/* ── Page layout (shared by practice & exam) ─────────────────────────── */
.ex-page { padding: 0 0 64px; min-height: calc(100vh - 100px); }

/* ── Top bar ──────────────────────────────────────────────────────────── */
.pr-topbar { margin-top: -64px; padding: 78px 0 14px; color: #fff; }
.pr-topbar .pk-container { display: flex; align-items: center; gap: 20px; }
.pr-back { color: rgba(255,255,255,0.85); font-weight: 700; font-size: 14px; }
.pr-back:hover { color: #fff; }
.pr-meta { display: flex; gap: 8px; }
.pr-badge { padding: 3px 12px; border-radius: 20px; background: rgba(255,255,255,0.2); font-size: 13px; font-weight: 700; }

/* ── Steps ────────────────────────────────────────────────────────────── */
.pr-steps { display: flex; align-items: center; justify-content: center; padding: 16px 0 0; gap: 0; }
.pr-step { display: flex; align-items: center; gap: 8px; padding: 6px 14px; }
.pr-step-num {
    width: 26px; height: 26px; border-radius: 50%; background: #eee; color: #999;
    font-size: 12px; font-weight: 800; display: flex; align-items: center; justify-content: center;
}
.pr-step-label { font-size: 13px; font-weight: 600; color: #999; }
.pr-step--active .pr-step-num { background: var(--pk-coral); color: #fff; }
.pr-step--active .pr-step-label { color: var(--pk-coral); font-weight: 800; }
.pr-step--done .pr-step-num { background: var(--pk-mint); color: #fff; }
.pr-step--done .pr-step-label { color: var(--pk-mint); }
.pr-step-line { flex: 0 0 36px; height: 2px; background: #eee; }

/* ── Difficulty ───────────────────────────────────────────────────────── */
.pr-diff-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 14px; }
.pr-diff-card {
    display: flex; flex-direction: column; align-items: flex-start; gap: 6px;
    background: #fff; border-radius: 16px; padding: 24px 20px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.04); border: 2px solid transparent;
    cursor: pointer; transition: all 0.2s; font-family: var(--pk-font); text-align: left;
}
.pr-diff-card:hover { border-color: var(--dc); transform: translateY(-2px); box-shadow: 0 6px 24px rgba(0,0,0,0.08); }
.pr-diff-icon { font-size: 32px; }
.pr-diff-name { font-size: 17px; font-weight: 800; color: var(--pk-text); }
.pr-diff-desc { font-size: 12px; color: var(--pk-text-soft); line-height: 1.5; }

/* ── Topics ───────────────────────────────────────────────────────────── */
.pr-topic-grid { display: flex; gap: 10px; flex-wrap: wrap; }
.pr-topic-chip {
    padding: 10px 22px; border-radius: var(--pk-radius-pill);
    font-family: var(--pk-font); font-size: 15px; font-weight: 700;
    color: var(--pk-text-soft); background: #fff; border: 2px solid #eee;
    cursor: pointer; transition: all 0.2s;
}
.pr-topic-chip:hover { border-color: var(--pk-sky); }
.pr-topic-chip--on { background: var(--pk-sky); color: #fff; border-color: var(--pk-sky); }

/* ── Question ─────────────────────────────────────────────────────────── */
/* Step card wrapper */
.pr-step-card { background: #fff; border-radius: 20px; padding: 36px 32px; box-shadow: 0 2px 16px rgba(0,0,0,0.04); }

.pr-progress { margin-top: 12px; margin-bottom: 36px; }
.pr-progress-text { font-size: 14px; color: var(--pk-text-soft); display: block; margin-bottom: 8px; }
.pr-bar { height: 6px; background: #eee; border-radius: 3px; overflow: hidden; }
.pr-bar-fill { height: 100%; border-radius: 3px; transition: width 0.3s; background: var(--pk-primary, #4D96FF); }

.pr-card { background: #fff; border-radius: 20px; padding: 36px 32px; box-shadow: 0 2px 16px rgba(0,0,0,0.04); }
.pr-q-num { font-size: 13px; color: var(--pk-text-soft); font-weight: 700; }
.pr-question { font-size: 22px; font-weight: 800; margin: 16px 0 28px; line-height: 1.5; }
/* Rich content inside question title */
.pr-question img { max-width: 100%; height: auto; border-radius: 8px; margin: 8px 0; }
.pr-question table { border-collapse: collapse; width: 100%; margin: 8px 0; font-size: 15px; }
.pr-question th, .pr-question td { border: 1px solid #ddd; padding: 8px 12px; text-align: left; }
.pr-question th { background: #f5f5f5; font-weight: 700; }
.pr-question code { background: #f0f0f0; padding: 2px 6px; border-radius: 4px; font-size: 0.9em; font-family: 'SF Mono', 'Fira Code', monospace; }
.pr-question pre { background: #f5f5f5; padding: 12px 16px; border-radius: 8px; overflow-x: auto; font-size: 14px; line-height: 1.5; }
.pr-question pre code { background: none; padding: 0; }
.pr-question blockquote { border-left: 3px solid var(--pk-sky); margin: 8px 0; padding: 4px 16px; color: var(--pk-text-soft); }
.pr-question .katex-display { margin: 12px 0; }
.pr-question .katex { font-size: 1.1em; }

.pr-options { display: flex; flex-direction: column; gap: 12px; }
.pr-option {
    width: 100%; text-align: left; padding: 16px 20px; border: 2px solid #eee;
    border-radius: 12px; background: #fafafa; font-family: var(--pk-font);
    font-size: 16px; font-weight: 700; cursor: pointer; transition: all 0.2s;
    line-height: 1.6;
}
/* Rich content inside option buttons */
.pr-option img { max-width: 100%; height: auto; border-radius: 6px; margin: 4px 0; display: block; }
.pr-option .katex { font-size: 1.05em; }
.pr-option .katex-display { margin: 6px 0; }
.pr-option code { background: rgba(0,0,0,0.06); padding: 1px 5px; border-radius: 3px; font-size: 0.9em; }
.pr-option table { border-collapse: collapse; width: 100%; margin: 4px 0; font-size: 14px; }
.pr-option th, .pr-option td { border: 1px solid #ddd; padding: 4px 8px; text-align: left; }
.pr-option th { background: #f5f5f5; }
.pr-option p { margin: 4px 0; }
/* Option flag letter */
.pr-option-flag { font-weight: 900; color: var(--pk-coral); margin-right: 2px; }
.pr-option:hover:not(:disabled) { border-color: var(--pk-sky); background: #f0f7ff; }
.pr-option:disabled { cursor: default; }
.pr-option--selected { border-color: var(--pk-sky); background: #e3f2fd; box-shadow: 0 0 0 2px rgba(77,150,255,0.25); }
.pr-option--ok { border-color: var(--pk-mint); background: #e8f5e9; }
.pr-option--err { border-color: var(--pk-coral); background: #fce4ec; }

.pr-result { margin-top: 24px; padding-top: 24px; border-top: 1px solid #eee; text-align: center; }
.pr-result-icon { width: 48px; height: 48px; border-radius: 50%; color: #fff; font-size: 24px; font-weight: 900; display: flex; align-items: center; justify-content: center; margin: 0 auto 12px; }
.pr-result p { font-size: 16px; font-weight: 700; margin-bottom: 16px; }

/* ── Extra requirements ────────────────────────────────────────────────── */
.pr-extra-input:focus { outline: none; border-color: var(--pk-coral) !important; }
.pr-extra-btns { display: flex; gap: 14px; margin-top: 20px; flex-wrap: wrap; }

/* ── Loading / animation ────────────────────────────────────────────────── */

/* ── Orb loader (replaces spinner) ──────────────────────────────────────── */
@keyframes pr-orb-pulse {
    0%, 100% { transform: scale(0.95); box-shadow: 0 0 20px rgba(255,107,107,0.3), 0 0 60px rgba(255,107,107,0.1); }
    50%      { transform: scale(1.05); box-shadow: 0 0 40px rgba(255,107,107,0.5), 0 0 80px rgba(255,107,107,0.2); }
}
@keyframes pr-ring-orbit {
    from { transform: translate(-50%,-50%) rotate(0deg); }
    to   { transform: translate(-50%,-50%) rotate(360deg); }
}
@keyframes pr-ring-orbit-rev {
    from { transform: translate(-50%,-50%) rotate(0deg); }
    to   { transform: translate(-50%,-50%) rotate(-360deg); }
}
.pr-orb-loader {
    width: 80px; height: 80px; margin: 0 auto 24px; position: relative;
}
.pr-orb-core {
    width: 32px; height: 32px; border-radius: 50%;
    background: linear-gradient(135deg, var(--pk-coral), #ff8a80);
    position: absolute; top: 50%; left: 50%; transform: translate(-50%,-50%);
    animation: pr-orb-pulse 2s ease-in-out infinite;
    z-index: 2;
}
.pr-orb-ring {
    position: absolute; top: 50%; left: 50%; border-radius: 50%;
    border: 2px solid transparent;
    border-top-color: var(--pk-coral);
    animation: pr-ring-orbit 3s linear infinite;
}
.pr-orb-ring:nth-child(2) { width: 50px; height: 50px; animation-duration: 3s; opacity: 0.8; }
.pr-orb-ring:nth-child(3) { width: 65px; height: 65px; animation-duration: 4s; animation-direction: reverse; border-top-color: var(--pk-sky); opacity: 0.5; }
.pr-orb-ring:nth-child(4) { width: 80px; height: 80px; animation-duration: 5s; border-top-color: #ffd93d; opacity: 0.3; }

/* ── Floating symbols (loading particles) ────────────────────────────────── */
@keyframes pr-float-up {
    0%   { opacity: 0; transform: translateY(40px) scale(0.5) rotate(0deg); }
    20%  { opacity: 1; }
    80%  { opacity: 1; }
    100% { opacity: 0; transform: translateY(-80px) scale(1.2) rotate(25deg); }
}
.pr-floating-symbols {
    position: relative; height: 60px; overflow: hidden; margin-bottom: 8px;
    pointer-events: none;
}
.pr-float-sym {
    position: absolute; bottom: -10px;
    font-size: 20px; font-weight: 800;
    animation: pr-float-up 2.5s ease-out infinite;
}
.pr-float-sym:nth-child(1) { left: 15%; animation-delay: 0s; color: var(--pk-coral); }
.pr-float-sym:nth-child(2) { left: 35%; animation-delay: 0.6s; color: var(--pk-sky); }
.pr-float-sym:nth-child(3) { left: 55%; animation-delay: 1.2s; color: var(--pk-mint); }
.pr-float-sym:nth-child(4) { left: 75%; animation-delay: 1.8s; color: #ffd93d; }
.pr-float-sym:nth-child(5) { left: 50%; animation-delay: 2.2s; color: #9b59b6; font-size: 16px; }

/* ── Bouncing dots (text loader) ────────────────────────────────────────── */
@keyframes pr-bounce {
    0%, 80%, 100% { transform: scale(0); }
    40% { transform: scale(1); }
}
.pr-dot { display: inline-block; width: 8px; height: 8px; border-radius: 50%; background: var(--pk-coral); margin: 0 3px; animation: pr-bounce 1.4s ease-in-out infinite both; }
.pr-dot:nth-child(2) { animation-delay: 0.16s; }
.pr-dot:nth-child(3) { animation-delay: 0.32s; }

/* Loading message area */
.pr-loading-box { text-align: center; padding: 8px 20px 24px; }
.pr-loading-box .pr-loading-text { font-size: 15px; color: var(--pk-text-soft); font-weight: 600; }
.pr-loading-box .pr-loading-sub { font-size: 13px; color: var(--pk-text-soft); margin-top: 6px; opacity: 0.7; }

/* ── Confetti (correct answer) ───────────────────────────────────────────── */
@keyframes pr-confetti-fall {
    0%   { transform: translateY(0) rotate(0deg) scale(1); opacity: 1; }
    100% { transform: translateY(300px) rotate(720deg) scale(0); opacity: 0; }
}
@keyframes pr-confetti-sway {
    0%, 100% { margin-left: 0; }
    50%      { margin-left: 30px; }
}
.pr-confetti-container {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    pointer-events: none; z-index: 9999; overflow: hidden;
}
.pr-confetti-piece {
    position: absolute; top: -20px;
    width: 12px; height: 12px;
    animation: pr-confetti-fall 2.5s ease-in forwards;
}
.pr-confetti-piece:nth-child(odd)  { animation: pr-confetti-fall 2.5s ease-in forwards, pr-confetti-sway 1.5s ease-in-out infinite; }
.pr-confetti-piece:nth-child(even) { animation: pr-confetti-fall 2.8s ease-in forwards, pr-confetti-sway 2s ease-in-out infinite reverse; }

/* ── Shake (wrong answer) ────────────────────────────────────────────────── */
@keyframes pr-shake {
    0%, 100% { transform: translateX(0); }
    10%      { transform: translateX(-8px) rotate(-1deg); }
    20%      { transform: translateX(8px) rotate(1deg); }
    30%      { transform: translateX(-6px) rotate(-0.5deg); }
    40%      { transform: translateX(6px) rotate(0.5deg); }
    50%      { transform: translateX(-3px); }
    60%      { transform: translateX(3px); }
    70%      { transform: translateX(-1px); }
    80%      { transform: translateX(1px); }
}
.pr-card--shake {
    animation: pr-shake 0.6s ease-out;
}

/* ── Glow pulse (correct answer highlight) ───────────────────────────────── */
@keyframes pr-glow-pulse {
    0%   { box-shadow: 0 0 0 0 rgba(107,203,119,0.6); }
    70%  { box-shadow: 0 0 0 20px rgba(107,203,119,0); }
    100% { box-shadow: 0 0 0 0 rgba(107,203,119,0); }
}
.pr-card--glow {
    animation: pr-glow-pulse 0.8s ease-out;
}

/* ── Result icon entrance ────────────────────────────────────────────────── */
@keyframes pr-icon-pop {
    0%   { transform: scale(0) rotate(-45deg); }
    50%  { transform: scale(1.3) rotate(5deg); }
    70%  { transform: scale(0.9) rotate(-2deg); }
    100% { transform: scale(1) rotate(0deg); }
}
.pr-result-icon--pop {
    animation: pr-icon-pop 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

/* ── Grading scan effect ─────────────────────────────────────────────────── */
@keyframes pr-scan {
    0%   { top: -2px; opacity: 0; }
    20%  { opacity: 1; }
    80%  { opacity: 1; }
    100% { top: calc(100% + 2px); opacity: 0; }
}
.pr-scan-line {
    position: absolute; left: 0; width: 100%; height: 3px;
    background: linear-gradient(90deg, transparent, var(--pk-sky), transparent);
    animation: pr-scan 1.5s ease-in-out infinite;
    pointer-events: none; z-index: 10;
}
.pr-result--scanning {
    position: relative; overflow: hidden;
}

/* ── Card entrance (enhanced 3D) ─────────────────────────────────────────── */
@keyframes pr-card-enter {
    0%   { opacity: 0; transform: perspective(600px) rotateX(5deg) translateY(30px) scale(0.96); }
    100% { opacity: 1; transform: perspective(600px) rotateX(0) translateY(0) scale(1); }
}
.pr-card-entering {
    animation: pr-card-enter 0.5s cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ── Step highlight ripple ───────────────────────────────────────────────── */
.pr-step--animating .pr-step-num {
    animation: pr-step-pop 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}
@keyframes pr-step-pop {
    0%   { transform: scale(1); box-shadow: 0 0 0 0 rgba(255,107,107,0.5); }
    40%  { transform: scale(1.3); box-shadow: 0 0 0 8px rgba(255,107,107,0); }
    100% { transform: scale(1); box-shadow: 0 0 0 0 rgba(255,107,107,0); }
}

/* ── Progress bar glow ───────────────────────────────────────────────────── */
.pr-bar-fill {
    position: relative;
}
.pr-bar-fill::after {
    content: ''; position: absolute; right: 0; top: 50%; transform: translateY(-50%);
    width: 12px; height: 12px; border-radius: 50%;
    background: inherit; opacity: 0.8;
    box-shadow: 0 0 10px currentColor;
}
.pr-bar--pulse .pr-bar-fill::after {
    animation: pr-bar-pulse 0.8s ease-in-out infinite;
}
@keyframes pr-bar-pulse {
    0%, 100% { opacity: 0.6; transform: translateY(-50%) scale(1); }
    50%      { opacity: 1; transform: translateY(-50%) scale(1.6); }
}

/* ── Option select ripple ────────────────────────────────────────────────── */
@keyframes pr-ripple {
    0%   { transform: scale(0); opacity: 0.5; }
    100% { transform: scale(1.5); opacity: 0; }
}
.pr-option--selected::before {
    content: ''; position: absolute; top: 50%; left: 50%;
    width: 100%; height: 100%; border-radius: inherit;
    background: var(--pk-sky); opacity: 0;
    animation: pr-ripple 0.4s ease-out;
    pointer-events: none;
}
.pr-option {
    position: relative; overflow: hidden;
}

/* ── Question layout with navigator ─────────────────────────────────────── */
.pr-question-layout { display: flex; gap: 24px; align-items: flex-start; }
.pr-question-main { flex: 1; }
.pr-question-main .pr-card { flex: 1; display: flex; flex-direction: column; }
.pr-question-main { flex: 1; min-width: 0; }
.pr-navigator {
    flex: 0 0 200px; background: #fff; border-radius: 16px;
    padding: 20px; box-shadow: 0 2px 12px rgba(0,0,0,0.04);
    position: sticky; top: 80px;
}
.pr-nav-header { margin-bottom: 16px; }
.pr-nav-title { font-size: 14px; font-weight: 800; color: var(--pk-text-soft); }
.pr-nav-dots { display: grid; grid-template-columns: repeat(5, 1fr); gap: 8px; }
.pr-nav-dot {
    width: 32px; height: 32px; border-radius: 8px; border: 2px solid #eee;
    background: #fafafa; font-family: var(--pk-font); font-size: 12px;
    font-weight: 700; color: var(--pk-text-soft); cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    transition: all 0.2s;
}
.pr-nav-dot:hover { border-color: var(--pk-sky); }
.pr-nav-dot--ok { background: var(--pk-mint); color: #fff; border-color: var(--pk-mint); }
.pr-nav-dot--err { background: var(--pk-coral); color: #fff; border-color: var(--pk-coral); }
.pr-nav-dot--saved { background: var(--pk-sky); color: #fff; border-color: var(--pk-sky); }
.pr-nav-dot--current { border-color: var(--pk-sky); box-shadow: 0 0 0 3px rgba(77,150,255,0.25); transform: scale(1.1); }

/* ── Countdown timer ────────────────────────────────────────────────────── */
.pr-timer {
    display: flex; align-items: center; gap: 6px; margin-left: 16px;
    padding: 6px 14px; background: #fff; border-radius: var(--pk-radius-pill);
    border: 2px solid #eee; font-weight: 800; font-size: 15px;
}
.pr-timer-icon { font-size: 18px; }
.pr-timer-text { color: var(--pk-text); font-variant-numeric: tabular-nums; }
.pr-timer--warning { border-color: var(--pk-coral); background: #fff5f5; animation: pr-timer-pulse 1s ease-in-out infinite; }
.pr-timer--warning .pr-timer-text { color: var(--pk-coral); }
@keyframes pr-timer-pulse {
    0%, 100% { box-shadow: 0 0 0 0 rgba(255,107,107,0.4); }
    50%      { box-shadow: 0 0 0 6px rgba(255,107,107,0); }
}

/* ── Keyboard hint ──────────────────────────────────────────────────────── */
.pr-kbd-hint {
    display: flex; align-items: center; gap: 10px; margin-left: 12px;
    font-size: 11px; color: var(--pk-text-light); font-weight: 600;
}
.pr-kbd-hint span {
    padding: 2px 8px; background: #f0f0f0; border-radius: 4px;
    border: 1px solid #ddd; font-family: 'SF Mono', 'Fira Code', monospace;
}

/* ── Finish celebration ──────────────────────────────────────────────────── */
@keyframes pr-celebrate-in {
    0%   { opacity: 0; transform: scale(0.8); }
    60%  { opacity: 1; transform: scale(1.05); }
    100% { opacity: 1; transform: scale(1); }
}
.pr-finish--enter {
    animation: pr-celebrate-in 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}
@keyframes pr-score-count {
    from { opacity: 0; transform: translateY(20px); }
    to   { opacity: 1; transform: translateY(0); }
}
.pr-score span {
    display: inline-block; animation: pr-score-count 0.4s ease-out both;
}

/* ── Difficulty card entrance stagger ────────────────────────────────────── */
.pr-diff-card {
    animation: pr-card-enter 0.5s cubic-bezier(0.22, 0.61, 0.36, 1) both;
}
.pr-diff-grid--3cols .pr-diff-card:nth-child(1) { animation-delay: 0.05s; }
.pr-diff-grid--3cols .pr-diff-card:nth-child(2) { animation-delay: 0.10s; }
.pr-diff-grid--3cols .pr-diff-card:nth-child(3) { animation-delay: 0.15s; }
.pr-diff-grid--3cols .pr-diff-card:nth-child(4) { animation-delay: 0.20s; }
.pr-diff-grid--3cols .pr-diff-card:nth-child(5) { animation-delay: 0.25s; }

/* Step card entrance */
.pr-step-card {
    animation: pr-card-enter 0.35s cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* Extra message transition */
.pr-extra-msg { transition: all 0.3s ease; }

/* ── Summary card ────────────────────────────────────────────────────── */
.pr-summary-card {
    padding: 24px; border-radius: 16px;
    background: var(--pk-bg-warm); border: 2px solid var(--pk-border);
    text-align: center;
}
.pr-summary-grid {
    display: grid; grid-template-columns: repeat(auto-fit, minmax(120px,1fr));
    gap: 10px; text-align: center;
}
.pr-summary-item {
    padding: 12px 8px; border-radius: 10px; background: #fff;
    border: 1px solid #eee;
}
.pr-summary-item-num { font-size: 22px; font-weight: 900; color: var(--pk-text); }
.pr-summary-item-label { font-size: 12px; color: var(--pk-text-soft); margin-top: 2px; }

/* ── Navigator actions (timer + submit) ──────────────────────────────── */
.pr-nav-actions { margin-bottom: 8px; }
.pr-nav-actions .pr-timer { margin-left: 0; margin-bottom: 6px; width: 100%; box-sizing: border-box; justify-content: center; }
.pr-nav-header { margin-bottom: 12px; padding-bottom: 10px; border-bottom: 1px solid var(--pk-border); }

/* ── Navigator dots: stronger marking for answered ──────────────────── */
.pr-nav-dot--saved { background: var(--pk-sky); color: #fff; border-color: var(--pk-sky); position: relative; }
.pr-nav-dot--saved::after {
    content: ''; position: absolute; bottom: 2px; left: 50%; transform: translateX(-50%);
    width: 6px; height: 6px; border-radius: 50%; background: #fff;
}
.pr-nav-dot--ok { background: var(--pk-mint); color: #fff; border-color: var(--pk-mint); }
.pr-nav-dot--ok::after {
    content: '✓'; position: absolute; top: -4px; right: -4px;
    font-size: 9px; font-weight: 900; color: var(--pk-mint); background: #fff;
}
.pr-nav-dot--err { background: var(--pk-coral); color: #fff; border-color: var(--pk-coral); }
.pr-nav-dot--err::after {
    content: '✗'; position: absolute; top: -4px; right: -4px;
    font-size: 9px; font-weight: 900; color: var(--pk-coral); background: #fff;
}

/* ── Resume banner ───────────────────────────────────────────────────── */
.pr-resume-banner { margin-bottom: 20px; }
.pr-resume-banner-inner {
    display: flex; align-items: center; gap: 14px; flex-wrap: wrap;
    padding: 16px 20px; border-radius: 12px;
    background: linear-gradient(135deg, #fff8e1, #fff3e0);
    border: 2px solid #ffd54f; box-shadow: 0 2px 12px rgba(255, 152, 0, 0.12);
}
.pr-resume-icon { font-size: 28px; }
.pr-resume-text { flex: 1; min-width: 200px; font-size: 14px; color: var(--pk-text); font-weight: 600; }
.pr-resume-actions { display: flex; gap: 8px; }