0, 255, 136, 0.25);
    --color-teal-a30: rgba(0, 255, 136, 0.30);
}

/* ============================================
   HOME SCREEN
   ============================================ */
.psd-hero {
    text-align: center;
    margin-bottom: 48px;
}

.psd-hero__badge {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--color-teal);
    background: var(--color-teal-a10);
    padding: 6px 16px;
    border-radius: var(--border-radius-pill);
    margin-bottom: 20px;
}

.psd-hero__title {
    font-family: var(--font-display);
    font-size: clamp(28px, 5vw, 40px);
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.1;
    margin-bottom: 12px;
}

.psd-hero__subtitle {
    font-size: 17px;
    color: var(--color-gray-400);
    font-weight: 300;
    max-width: 480px;
    margin: 0 auto;
    line-height: 1.5;
}

/* --- Mode cards --- */
.psd-modes {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin-bottom: 40px;
}

.psd-mode-card {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    background: var(--color-white-a4);
    border: 1px solid var(--color-white-a8);
    border-radius: var(--border-radius-md);
    padding: 28px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.25s var(--ease-smooth);
    font-family: inherit;
    color: inherit;
}

.psd-mode-card:hover {
    background: var(--color-white-a8);
    border-color: var(--color-white-a15);
    transform: translateY(-2px);
}

.psd-mode-card__icon {
    font-size: 32px;
    margin-bottom: 12px;
    display: block;
}

.psd-mode-card__title {
    font-family: var(--font-display);
    font-size: 16px;
    font-weight: 600;
    color: var(--color-gray-100);
    margin-bottom: 6px;
}

.psd-mode-card__desc {
    font-size: 13px;
    color: var(--color-gray-500);
    line-height: 1.4;
}

/* --- Filters --- */
.psd-filters {
    margin-bottom: 32px;
}

.psd-filter-section {
    margin-bottom: 20px;
}

.psd-filter-label {
    font-family: var(--font-display);
    font-size: 13px;
    font-weight: 600;
    color: var(--color-gray-400);
    letter-spacing: 0.04em;
    text-transform: uppercase;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.psd-filter-label__count {
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--color-teal);
    font-weight: 500;
    text-transform: none;
    letter-spacing: 0;
}

.psd-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.psd-chip {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    border: 1px solid var(--color-white-a10);
    background-color: var(--color-white-a4);
    color: var(--color-gray-400);
    font-family: var(--font-body);
    font-size: 13px;
    font-weight: 400;
    padding: 8px 16px;
    border-radius: var(--border-radius-lg);
    cursor: pointer;
    transition: all 0.25s var(--ease-smooth);
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}

.psd-chip:hover {
    border-color: var(--color-white-a20);
    background: var(--color-white-a8);
    color: var(--color-gray-200);
}

.psd-chip.is-selected {
    border-color: var(--color-teal);
    background: var(--color-teal-a15);
    color: var(--color-teal);
}

/* --- Difficulty chips --- */
.psd-chip--easy.is-selected {
    border-color: var(--color-green);
    background: var(--color-green-a15);
    color: var(--color-green);
}

.psd-chip--medium.is-selected {
    border-color: var(--color-orange);
    background: var(--color-orange-a15);
    color: var(--color-orange);
}

.psd-chip--hard.is-selected {
    border-color: var(--color-red);
    background: var(--color-red-a12);
    color: var(--color-red);
}

/* --- Category stats grid --- */
.psd-cat-grid__label {
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 600;
    color: var(--color-gray-500);
    letter-spacing: 0.06em;
    text-transform: uppercase;
    margin-bottom: 10px;
}

.psd-cat-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    margin-top: 32px;
}

.psd-cat-card {
    background: var(--color-white-a2);
    border: 1px solid var(--color-white-a6);
    border-radius: var(--border-radius-sm);
    padding: 14px 16px;
    display: flex;
    align-items: center;
    gap: 12px;
    opacity: 0.75;
}

.psd-cat-card__icon {
    font-size: 20px;
    flex-shrink: 0;
}

.psd-cat-card__body {
    flex: 1;
    min-width: 0;
}

.psd-cat-card__name {
    font-family: var(--font-display);
    font-size: 13px;
    font-weight: 500;
    color: var(--color-gray-200);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.psd-cat-card__count {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--color-gray-500);
}

.psd-bank-status {
    grid-column: 1 / -1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
    padding: 32px 16px;
    text-align: center;
}

.psd-bank-status__text {
    margin: 0;
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--color-gray-500);
    letter-spacing: 0.02em;
}

.psd-bank-status--error .psd-bank-status__text {
    color: var(--color-red);
}

/* ============================================
   QUIZ SETUP SCREEN
   ============================================ */
.psd-setup__header {
    text-align: center;
    margin-bottom: 48px;
}

.psd-setup__title {
    font-family: var(--font-display);
    font-size: clamp(24px, 4vw, 32px);
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: 8px;
}

.psd-setup__subtitle {
    font-size: 15px;
    color: var(--color-gray-400);
    font-weight: 300;
}

.psd-size-options {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
    margin-bottom: 40px;
}

.psd-size-btn {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    background: var(--color-white-a4);
    border: 1.5px solid var(--color-white-a10);
    border-radius: var(--border-radius-md);
    padding: 20px 12px;
    text-align: center;
    cursor: pointer;
    transition: all 0.25s var(--ease-smooth);
    font-family: inherit;
    color: inherit;
}

.psd-size-btn:hover {
    border-color: var(--color-white-a20);
    background: var(--color-white-a8);
}

.psd-size-btn.is-selected {
    border-color: var(--color-teal);
    background: var(--color-teal-a12);
}

.psd-size-btn__num {
    font-family: var(--font-display);
    font-size: 28px;
    font-weight: 700;
    color: var(--color-gray-100);
    display: block;
    margin-bottom: 4px;
    letter-spacing: -0.02em;
}

.psd-size-btn.is-selected .psd-size-btn__num {
    color: var(--color-teal);
}

.psd-size-btn__label {
    font-size: 12px;
    color: var(--color-gray-500);
}

.psd-setup__toggle {
    display: flex;
    justify-content: center;
    margin-bottom: 32px;
}

.psd-toggle-label {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-size: 14px;
    color: var(--color-gray-400);
    cursor: pointer;
    user-select: none;
}

.psd-toggle {
    position: relative;
    display: inline-block;
    width: 40px;
    height: 22px;
    flex-shrink: 0;
}

.psd-toggle input {
    opacity: 0;
    width: 0;
    height: 0;
    position: absolute;
}

.psd-toggle__track {
    position: absolute;
    inset: 0;
    background: var(--color-white-a10);
    border-radius: 11px;
    transition: background 0.3s;
    cursor: pointer;
}

.psd-toggle__track::after {
    content: "";
    position: absolute;
    width: 18px;
    height: 18px;
    left: 2px;
    top: 2px;
    background: var(--color-gray-300);
    border-radius: 50%;
    transition: transform 0.3s, background 0.3s;
}

.psd-toggle input:checked + .psd-toggle__track {
    background: var(--color-teal-a25);
}

.psd-toggle input:checked + .psd-toggle__track::after {
    transform: translateX(18px);
    background: var(--color-teal);
}

.psd-setup__actions {
    display: flex;
    justify-content: center;
    gap: 12px;
}

.psd-btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 36px;
    border-radius: var(--border-radius-pill);
    border: none;
    background: var(--color-teal);
    color: #000;
    font-family: var(--font-display);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    letter-spacing: -0.01em;
    transition: all 0.3s var(--ease-smooth);
}

.psd-btn-primary:hover {
    transform: scale(1.04);
    filter: brightness(1.1);
}

.psd-btn-secondary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 32px;
    border-radius: var(--border-radius-pill);
    border: 1px solid var(--color-white-a12);
    background: transparent;
    color: var(--color-gray-200);
    font-family: var(--font-display);
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s var(--ease-smooth);
    letter-spacing: -0.01em;
    text-decoration: none;
}

.psd-btn-secondary:hover {
    background: var(--color-white-a6);
    border-color: var(--color-white-a20);
}

/* ============================================
   QUIZ SCREEN
   ============================================ */
.psd-quiz__progress {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 8px;
}

.psd-quiz__bar {
    flex: 1;
    height: 4px;
    background: var(--color-white-a8);
    border-radius: 2px;
    overflow: hidden;
}

.psd-quiz__fill {
    height: 100%;
    background: var(--color-teal);
    border-radius: 2px;
    transition: width 0.5s var(--ease-out-expo);
}

.psd-quiz__counter {
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 500;
    color: var(--color-gray-500);
    white-space: nowrap;
    flex-shrink: 0;
}

.psd-quiz__meta {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.psd-quiz__streak {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 600;
    color: var(--color-yellow);
    background: var(--color-yellow-a12);
    padding: 4px 10px;
    border-radius: var(--border-radius-pill);
}

.psd-quiz__streak:empty { display: none; }

.psd-badge {
    font-family: var(--font-mono);
    font-size: 10px;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    padding: 4px 10px;
    border-radius: var(--border-radius-pill);
}

.psd-badge--category {
    color: var(--color-teal);
    background: var(--color-teal-a12);
}

.psd-badge--easy {
    color: var(--color-green);
    background: var(--color-green-a12);
}

.psd-badge--medium {
    color: var(--color-orange);
    background: var(--color-orange-a12);
}

.psd-badge--hard {
    color: var(--color-red);
    background: var(--color-red-a12);
}

.psd-badge--multi {
    color: var(--color-purple);
    background: var(--color-purple-a12);
}

.psd-badge.is-hidden { display: none; }

.psd-quiz__bookmark {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    background: none;
    border: 1px solid transparent;
    color: var(--color-gray-600);
    cursor: pointer;
    padding: 4px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.25s;
    margin-left: auto;
}

.psd-quiz__bookmark:hover {
    color: var(--color-yellow);
    background: var(--color-yellow-a8);
}

.psd-quiz__bookmark.is-active {
    color: var(--color-yellow);
    background: var(--color-yellow-a12);
    border-color: var(--color-yellow);
}

.psd-quiz__bookmark.is-active svg { fill: var(--color-yellow); }

/* --- Question card --- */
.psd-qcard {
    background: var(--color-white-a4);
    border: 1px solid var(--color-white-a8);
    border-radius: var(--border-radius-lg);
    padding: 36px;
    margin-bottom: 24px;
    border-top: 3px solid var(--color-teal);
}

.psd-qcard__question {
    font-family: var(--font-display);
    font-size: clamp(18px, 3vw, 22px);
    font-weight: 600;
    line-height: 1.4;
    letter-spacing: -0.02em;
    color: var(--color-gray-50);
    margin-bottom: 24px;
}

/* --- Option buttons --- */
.psd-options {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 16px;
}

.psd-option {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    display: flex;
    align-items: flex-start;
    gap: 12px;
    width: 100%;
    text-align: left;
    padding: 14px 18px;
    border-radius: var(--border-radius-sm);
    border: 1.5px solid var(--color-white-a10);
    background: var(--color-white-a3);
    color: var(--color-gray-200);
    font-family: var(--font-body);
    font-size: 14px;
    line-height: 1.5;
    cursor: pointer;
    transition: all 0.2s var(--ease-smooth);
}

.psd-option:hover {
    border-color: var(--color-white-a20);
    background: var(--color-white-a6);
}

.psd-option__letter {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    min-width: 24px;
    border-radius: 50%;
    background: var(--color-white-a8);
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 600;
    color: var(--color-gray-400);
    flex-shrink: 0;
    transition: all 0.2s;
}

.psd-option__text {
    flex: 1;
    padding-top: 2px;
}

/* Multi-select: selected but not submitted */
.psd-option.is-multi-selected {
    border-color: var(--color-purple);
    background: var(--color-purple-a10);
}

.psd-option.is-multi-selected .psd-option__letter {
    background: var(--color-purple);
    color: #fff;
}

/* Correct answer */
.psd-option.is-correct {
    border-color: var(--color-green);
    background: var(--color-green-a10);
    cursor: default;
}

.psd-option.is-correct .psd-option__letter {
    background: var(--color-green);
    color: #fff;
}

/* Wrong answer */
.psd-option.is-wrong {
    border-color: var(--color-red);
    background: var(--color-red-a10);
    cursor: default;
}

.psd-option.is-wrong .psd-option__letter {
    background: var(--color-red);
    color: #fff;
}

/* Disabled (after answering) */
.psd-option.is-disabled {
    opacity: 0.5;
    cursor: default;
    pointer-events: none;
}

/* --- Confirm button (multi-select) --- */
.psd-confirm-wrap {
    text-align: center;
    margin-bottom: 16px;
}

.psd-confirm-wrap.is-hidden { display: none; }

.psd-btn-confirm {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 28px;
    border-radius: var(--border-radius-pill);
    border: none;
    background: var(--color-purple);
    color: #fff;
    font-family: var(--font-display);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s var(--ease-smooth);
}

.psd-btn-confirm:hover {
    transform: scale(1.04);
    filter: brightness(1.1);
}

.psd-btn-confirm:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    transform: none;
}

/* --- Explanation panel --- */
.psd-explanation {
    display: none;
    background: var(--color-white-a3);
    border: 1px solid var(--color-white-a8);
    border-radius: var(--border-radius-sm);
    padding: 20px;
    margin-top: 16px;
    animation: screen-in 0.3s var(--ease-out-expo);
}

.psd-explanation.is-visible { display: block; }

.psd-explanation__text {
    font-size: 14px;
    line-height: 1.65;
    color: var(--color-gray-300);
    margin-bottom: 12px;
}

.psd-explanation__tip {
    font-size: 13px;
    line-height: 1.5;
    color: var(--color-gray-400);
    padding: 10px 14px;
    border-left: 3px solid var(--color-orange);
    background: var(--color-orange-a8);
    border-radius: 0 var(--border-radius-sm) var(--border-radius-sm) 0;
    margin-bottom: 10px;
}

.psd-explanation__source {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--color-gray-500);
}

/* --- Quiz next button --- */
.psd-quiz__next-wrap {
    display: none;
    text-align: center;
    margin-top: 20px;
}

.psd-quiz__next-wrap.is-visible { display: block; }

/* ============================================
   RESULTS SCREEN
   ============================================ */
.psd-results__header {
    text-align: center;
    margin-bottom: 40px;
}

.psd-results__ring {
    width: 160px;
    height: 160px;
    margin: 0 auto 24px;
    position: relative;
}

.psd-results__ring svg {
    width: 100%;
    height: 100%;
    transform: rotate(-90deg);
}

.psd-results__ring-bg {
    fill: none;
    stroke: var(--color-white-a8);
    stroke-width: 4;
}

.psd-results__ring-fill {
    fill: none;
    stroke: var(--color-teal);
    stroke-width: 4;
    stroke-linecap: round;
    transition: stroke-dashoffset 1.2s var(--ease-out-expo);
}

.psd-results__ring-text {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.psd-results__pct {
    font-family: var(--font-display);
    font-size: 40px;
    font-weight: 700;
    letter-spacing: -0.03em;
    color: var(--color-gray-50);
}

.psd-results__grade {
    font-family: var(--font-mono);
    font-size: 13px;
    font-weight: 600;
    color: var(--color-teal);
}

.psd-results__title {
    font-family: var(--font-display);
    font-size: clamp(22px, 4vw, 28px);
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: 8px;
}

.psd-results__subtitle {
    font-size: 15px;
    color: var(--color-gray-400);
    font-weight: 300;
}

/* --- Stats row --- */
.psd-results__stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin-bottom: 32px;
}

.psd-results__stat {
    background: var(--color-white-a4);
    border: 1px solid var(--color-white-a8);
    border-radius: var(--border-radius-md);
    padding: 20px;
    text-align: center;
}

.psd-results__stat-value {
    font-family: var(--font-display);
    font-size: 24px;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 4px;
}

.psd-results__stat-value--green { color: var(--color-green); }
.psd-results__stat-value--red { color: var(--color-red); }
.psd-results__stat-value--teal { color: var(--color-teal); }

.psd-results__stat-label {
    font-size: 12px;
    color: var(--color-gray-500);
}

/* --- Category breakdown --- */
.psd-breakdown {
    background: var(--color-white-a4);
    border: 1px solid var(--color-white-a8);
    border-radius: var(--border-radius-lg);
    padding: 28px;
    margin-bottom: 32px;
}

.psd-breakdown__title {
    font-family: var(--font-display);
    font-size: 15px;
    font-weight: 600;
    color: var(--color-gray-200);
    margin-bottom: 20px;
}

.psd-breakdown__row {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 10px 0;
    border-bottom: 1px solid var(--color-white-a6);
}

.psd-breakdown__row:last-child { border-bottom: none; }

.psd-breakdown__name {
    font-family: var(--font-display);
    font-size: 13px;
    font-weight: 500;
    color: var(--color-gray-200);
    min-width: 140px;
    flex-shrink: 0;
}

.psd-breakdown__bar {
    flex: 1;
    height: 6px;
    background: var(--color-white-a6);
    border-radius: 3px;
    overflow: hidden;
}

.psd-breakdown__fill {
    width: 0;
    height: 100%;
    border-radius: 3px;
    background: var(--color-teal);
    transition: width 0.8s var(--ease-out-expo);
}

.psd-breakdown__fill--green { background: var(--color-green); }

.psd-breakdown__fill--teal { background: var(--color-teal); }

.psd-breakdown__fill--orange { background: var(--color-orange); }

.psd-breakdown__fill--red { background: var(--color-red); }

.psd-breakdown__pct {
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 500;
    color: var(--color-gray-400);
    min-width: 36px;
    text-align: right;
}

/* --- Full answer log (results) --- */
.psd-answer-log {
    background: var(--color-white-a4);
    border: 1px solid var(--color-white-a8);
    border-radius: var(--border-radius-lg);
    padding: 28px;
    margin-bottom: 32px;
}

.psd-answer-log__top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
    flex-wrap: wrap;
    gap: 12px;
}

.psd-answer-log__title {
    font-family: var(--font-display);
    font-size: 15px;
    font-weight: 600;
    color: var(--color-gray-200);
}

.psd-answer-log__tabs {
    display: flex;
    gap: 6px;
}

.psd-answer-log__tab {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    border: 1px solid var(--color-white-a10);
    background: var(--color-white-a4);
    color: var(--color-gray-400);
    font-family: var(--font-display);
    font-size: 12px;
    font-weight: 500;
    padding: 5px 12px;
    border-radius: var(--border-radius-pill);
    cursor: pointer;
    transition: all 0.25s var(--ease-smooth);
}

.psd-answer-log__tab:hover {
    border-color: var(--color-white-a20);
    color: var(--color-gray-200);
}

.psd-answer-log__tab.is-active {
    border-color: var(--color-teal);
    background: var(--color-teal-a15);
    color: var(--color-teal);
}

.psd-answer-log__item {
    border-bottom: 1px solid var(--color-white-a6);
}

.psd-answer-log__item:last-child { border-bottom: none; }

.psd-answer-log__header {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    padding: 12px 0;
    cursor: pointer;
    user-select: none;
}

.psd-answer-log__header:hover { opacity: 0.85; }

.psd-answer-log__status {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 22px;
    height: 22px;
    min-width: 22px;
    border-radius: 50%;
    font-size: 11px;
    font-weight: 700;
    flex-shrink: 0;
    margin-top: 1px;
}

.psd-answer-log__status--correct {
    background: var(--color-green-a15);
    color: var(--color-green);
}

.psd-answer-log__status--wrong {
    background: var(--color-red-a12);
    color: var(--color-red);
}

.psd-answer-log__q {
    flex: 1;
    font-family: var(--font-display);
    font-size: 13px;
    font-weight: 500;
    color: var(--color-gray-200);
    line-height: 1.4;
}

.psd-answer-log__chevron {
    width: 16px;
    height: 16px;
    color: var(--color-gray-600);
    flex-shrink: 0;
    transition: transform 0.3s var(--ease-smooth);
    margin-top: 3px;
}

.psd-answer-log__item.is-open .psd-answer-log__chevron {
    transform: rotate(180deg);
}

.psd-answer-log__body {
    display: none;
    padding: 0 0 14px 32px;
    animation: screen-in 0.3s var(--ease-out-expo);
}

.psd-answer-log__item.is-open .psd-answer-log__body { display: block; }

.psd-answer-log__options {
    display: flex;
    flex-direction: column;
    gap: 5px;
    margin-bottom: 12px;
}

.psd-answer-log__opt {
    display: flex;
    align-items: flex-start;
    gap: 8px;
    font-size: 13px;
    line-height: 1.5;
    color: var(--color-gray-400);
    padding: 5px 10px;
    border-radius: 8px;
    border: 1px solid transparent;
}

.psd-answer-log__opt--user-wrong {
    background: var(--color-red-a10);
    border-color: var(--color-red);
    color: var(--color-gray-200);
}

.psd-answer-log__opt--correct {
    background: var(--color-green-a10);
    border-color: var(--color-green);
    color: var(--color-gray-200);
}

.psd-answer-log__opt-marker {
    font-size: 12px;
    flex-shrink: 0;
    padding-top: 1px;
    min-width: 16px;
}

.psd-answer-log__explanation {
    font-size: 13px;
    line-height: 1.6;
    color: var(--color-gray-400);
    padding: 10px 14px;
    border-left: 3px solid var(--color-teal);
    background: var(--color-teal-a6);
    border-radius: 0 var(--border-radius-sm) var(--border-radius-sm) 0;
}

/* --- Results actions --- */
.psd-results__actions {
    display: flex;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
}

/* ============================================
   FLASHCARDS SCREEN
   ============================================ */
.psd-study__progress {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 24px;
}

.psd-study__bar {
    flex: 1;
    height: 4px;
    background: var(--color-white-a8);
    border-radius: 2px;
    overflow: hidden;
}

.psd-study__fill {
    height: 100%;
    background: var(--color-teal);
    border-radius: 2px;
    transition: width 0.5s var(--ease-out-expo);
}

.psd-study__counter {
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 500;
    color: var(--color-gray-500);
    white-space: nowrap;
    flex-shrink: 0;
}

/* --- Flashcard --- */
.psd-flashcard {
    background: var(--color-white-a4);
    border: 1px solid var(--color-white-a8);
    border-radius: var(--border-radius-lg);
    padding: 36px;
    margin-bottom: 24px;
    min-height: 280px;
    cursor: pointer;
    transition: border-color 0.3s;
    border-top: 3px solid var(--color-teal);
}

.psd-flashcard:hover {
    border-color: var(--color-white-a15);
}

.psd-flashcard__meta {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.psd-flashcard__question {
    font-family: var(--font-display);
    font-size: clamp(18px, 3vw, 22px);
    font-weight: 600;
    line-height: 1.4;
    letter-spacing: -0.02em;
    color: var(--color-gray-50);
    margin-bottom: 20px;
}

/* Options always visible in flashcard; correct marking hidden until reveal */
.psd-flashcard__options-always {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 16px;
}

.psd-flashcard__reveal-hint {
    font-size: 13px;
    color: var(--color-gray-600);
    text-align: center;
    padding: 8px;
    transition: opacity 0.3s;
}

.psd-flashcard__answer {
    display: none;
    animation: screen-in 0.3s var(--ease-out-expo);
}

.psd-flashcard__answer.is-visible { display: block; }

.psd-flashcard__options {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 16px;
}

.psd-flashcard__opt {
    padding: 10px 14px;
    border-radius: var(--border-radius-sm);
    font-size: 14px;
    line-height: 1.5;
    color: var(--color-gray-400);
    background: var(--color-white-a3);
    border: 1px solid var(--color-white-a6);
    display: flex;
    align-items: flex-start;
    gap: 10px;
}

.psd-flashcard__opt.is-correct {
    background: var(--color-green-a10);
    border-color: var(--color-green);
    color: var(--color-gray-200);
}

.psd-flashcard__opt-letter {
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 600;
    color: var(--color-gray-500);
    min-width: 18px;
    padding-top: 2px;
}

.psd-flashcard__opt.is-correct .psd-flashcard__opt-letter {
    color: var(--color-green);
}

/* --- Flashcard nav --- */
.psd-study__nav {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
}

.psd-study__nav-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: var(--border-radius-pill);
    border: 1px solid var(--color-white-a12);
    background: transparent;
    color: var(--color-gray-300);
    font-family: var(--font-display);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.25s var(--ease-smooth);
}

.psd-study__nav-btn:hover {
    background: var(--color-white-a6);
    border-color: var(--color-white-a20);
}

.psd-study__nav-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

.psd-study__nav-btn svg {
    width: 16px;
    height: 16px;
}

.psd-study__back-wrap {
    text-align: center;
    margin-top: 24px;
}

/* ============================================
   REVIEW SCREEN
   ============================================ */
.psd-review__header {
    margin-bottom: 32px;
}

.psd-review__title {
    font-family: var(--font-display);
    font-size: clamp(22px, 4vw, 28px);
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: 8px;
}

.psd-review__subtitle {
    font-size: 14px;
    color: var(--color-gray-400);
    font-weight: 300;
}

.psd-review__controls {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 24px;
}

/* --- Search input --- */
.psd-review__search {
    position: relative;
    width: 100%;
}

.psd-review__search-icon {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--color-gray-600);
    pointer-events: none;
    transition: color 0.25s;
}

.psd-review__search:focus-within .psd-review__search-icon {
    color: var(--color-teal);
}

.psd-review__search-input {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    width: 100%;
    padding: 8px 14px 8px 34px;
    border-radius: var(--border-radius-pill);
    border: 1px solid var(--color-white-a10);
    background: var(--color-white-a4);
    color: var(--color-gray-200);
    font-family: var(--font-body);
    font-size: 13px;
    outline: none;
    transition: border-color 0.25s, background 0.25s;
}

.psd-review__search-input::placeholder {
    color: var(--color-gray-600);
}

.psd-review__search-input:focus {
    border-color: var(--color-teal);
    background: var(--color-teal-a6);
}

/* --- Toolbar --- */
.psd-review__toolbar {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
    flex-wrap: wrap;
}

.psd-review__toolbar-left {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.psd-review__toolbar-right {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

/* --- Custom select --- */
.psd-review__select {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    padding: 8px 32px 8px 12px;
    border-radius: var(--border-radius-pill);
    border: 1px solid var(--color-white-a10);
    background-color: var(--color-white-a4);
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23999' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 10px center;
    color: var(--color-gray-300);
    font-family: var(--font-body);
    font-size: 13px;
    cursor: pointer;
    outline: none;
    transition: border-color 0.25s, background-color 0.25s;
}

.psd-review__select:hover {
    border-color: var(--color-white-a20);
    background-color: var(--color-white-a6);
}

.psd-review__select:focus {
    border-color: var(--color-teal);
    background-color: var(--color-teal-a6);
}

.psd-review__select option {
    background: #1a1a2e;
    color: var(--color-gray-200);
}

/* --- Info bar --- */
.psd-review__info {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 0;
    border-top: 1px solid var(--color-white-a6);
    border-bottom: 1px solid var(--color-white-a6);
}

.psd-review__info-count {
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 600;
    color: var(--color-teal);
}

.psd-review__info-range {
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--color-gray-500);
}

/* --- Pagination --- */
.psd-review__pagination {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 4px;
    margin-top: 24px;
    flex-wrap: wrap;
}

.psd-review__pagination:empty {
    display: none;
}

.psd-pag-btn {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    width: 36px;
    height: 36px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--border-radius-sm);
    border: 1px solid var(--color-white-a10);
    background: var(--color-white-a4);
    color: var(--color-gray-300);
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s var(--ease-smooth);
}

.psd-pag-btn:hover {
    border-color: var(--color-teal);
    background: var(--color-teal-a10);
    color: var(--color-teal);
}

.psd-pag-btn.is-active {
    border-color: var(--color-teal);
    background: var(--color-teal-a20);
    color: var(--color-teal);
    font-weight: 700;
}

.psd-pag-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
    pointer-events: none;
}

.psd-pag-btn--arrow {
    width: auto;
    padding: 0 12px;
    gap: 4px;
    font-family: var(--font-display);
    font-size: 13px;
    font-weight: 500;
}

.psd-pag-ellipsis {
    width: 36px;
    height: 36px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    color: var(--color-gray-600);
    font-family: var(--font-mono);
    font-size: 14px;
}

.psd-review__list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.psd-review__item {
    background: var(--color-white-a3);
    border: 1px solid var(--color-white-a8);
    border-radius: var(--border-radius-sm);
    transition: transform 0.3s var(--ease-smooth),
                border-color 0.3s,
                background 0.3s,
                box-shadow 0.3s;
}

.psd-review__item:hover {
    transform: translateY(-2px);
    border-color: var(--color-white-a12);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.12);
}

.psd-review__item.is-open {
    border-color: var(--color-teal-a25);
}

/* --- Smooth expand/collapse (CSS Grid) --- */
.psd-review__item-collapse {
    display: grid;
    grid-template-rows: 0fr;
    transition: grid-template-rows 0.45s var(--ease-smooth);
}

.psd-review__item.is-open .psd-review__item-collapse {
    grid-template-rows: 1fr;
}

.psd-review__item-collapse-inner {
    overflow: hidden;
}

.psd-review__item-body {
    padding: 0 18px 16px 54px;
}

/* --- Header --- */
.psd-review__item-header {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 18px;
    cursor: pointer;
    transition: background 0.2s;
    user-select: none;
}

.psd-review__item-header:hover {
    background: var(--color-white-a4);
}

/* --- Number circle --- */
.psd-review__item-num {
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 600;
    color: var(--color-teal);
    background: var(--color-teal-a12);
    width: 28px;
    height: 28px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.psd-review__item-num--wide {
    width: auto;
    min-width: 28px;
    padding: 0 8px;
    border-radius: var(--border-radius-pill);
}

.psd-review__item-q {
    flex: 1;
    font-family: var(--font-display);
    font-size: 14px;
    font-weight: 500;
    color: var(--color-gray-200);
    line-height: 1.4;
}

.psd-review__item-badges {
    display: flex;
    gap: 6px;
    flex-shrink: 0;
    flex-wrap: wrap;
}

.psd-review__bookmark {
    margin-left: 0;
    flex-shrink: 0;
}

/* --- Chevron --- */
.psd-review__item-chevron {
    width: 16px;
    height: 16px;
    color: var(--color-gray-600);
    flex-shrink: 0;
    transition: transform 0.45s var(--ease-smooth), color 0.3s;
}

.psd-review__item.is-open .psd-review__item-chevron {
    transform: rotate(180deg);
    color: var(--color-teal);
}

.psd-review__item-header:hover .psd-review__item-chevron {
    color: var(--color-teal);
}

/* --- Answer list --- */
.psd-review__answer-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 12px;
}

.psd-review__answer {
    font-size: 13px;
    line-height: 1.5;
    color: var(--color-gray-400);
    padding: 6px 10px;
    border-radius: 8px;
    display: flex;
    align-items: flex-start;
    gap: 8px;
    border: 1px solid transparent;
    transition: background 0.3s, border-color 0.3s, color 0.3s;
}

.psd-review__answer:hover {
    background: var(--color-white-a4);
    border-color: var(--color-white-a8);
}

.psd-review__answer.is-correct {
    background: var(--color-green-a10);
    border-color: var(--color-green-a20);
    color: var(--color-gray-200);
}

/* --- SVG answer markers --- */
.psd-review__answer-marker {
    position: relative;
    width: 16px;
    height: 16px;
    flex-shrink: 0;
    margin-top: 2px;
}

.psd-review__marker-circle,
.psd-review__marker-check {
    position: absolute;
    top: 0;
    left: 0;
    width: 16px;
    height: 16px;
    transition: opacity 0.3s var(--ease-smooth), transform 0.3s var(--ease-smooth);
}

.psd-review__marker-check {
    opacity: 0;
    transform: scale(0.5);
}

.psd-review__answer.is-correct .psd-review__marker-circle {
    opacity: 0;
    transform: scale(0.5);
}

.psd-review__answer.is-correct .psd-review__marker-check {
    opacity: 1;
    transform: scale(1.15);
    color: var(--color-green);
}

/* --- Explanation block --- */
.psd-review__explanation-collapse {
    display: grid;
    grid-template-rows: 0fr;
    transition: grid-template-rows 0.45s var(--ease-smooth);
}

.psd-review__explanation-collapse.is-open {
    grid-template-rows: 1fr;
}

.psd-review__explanation-collapse-inner {
    overflow: hidden;
}

.psd-review__explanation {
    padding: 12px 14px;
    border-left: 3px solid var(--color-teal);
    background: var(--color-teal-a6);
    border-radius: 0 var(--border-radius-sm) var(--border-radius-sm) 0;
}

.psd-review__explanation-label {
    font-family: var(--font-mono);
    font-size: 10px;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--color-teal);
    margin-bottom: 6px;
}

.psd-review__explanation-text {
    font-size: 13px;
    line-height: 1.6;
    color: var(--color-gray-400);
}

.psd-review__tip {
    font-size: 12px;
    line-height: 1.5;
    color: var(--color-orange);
    padding: 8px 12px;
    border-left: 3px solid var(--color-orange);
    background: var(--color-orange-a8);
    border-radius: 0 var(--border-radius-sm) var(--border-radius-sm) 0;
    margin-top: 10px;
}

.psd-review__source {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--color-gray-600);
    margin-top: 8px;
}

/* --- Back link (reusable) --- */
.psd-back-link {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    display: inline-flex;
    align-items: center;
    gap: 4px;
    color: var(--color-teal);
    font-family: var(--font-display);
    font-size: 14px;
    font-weight: 500;
    background: none;
    border: none;
    padding: 0;
    cursor: pointer;
    margin-bottom: 16px;
}

.psd-back-link:hover { opacity: 0.75; }

/* --- Review reveal button --- */
.psd-review__reveal-btn {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    border-radius: var(--border-radius-pill);
    border: 1px solid var(--color-white-a12);
    background: transparent;
    color: var(--color-gray-400);
    font-family: var(--font-display);
    font-size: 12px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.25s var(--ease-smooth);
    margin-bottom: 12px;
}

.psd-review__reveal-btn:hover {
    background: var(--color-teal-a10);
    border-color: var(--color-teal);
    color: var(--color-teal);
}

.psd-review__reveal-btn.is-revealed {
    background: var(--color-teal-a10);
    border-color: var(--color-teal);
    color: var(--color-teal);
    pointer-events: none;
}

.psd-review__reveal-icon {
    transition: opacity 0.25s, width 0.25s;
}

.psd-review__reveal-btn.is-revealed .psd-review__reveal-icon {
    opacity: 0;
    width: 0;
    overflow: hidden;
}

.psd-review__back-wrap {
    margin-top: 32px;
    text-align: center;
}

/* ============================================
   BOOKMARK FILTER
   ============================================ */
.psd-bookmark-filter {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 16px;
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--color-white-a10);
    background: var(--color-white-a4);
    color: var(--color-gray-400);
    font-family: var(--font-body);
    font-size: 13px;
    cursor: pointer;
    transition: all 0.25s var(--ease-smooth);
}

.psd-bookmark-filter:hover {
    border-color: var(--color-yellow-a40);
    color: var(--color-yellow);
}

.psd-bookmark-filter.is-active {
    border-color: var(--color-yellow);
    background: var(--color-yellow-a12);
    color: var(--color-yellow);
}

/* ============================================
   RESPONSIVE — Tablet
   ============================================ */
@media (max-width: 768px) {
    .psd-modes { grid-template-columns: 1fr; gap: 10px; }
    .psd-mode-card { padding: 20px 18px; text-align: left; display: flex; align-items: center; gap: 16px; }
    .psd-mode-card__icon { font-size: 28px; margin-bottom: 0; }
    .psd-size-options { grid-template-columns: repeat(2, 1fr); }
    .psd-cat-grid { grid-template-columns: 1fr; }
    .psd-qcard { padding: 28px; }
    .psd-flashcard { padding: 28px; }
    .psd-breakdown { padding: 24px 20px; }
    .psd-answer-log { padding: 24px 20px; }
    .psd-breakdown__name { min-width: 100px; }
    .psd-review__toolbar { flex-direction: column; }
    .psd-review__toolbar-left { display: grid; grid-template-columns: repeat(2, 1fr); width: 100%; }
    .psd-review__toolbar-right { flex-direction: row; flex-wrap: wrap; }
}

/* ============================================
   RESPONSIVE — Mobile
   ============================================ */
@media (max-width: 640px) {
    .psd-hero { margin-bottom: 36px; }
    .psd-size-options { grid-template-columns: repeat(2, 1fr); gap: 8px; }
    .psd-size-btn { padding: 16px 10px; }
    .psd-size-btn__num { font-size: 24px; }
    .psd-qcard { padding: 24px; }
    .psd-flashcard { padding: 24px; min-height: 220px; }
    .psd-option { padding: 12px 14px; font-size: 13px; }
    .psd-results__stats { grid-template-columns: 1fr; }
    .psd-results__ring { width: 130px; height: 130px; }
    .psd-results__pct { font-size: 32px; }
    .psd-results__actions { flex-direction: column; align-items: center; }
    .psd-breakdown__row { flex-direction: column; gap: 6px; align-items: stretch; }
    .psd-breakdown__name { min-width: auto; }
    .psd-breakdown__pct { text-align: left; }
    .psd-review__item-badges .psd-review__diff-badge { display: none; }
    .psd-review__item-badges .psd-badge--category { display: none; }
    .psd-study__nav { gap: 10px; }
    .psd-study__nav-btn { padding: 10px 18px; font-size: 13px; }
    .psd-setup__actions { flex-direction: column; align-items: center; }
    .psd-review__toolbar-left { grid-template-columns: 1fr; }
    .psd-review__toolbar-right { flex-direction: column; }
    .psd-review__select { width: 100%; }
}