:root {
    /* Tokyodark */
    --rosewater: #f5e0dc;
    --flamingo: #ee6d85;
    --pink: #d57eeb;
    --mauve: #a485dd;
    --red: #ee6d85;
    --maroon: #e06c75;
    --peach: #f6955b;
    --yellow: #d7a65f;
    --green: #95c561;
    --teal: #63cdcf;
    --sky: #63cdcf;
    --sapphire: #7199ee;
    --blue: #7199ee;
    --lavender: #bda0f0;
    --text: #a0a8cd;
    --subtext1: #8b94bd;
    --subtext0: #7680a3;
    --overlay2: #626a8a;
    --overlay1: #525a78;
    --overlay0: #424a66;
    --surface2: #2e2f45;
    --surface1: #232438;
    --surface0: #171824;
    --base: #11121d;
    --mantle: #0b0c14;
    --crust: #06070c;
}

[data-theme="light"] {
    /* Tokyo Night Light */
    --rosewater: #f5e0dc;
    --flamingo: #d63e6c;
    --pink: #b946a8;
    --mauve: #7847bd;
    --red: #c0302e;
    --maroon: #b4434e;
    --peach: #b15c00;
    --yellow: #8f6a18;
    --green: #4e7a2d;
    --teal: #118c8e;
    --sky: #118c8e;
    --sapphire: #3660c1;
    --blue: #3660c1;
    --lavender: #9266d0;
    --text: #1a1e33;
    --subtext1: #2e3450;
    --subtext0: #434968;
    --overlay2: #6a7194;
    --overlay1: #8189aa;
    --overlay0: #959dbd;
    --surface2: #c4c8dd;
    --surface1: #d8dbed;
    --surface0: #e4e7f4;
    --base: #d5d6db;
    --mantle: #e9eaf0;
    --crust: #f0f1f5;
}

[data-theme="light"] .search-box input {
    background: #fff;
    border-color: var(--surface2);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

[data-theme="light"] .search-box input:focus {
    border-color: var(--mauve);
    box-shadow: 0 0 0 3px rgba(120, 71, 189, 0.12);
}

[data-theme="light"] .settings-dropdown {
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
}

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

body {
    font-family: "DM Sans", sans-serif;
    background: var(--base);
    color: var(--text);
    height: 100vh;
    overflow: hidden;
    display: flex;
}

/* Theme transition — View Transition API, radial from top-right */
::view-transition-old(root),
::view-transition-new(root) {
    animation: none;
    mix-blend-mode: normal;
}

::view-transition-new(root) {
    clip-path: circle(0% at 100% 0%);
    animation: theme-reveal 1s cubic-bezier(0.25, 0.8, 0.25, 1) forwards;
}

@keyframes theme-reveal {
    to {
        clip-path: circle(150% at 100% 0%);
    }
}

.sidebar {
    width: 380px;
    min-width: 380px;
    height: 100vh;
    background: var(--mantle);
    border-right: 1px solid var(--surface0);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.sidebar-header {
    padding: 20px 24px 16px;
    border-bottom: 1px solid var(--surface0);
}

.logo-row {
    display: flex;
    align-items: center;
}

.sidebar-footer {
    padding: 14px 16px 16px;
    border-top: 1px solid var(--surface0);
    background: var(--mantle);
}

.logo-img {
    width: 56px;
    height: 56px;
    display: block;
    object-fit: contain;
    margin-right: 0px;
    image-rendering: pixelated;
    image-rendering: crisp-edges;
}

.logo-text {
    font-family: "Pixelify Sans", "DM Sans", sans-serif;
    font-size: 22px;
    font-weight: 600;
    letter-spacing: 0.5px;
    color: var(--text);
}

.beta-tag {
    font-family: "JetBrains Mono", monospace;
    font-size: 9px;
    font-weight: 600;
    letter-spacing: 0.8px;
    padding: 2px 6px;
    border-radius: 4px;
    background: var(--mauve);
    color: var(--crust);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 4px;
    margin-left: auto;
}

.header-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border: none;
    border-radius: 8px;
    background: transparent;
    color: var(--overlay2);
    cursor: pointer;
    transition: background 0.15s, color 0.15s;
    text-decoration: none;
}

.header-btn:hover {
    background: var(--surface1);
    color: var(--text);
}

.header-btn svg {
    width: 18px;
    height: 18px;
}

/* Settings wrapper for positioning dropdown */
.settings-wrapper {
    position: relative;
}

/* Cog spin */
#settingsBtn svg {
    transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

#settingsBtn.active svg {
    transform: rotate(120deg);
}

#settingsBtn.active {
    background: var(--surface1);
    color: var(--text);
}

/* Settings dropdown */
.settings-dropdown {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    width: 220px;
    background: var(--surface0);
    border: 1px solid var(--surface2);
    border-radius: 12px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
    opacity: 0;
    transform: translateY(-8px) scale(0.95);
    transform-origin: top right;
    pointer-events: none;
    transition: opacity 0.3s cubic-bezier(0.34, 1.56, 0.64, 1),
                transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
    z-index: 100;
}

.settings-dropdown.open {
    opacity: 1;
    transform: translateY(0) scale(1);
    pointer-events: auto;
}

.settings-dropdown-content {
    padding: 8px;
}

/* Settings menu item */
.settings-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 10px;
    border-radius: 8px;
}

.settings-item-label {
    font-size: 13px;
    font-weight: 500;
    color: var(--text);
}

/* Sun/Moon toggle switch */
.theme-toggle {
    background: none;
    border: none;
    padding: 0;
    cursor: pointer;
}

.theme-toggle-track {
    position: relative;
    width: 52px;
    height: 28px;
    background: var(--surface2);
    border-radius: 14px;
    transition: background 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 6px;
}

.theme-toggle-thumb {
    position: absolute;
    top: 3px;
    left: 3px;
    width: 22px;
    height: 22px;
    background: var(--mantle);
    border-radius: 50%;
    transition: transform 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
    z-index: 2;
}

.theme-toggle.active .theme-toggle-track {
    background: var(--yellow);
}

.theme-toggle.active .theme-toggle-thumb {
    transform: translateX(24px);
    background: #fff;
}

.theme-icon {
    width: 14px;
    height: 14px;
    position: relative;
    z-index: 1;
    transition: opacity 0.25s ease, transform 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.sun-icon {
    color: var(--overlay2);
    opacity: 0.5;
    transform: rotate(-30deg) scale(0.8);
}

.moon-icon {
    color: var(--overlay2);
    opacity: 1;
}

.theme-toggle.active .sun-icon {
    color: var(--mantle);
    opacity: 1;
    transform: rotate(0deg) scale(1);
}

.theme-toggle.active .moon-icon {
    opacity: 0;
    transform: rotate(30deg) scale(0.8);
}

.search-box {
    position: relative;
}

.search-box input {
    width: 100%;
    padding: 10px 14px 10px 38px;
    background: var(--surface0);
    border: 1px solid var(--surface1);
    border-radius: 8px;
    color: var(--text);
    font-family: "DM Sans", sans-serif;
    font-size: 13.5px;
    outline: none;
    transition: border-color 0.15s;
}

.search-box input::placeholder {
    color: var(--overlay0);
}

.search-box input:focus {
    border-color: var(--mauve);
}

.search-icon {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    width: 16px;
    height: 16px;
    color: var(--sapphire);
}

.search-submit {
    position: absolute;
    right: 6px;
    top: 50%;
    transform: translateY(-50%);
    background: var(--mauve);
    border: none;
    border-radius: 6px;
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background 0.15s;
}

.search-submit:hover {
    background: var(--lavender);
}

.search-submit svg {
    width: 14px;
    height: 14px;
    fill: var(--crust);
}

.steps-container {
    flex: 1;
    overflow-y: auto;
    padding: 8px;
    display: flex;
    flex-direction: column;
    position: relative;
    scrollbar-width: thin;
    scrollbar-color: var(--surface1) transparent;
}

.loading-topic {
    position: absolute;
    top: 8px;
    left: 8px;
    right: 8px;
    animation: topic-enter 0.9s cubic-bezier(0.2, 0.8, 0.2, 1);
}

@keyframes topic-enter {
    0% {
        opacity: 0;
        transform: translateY(-16px);
        color: var(--mauve);
    }
    40% {
        opacity: 1;
        color: var(--mauve);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
        color: var(--overlay0);
    }
}

@keyframes loading-enter {
    0% {
        opacity: 0;
        transform: translateY(12px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

.steps-list {
    width: 100%;
}

.steps-container::-webkit-scrollbar {
    width: 4px;
}
.steps-container::-webkit-scrollbar-track {
    background: transparent;
}
.steps-container::-webkit-scrollbar-thumb {
    background: var(--surface1);
    border-radius: 4px;
}

.empty-state {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 40px 24px;
}

.empty-icon {
    width: 44px;
    height: 44px;
    border-radius: 10px;
    background: var(--surface0);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 14px;
}

.empty-icon svg {
    width: 20px;
    height: 20px;
    color: var(--overlay0);
}

.error-state .empty-icon {
    background: transparent;
    border: 1px solid var(--flamingo);
}

.error-state .empty-icon svg {
    color: var(--flamingo);
}

.error-state h3 {
    color: var(--flamingo);
}

.error-state p {
    color: var(--maroon);
}

.empty-logo {
    width: 160px;
    margin-bottom: 18px;
    color: var(--mauve);
}

.empty-logo svg {
    width: 100%;
    height: auto;
}

.empty-state h3 {
    font-size: 14px;
    font-weight: 500;
    color: var(--subtext0);
    margin-bottom: 4px;
}

.empty-state p {
    font-size: 12.5px;
    color: var(--overlay0);
    line-height: 1.5;
    max-width: 220px;
}

.topic-label {
    padding: 10px 14px 6px;
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.8px;
    text-transform: uppercase;
    color: var(--overlay0);
}

.step-card {
    padding: 12px 14px;
    margin-bottom: 2px;
    border-radius: 8px;
    border-left: 2px solid transparent;
    cursor: pointer;
    transition:
        background 0.15s,
        border-color 0.15s;
    animation: step-drop 0.55s cubic-bezier(0.34, 1.56, 0.4, 1) backwards;
    animation-delay: calc(var(--step-index, 0) * 90ms + 180ms);
    transform-origin: top center;
}

@keyframes step-drop {
    0% {
        opacity: 0;
        transform: translateY(-22px) scale(0.96);
    }
    60% {
        opacity: 1;
        transform: translateY(3px) scale(1.02);
    }
    80% {
        transform: translateY(-1px) scale(0.995);
    }
    100% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.step-card:hover {
    background: var(--surface0);
}

.step-card.active {
    background: var(--surface0);
    border-left-color: var(--mauve);
}

.step-card.active .step-indicator {
    background: var(--mauve);
    color: var(--crust);
    border-color: var(--mauve);
}

.step-top {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 6px;
}

.step-indicator {
    width: 22px;
    height: 22px;
    border-radius: 5px;
    border: 1px solid var(--surface2);
    background: var(--surface0);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    font-weight: 600;
    font-family: "JetBrains Mono", monospace;
    color: var(--subtext0);
    flex-shrink: 0;
    transition: all 0.15s;
}

.step-timestamp {
    font-family: "JetBrains Mono", monospace;
    font-size: 11px;
    color: var(--overlay0);
    margin-left: auto;
}

.step-card.active .step-timestamp {
    color: var(--mauve);
}

.step-explanation {
    font-size: 13px;
    line-height: 1.5;
    color: var(--subtext0);
    padding-left: 32px;
}

.step-card.active .step-explanation {
    color: var(--text);
}

.loading-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px 24px;
    animation: loading-enter 0.8s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.loading-title {
    font-size: 14px;
    font-weight: 500;
    color: var(--subtext0);
    margin-top: 18px;
    margin-bottom: 4px;
}

.loading-subtitle {
    font-size: 12.5px;
    color: var(--overlay0);
    line-height: 1.5;
    max-width: 220px;
    text-align: center;
}

.loading-logo {
    width: 160px;
    color: var(--mauve);
}

.loading-logo svg {
    width: 100%;
    height: auto;
}

.loading-logo .dot {
    animation: dot-pulse 2.4s ease-in-out infinite;
}

.loading-logo .dot-1 {
    animation-delay: 0s;
}
.loading-logo .dot-2 {
    animation-delay: 0.4s;
}
.loading-logo .dot-3 {
    animation-delay: 0.8s;
}

@keyframes dot-pulse {
    0%,
    70%,
    100% {
        opacity: 0.15;
    }
    35% {
        opacity: 1;
    }
}

.loading-text {
    font-size: 13px;
    color: var(--overlay0);
}

.main-content {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--base);
    position: relative;
    overflow: hidden;
}

.video-wrapper {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 32px;
}

.video-wrapper video {
    max-width: 100%;
    max-height: 100%;
    border-radius: 8px;
    background: var(--crust);
    cursor: pointer;
}

.video-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 10px;
    color: var(--teal);
}

.video-placeholder svg {
    width: 48px;
    height: 48px;
    opacity: 0.45;
}

.video-placeholder span {
    font-size: 13px;
    color: var(--subtext0);
}

.progress-bar {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--surface0);
}

.progress-fill {
    height: 100%;
    background: var(--mauve);
    width: 0%;
    transition: width 0.3s linear;
}