<template>
  <section class="voice-conversation">
    <main class="voice-content">
      <header class="hero-title">
        <p>低延迟实时语音对讲</p>
      </header>

      <div class="voice-visual" :class="{ active: connectionStatus === 'connected' }">
        <div class="sound-wave sound-wave--left" aria-hidden="true">
          <i v-for="index in 7" :key="`left-${index}`"></i>
        </div>

        <div class="microphone-orbit">
          <div class="orbit-glow"></div>
          <div class="microphone-core">
            <svg viewBox="0 0 48 48" aria-label="麦克风" role="img">
              <path d="M24 30a8 8 0 0 0 8-8V12a8 8 0 0 0-16 0v10a8 8 0 0 0 8 8Z" />
              <path d="M11 21v2a13 13 0 0 0 26 0v-2M24 36v8M17 44h14" />
            </svg>
          </div>
        </div>

        <div class="sound-wave sound-wave--right" aria-hidden="true">
          <i v-for="index in 7" :key="`right-${index}`"></i>
        </div>
      </div>

      <div class="floating-status">
        <span :class="['status-light', connectionStatus]"></span>
        {{ statusMeta.label }}
      </div>

      <div class="call-controls">
        <el-button
          v-if="!isCalling"
          class="call-button"
          :loading="isStarting"
          @click="startCall"
        >
          开始通话
        </el-button>
        <el-button v-else class="call-button call-button--danger" @click="endCall">
          结束通话
        </el-button>
        <el-button
          v-if="isCalling"
          class="mute-button"
          round
          @click="toggleMute"
        >
          {{ isMuted ? '取消静音' : '静音' }}
        </el-button>
      </div>

      <section class="status-card">
        <div class="status-copy">
          <p>当前状态：<strong>{{ statusMeta.label }}</strong></p>
          <span>{{ statusMeta.description }}</span>
        </div>
        
        <div class="feature-tags">
          <span>高清语音</span>
          <span>低延迟</span>
          <span>加密传输</span>
        </div>
      </section>
    </main>
    <!-- PCM 播放由 AudioWorklet 连续输出，不需要额外 audio 元素。 -->
  </section>
</template>

<script setup>
import { computed, onBeforeUnmount, ref } from 'vue'
import { ElMessage, ElNotification } from 'element-plus'
import { useRobotStore } from '@/stores/robot'

// 机器人实际音频流为 48kHz，因此浏览器上传也统一为 48kHz。
const TARGET_SAMPLE_RATE = 48000
const TARGET_CHANNELS = 2
const JOIN_TIMEOUT = 10000
const robotStore = useRobotStore()

// 页面交互状态。
const isCalling = ref(false)
const isStarting = ref(false)
const isMuted = ref(false)
const connectionStatus = ref('idle')
const errorMessage = ref('')

// 本次通话占用的浏览器资源。
const localStream = ref(null)
const webSocket = ref(null)
let audioContext
let mediaStreamSource
let captureNode
let silentGain
let nextPlaybackTime = 0
let resampleFraction = 0
let remoteSampleRate = TARGET_SAMPLE_RATE
let remoteChannels = 1
let callSessionId = 0

const statusMeta = computed(() => {
  const statusMap = {
    idle: { label: '未连接', description: '点击按钮建立语音通道' },
    connecting: { label: '连接中', description: '正在建立音频通道，请稍候' },
    connected: { label: '通话中', description: 'PCM 音频通道已建立，可以开始对讲' },
    error: { label: '未连接', description: '连接出现异常，请检查后重试' }
  }
  return statusMap[connectionStatus.value] || statusMap.idle
})

/**
 * 统一显示通话异常。
 * @param {string} message 用户可读的错误说明
 * @param {Error} [error] 原始异常
 */
function showError(message, error) {
  console.error(message, error)
  errorMessage.value = message
  connectionStatus.value = 'error'
  ElNotification.error({ title: '语音通话异常', message })
}

/**
 * 发送 WebSocket 控制消息。
 * 此方法只允许发送 JSON；PCM 音频由 sendPcmFrame 单独以二进制发送。
 * @param {Object} message 控制消息
 */
function sendControlMessage(message) {
  if (webSocket.value?.readyState === WebSocket.OPEN) {
    webSocket.value.send(JSON.stringify(message))
  }
}

/**
 * 将 Float32 PCM 转换成明确的小端 Int16 PCM。
 * 使用 DataView 的 littleEndian=true，避免依赖运行平台的原生字节序。
 * @param {Float32Array} float32 取值范围为 -1 到 1 的 PCM
 * @returns {ArrayBuffer} PCM_S16LE 数据
 */
function floatToInt16Pcm(float32, channels = 1) {
  const buffer = new ArrayBuffer(float32.length * channels * 2)
  const view = new DataView(buffer)
  for (let index = 0; index < float32.length; index += 1) {
    const sample = Math.max(-1, Math.min(1, float32[index]))
    const int16 = sample < 0 ? sample * 0x8000 : sample * 0x7fff
    // 单声道麦克风复制到左右声道，生成交错 S16LE：L0,R0,L1,R1...
    for (let channel = 0; channel < channels; channel += 1) {
      view.setInt16((index * channels + channel) * 2, int16, true)
    }
  }
  return buffer
}

/**
 * 将后端返回的小端 Int16 PCM 转成 AudioWorklet 使用的 Float32 PCM。
 * @param {ArrayBuffer} buffer 一帧 960 字节 PCM_S16LE
 * @returns {Float32Array} 480 个浮点采样
 */
function int16ToFloat32(buffer) {
  const view = new DataView(buffer)
  const result = new Float32Array(Math.floor(buffer.byteLength / 2))
  for (let index = 0; index < result.length; index += 1) {
    const value = view.getInt16(index * 2, true)
    result[index] = value < 0 ? value / 0x8000 : value / 0x7fff
  }
  return result
}

/** 当浏览器实际采样率不是 48kHz 时，通过线性插值转换为机器人采样率。 */
function resample(input, fromRate, toRate) {
  if (fromRate === toRate) return new Float32Array(input)
  // 保留每个回调产生的小数样本，避免逐块四舍五入造成长期采样率漂移。
  const exactLength = input.length * toRate / fromRate + resampleFraction
  const outputLength = Math.max(1, Math.floor(exactLength))
  resampleFraction = exactLength - outputLength
  const output = new Float32Array(outputLength)
  const ratio = fromRate / toRate
  for (let index = 0; index < outputLength; index += 1) {
    const position = index * ratio
    const left = Math.floor(position)
    const right = Math.min(left + 1, input.length - 1)
    const fraction = position - left
    output[index] = input[left] * (1 - fraction) + input[right] * fraction
  }
  return output
}

/**
 * 发送一帧浏览器麦克风 PCM。
 * 每次只发送 480 samples，即 10ms、960 bytes。
 * @param {Float32Array} samples AudioWorklet 采集的一帧数据
 */
function sendPcmFrame(samples) {
  const socket = webSocket.value
  if (isMuted.value || socket?.readyState !== WebSocket.OPEN) return
  socket.send(floatToInt16Pcm(
    resample(samples, audioContext.sampleRate, TARGET_SAMPLE_RATE),
    TARGET_CHANNELS
  ))
}

/**
 * 将机器人返回的二进制数据按 960 字节切帧后加入播放队列。
 * 支持后端将半帧或多帧放在一个 WebSocket 消息中的情况。
 * @param {ArrayBuffer} buffer WebSocket 二进制数据
 */
function enqueueIncomingPcm(buffer) {
  if (!audioContext || audioContext.state === 'closed' || buffer.byteLength < 2) return
  const interleavedSamples = int16ToFloat32(buffer)
  const frameCount = Math.floor(interleavedSamples.length / remoteChannels)
  if (!frameCount) return
  // 机器人返回交错 PCM；按声道拆分后再交给 AudioBuffer 播放。
  const audioBuffer = audioContext.createBuffer(remoteChannels, frameCount, remoteSampleRate)
  for (let channel = 0; channel < remoteChannels; channel += 1) {
    const channelData = audioBuffer.getChannelData(channel)
    for (let frame = 0; frame < frameCount; frame += 1) {
      channelData[frame] = interleavedSamples[frame * remoteChannels + channel]
    }
  }
  const source = audioContext.createBufferSource()
  source.buffer = audioBuffer
  source.connect(audioContext.destination)
  const now = audioContext.currentTime
  if (nextPlaybackTime < now || nextPlaybackTime > now + 1) nextPlaybackTime = now + 0.03
  source.start(nextPlaybackTime)
  nextPlaybackTime += audioBuffer.duration
}

/**
 * 处理后端文本控制消息。
 * @param {Object} message 已解析的 JSON 消息
 * @param {number} sessionToken 前端本地会话编号
 */
function handleControlMessage(message, sessionToken) {
  if (sessionToken !== callSessionId) return
  if (message.type === 'audio-format') {
    const sampleRate = Number(message.sampleRate)
    const channels = Number(message.channels)
    if (sampleRate >= 8000 && sampleRate <= 192000) remoteSampleRate = sampleRate
    if (Number.isInteger(channels) && channels >= 1 && channels <= 8) remoteChannels = channels
  } else if (message.type === 'error' || message.type === 'remote-ended') {
    showError(message.message || '机器人已结束音频流')
    cleanupResources(false)
  }
}

/**
 * 连接音频 WebSocket，发送 join 并等待后端返回 joined。
 * 文本帧作为控制 JSON 处理，二进制帧作为机器人 PCM 处理。
 * @param {number} sessionToken 前端本地会话编号
 * @returns {Promise<Object>} joined 消息
 */
function connectAudioServer(sessionToken) {
  return new Promise((resolve, reject) => {
    const protocol = location.protocol === 'https:' ? 'wss:' : 'ws:'
    const devHost = `${location.hostname}:${import.meta.env.VITE_SERVICE_PORT || 3000}`
    const url = import.meta.env.VITE_AUDIO_SERVER_URL
      || `${protocol}//${import.meta.env.DEV ? devHost : location.host}/audio`
    const socket = new WebSocket(url)
    socket.binaryType = 'arraybuffer'
    webSocket.value = socket

    const timeout = window.setTimeout(() => reject(new Error('连接音频服务超时')), JOIN_TIMEOUT)
    socket.onopen = () => sendControlMessage({
      type: 'init',
      microphoneId: robotStore.micDeviceId,
      speakerId: robotStore.spkDeviceId,
      robotAddress: robotStore.ip
    })
    socket.onmessage = (event) => {
      if (typeof event.data !== 'string') {
        enqueueIncomingPcm(event.data)
        return
      }
      try {
        const message = JSON.parse(event.data)
        if (message.type === 'ready') {
          window.clearTimeout(timeout)
          resolve(message)
        } else if (message.type === 'connection-failed') {
          window.clearTimeout(timeout)
          reject(new Error(message.message || '机器人音频服务连接失败'))
        } else {
          handleControlMessage(message, sessionToken)
        }
      } catch (error) {
        reject(new Error('音频服务返回了无效消息', { cause: error }))
      }
    }
    socket.onerror = () => reject(new Error('无法连接音频 WebSocket 服务'))
    socket.onclose = () => {
      window.clearTimeout(timeout)
      if (sessionToken === callSessionId && isCalling.value) {
        showError('音频连接已断开')
        cleanupResources(false)
      }
    }
  })
}

/**
 * 创建浏览器 AudioContext 和麦克风采集节点。
 * 麦克风只进入静音采集支路，不会在本地直接回放。
 * @param {MediaStream} stream 麦克风媒体流
 */
async function setupAudioPipeline(stream) {
  await audioContext.resume()
  mediaStreamSource = audioContext.createMediaStreamSource(stream)
  // ScriptProcessor 兼容旧浏览器；回调中根据 audioContext.sampleRate 手动重采样。
  captureNode = audioContext.createScriptProcessor(2048, 1, 1)
  silentGain = audioContext.createGain()
  silentGain.gain.value = 0
  captureNode.onaudioprocess = (event) => sendPcmFrame(event.inputBuffer.getChannelData(0))
  mediaStreamSource.connect(captureNode)
  captureNode.connect(silentGain)
  silentGain.connect(audioContext.destination)
}

/**
 * 开始实时语音通话。
 * 流程：连接 WS → join/joined → 获取麦克风 → 启动 AudioWorklet → 二进制 PCM 双向传输。
 */
async function startCall() {
  if (isStarting.value || isCalling.value) return
  isStarting.value = true
  connectionStatus.value = 'connecting'
  errorMessage.value = ''
  const sessionToken = ++callSessionId
  try {
    if (!robotStore.ip || !robotStore.micDeviceId || !robotStore.spkDeviceId) {
      throw new Error('请先配置机器人地址、麦克风 ID 和扬声器 ID')
    }
    // 必须在按钮点击的用户手势中创建，以符合浏览器自动播放策略。
    audioContext = new AudioContext({ latencyHint: 'interactive' })
    await connectAudioServer(sessionToken)
    if (sessionToken !== callSessionId) return
    const stream = await navigator.mediaDevices.getUserMedia({
      audio: {
        channelCount: 1,
        echoCancellation: true,
        noiseSuppression: true,
        autoGainControl: true
      }
    })
    localStream.value = stream
    await setupAudioPipeline(stream)
    isCalling.value = true
    connectionStatus.value = 'connected'
    ElMessage.success('语音通话已建立')
  } catch (error) {
    cleanupResources(false)
    showError(error.message || '无法开始语音通话', error)
  } finally {
    isStarting.value = false
  }
}

/**
 * 切换麦克风静音状态。
 * 禁用媒体轨道后 Worklet 收到静音采样，不会发送真实麦克风声音。
 */
function toggleMute() {
  const audioTracks = localStream.value?.getAudioTracks() || []
  if (!audioTracks.length) return

  isMuted.value = !isMuted.value
  audioTracks.forEach((track) => {
    track.enabled = !isMuted.value
  })
  ElMessage.info(isMuted.value ? '麦克风已静音' : '麦克风已取消静音')
}

/**
 * 释放 WebSocket、麦克风和 Web Audio 资源。
 * @param {boolean} notifyBackend 是否在关闭前发送 stop 控制消息
 */
function cleanupResources(notifyBackend = true) {
  callSessionId += 1
  if (notifyBackend) sendControlMessage({ type: 'stop' })
  const socket = webSocket.value
  webSocket.value = null
  if (socket && socket.readyState < WebSocket.CLOSING) socket.close(1000, 'call ended')
  localStream.value?.getTracks().forEach((track) => track.stop())
  localStream.value = null
  captureNode?.disconnect()
  mediaStreamSource?.disconnect()
  silentGain?.disconnect()
  captureNode = undefined
  mediaStreamSource = undefined
  silentGain = undefined
  if (audioContext && audioContext.state !== 'closed') audioContext.close()
  audioContext = undefined
  nextPlaybackTime = 0
  resampleFraction = 0
  remoteSampleRate = TARGET_SAMPLE_RATE
  remoteChannels = 1
  isCalling.value = false
  isMuted.value = false
}

/**
 * 主动结束当前通话。
 */
function endCall() {
  cleanupResources()
  connectionStatus.value = 'idle'
  errorMessage.value = ''
  ElMessage.success('通话已结束')
}

// 离开页面时释放麦克风、AudioWorklet 和 WebSocket。
onBeforeUnmount(cleanupResources)
</script>

<style lang="scss" scoped>
$cyan: #46c8ff;
$blue: #2478ff;
$purple: #936cff;
$panel-border: rgb(112 192 255 / 24%);

.voice-conversation {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 400px;
  max-height: 400px;
  min-height: 0;
  padding: 30px 28px 16px;
  overflow: hidden;
  box-sizing: border-box;
  color: #fff;
  background:
    radial-gradient(circle at 50% 38%, rgb(44 90 198 / 34%) 0%, transparent 33%),
    radial-gradient(circle at 75% 20%, rgb(81 49 172 / 18%) 0%, transparent 30%),
    linear-gradient(145deg, #071a3e 0%, #08152f 45%, #050c21 100%);

  &::before,
  &::after {
    position: absolute;
    content: '';
    pointer-events: none;
  }

  &::before {
    inset: 0;
    background: linear-gradient(90deg, rgb(32 143 255 / 7%) 1px, transparent 1px),
      linear-gradient(rgb(32 143 255 / 7%) 1px, transparent 1px);
    background-size: 42px 42px;
    mask-image: radial-gradient(circle at center, #000 12%, transparent 82%);
  }

  &::after {
    width: 360px;
    height: 360px;
    border: 1px solid rgb(70 200 255 / 7%);
    border-radius: 50%;
    box-shadow: 0 0 100px rgb(36 120 255 / 8%);
  }

  .tech-grid {
    position: absolute;
    inset: 0;
    background: repeating-linear-gradient(135deg, transparent 0 118px, rgb(89 138 255 / 3%) 119px 120px);
    pointer-events: none;
  }

  .corner-title {
    position: absolute;
    top: 16px;
    left: 22px;
    z-index: 2;
    font-size: 20px;
    font-weight: 700;
    letter-spacing: 1px;
    text-shadow: 0 0 18px rgb(74 168 255 / 30%);
  }

  .voice-content {
    position: relative;
    z-index: 2;
    display: flex;
    flex-direction: column;
    align-items: center;
    width: min(100%, 660px);
  }

  .hero-title {
    text-align: center;

    h1 {
      margin: 0;
      font-size: clamp(23px, 3vw, 30px);
      line-height: 1.2;
      letter-spacing: 5px;
      text-shadow: 0 0 25px rgb(79 159 255 / 25%);
    }

    p {
      margin: 4px 0 0;
      color: #86c6f4;
      font-size: 12px;
      letter-spacing: 3px;
    }
  }

  .voice-visual {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: clamp(18px, 4vw, 42px);
    width: 100%;
    margin-top: 13px;

    &.active {
      .microphone-orbit { animation: orbit-breathe 2.4s ease-in-out infinite; }
      .sound-wave i { animation-play-state: running; }
    }
  }

  .microphone-orbit {
    position: relative;
    display: grid;
    place-items: center;
    flex: 0 0 auto;
    width: 100px;
    height: 100px;
    border: 1px solid rgb(117 210 255 / 45%);
    border-radius: 50%;
    background: linear-gradient(145deg, rgb(41 146 255 / 20%), rgb(120 73 255 / 16%));
    box-shadow: 0 0 26px rgb(35 158 255 / 35%), inset 0 0 28px rgb(117 83 255 / 24%);

    &::before {
      position: absolute;
      inset: 7px;
      border: 1px solid rgb(160 124 255 / 55%);
      border-radius: inherit;
      box-shadow: inset 0 0 16px rgb(55 186 255 / 22%);
      content: '';
    }

    .orbit-glow {
      position: absolute;
      inset: -13px;
      border-radius: inherit;
      background: conic-gradient(from 90deg, transparent, rgb(58 190 255 / 35%), transparent, rgb(146 94 255 / 42%), transparent);
      filter: blur(12px);
    }
  }

  .microphone-core {
    position: relative;
    display: grid;
    place-items: center;
    width: 62px;
    height: 62px;
    border-radius: 50%;
    background: linear-gradient(145deg, #237bfa, #794be1);
    box-shadow: 0 8px 30px rgb(34 111 255 / 48%), inset 0 1px 1px rgb(255 255 255 / 35%);

    svg {
      width: 31px;
      height: 31px;
      overflow: visible;
      fill: #fff;
      stroke: #fff;
      stroke-width: 3;
      stroke-linecap: round;
      stroke-linejoin: round;

      path:first-child { stroke: none; }
      path:last-child { fill: none; }
    }
  }

  .sound-wave {
    display: flex;
    align-items: center;
    gap: 6px;
    width: 86px;
    height: 60px;

    i {
      width: 4px;
      height: var(--wave-height, 30px);
      border-radius: 10px;
      background: linear-gradient(to bottom, $cyan, $purple);
      box-shadow: 0 0 10px rgb(72 190 255 / 46%);
      opacity: 0.74;
      animation: wave-pulse 1.15s ease-in-out infinite alternate;
      animation-delay: calc(var(--index) * -0.09s);
      animation-play-state: paused;

      &:nth-child(1), &:nth-child(7) { --wave-height: 12px; --index: 1; opacity: 0.32; }
      &:nth-child(2), &:nth-child(6) { --wave-height: 22px; --index: 2; opacity: 0.48; }
      &:nth-child(3), &:nth-child(5) { --wave-height: 35px; --index: 3; opacity: 0.62; }
      &:nth-child(4) { --wave-height: 48px; --index: 4; }
    }

    &--left { justify-content: flex-end; }
    &--right { justify-content: flex-start; }
  }

  .floating-status {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-top: 7px;
    padding: 4px 13px;
    border: 1px solid rgb(255 255 255 / 9%);
    border-radius: 20px;
    color: #d5d9e4;
    background: rgb(31 38 58 / 86%);
    box-shadow: 0 7px 18px rgb(0 0 0 / 24%);
    font-size: 11px;

    .status-light {
      width: 7px;
      height: 7px;
      border-radius: 50%;
      background: #8791a7;

      &.connecting { background: #ffd166; box-shadow: 0 0 8px #ffd166; }
      &.connected { background: #4ef5ae; box-shadow: 0 0 8px #4ef5ae; }
      &.error { background: #ff6482; box-shadow: 0 0 8px #ff6482; }
    }
  }

  .call-controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    min-height: 34px;
    margin-top: 9px;

    :deep(.el-button + .el-button) { margin-left: 0; }
  }

  :deep(.call-button) {
    width: 178px;
    height: 34px;
    border: 1px solid rgb(125 207 255 / 52%);
    border-radius: 10px;
    color: #fff;
    background: linear-gradient(100deg, #176ee9, #448eff 56%, #7657e9);
    box-shadow: 0 10px 28px rgb(24 105 235 / 35%), inset 0 1px rgb(255 255 255 / 18%);
    font-size: 13px;
    font-weight: 700;
    letter-spacing: 2px;

    &:hover,
    &:focus {
      color: #fff;
      border-color: #86d5ff;
      background: linear-gradient(100deg, #2280ff, #54a0ff 56%, #896afa);
      transform: translateY(-1px);
    }

    &.call-button--danger {
      border-color: rgb(255 126 157 / 55%);
      background: linear-gradient(100deg, #cf3e67, #e4597e, #8554d9);
    }
  }

  :deep(.mute-button) {
    height: 30px;
    border-color: $panel-border;
    color: #badeff;
    background: rgb(16 45 85 / 72%);

    &:hover { color: #fff; border-color: $cyan; background: rgb(23 76 128 / 82%); }
  }

  .status-card {
    width: min(100%, 550px);
    margin-top: 20px;
    padding: 8px 18px 8px;
    border: 1px solid $panel-border;
    border-radius: 16px;
    box-sizing: border-box;
    background: linear-gradient(135deg, rgb(14 49 91 / 67%), rgb(20 30 74 / 55%));
    box-shadow: 0 16px 40px rgb(0 4 24 / 28%), inset 0 1px rgb(255 255 255 / 5%);
    backdrop-filter: blur(16px);

    .status-copy {
      text-align: center;

      p {
        margin: 0;
        color: #edf7ff;
        font-size: 12px;

        strong { color: #fff; font-weight: 600; }
      }

      span {
        display: block;
        margin-top: 2px;
        color: #8eafd0;
        font-size: 10px;
      }
    }

    .error-alert { margin-top: 6px; }
  }

  .feature-tags {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 9px;
    margin-top: 6px;
    padding-top: 6px;
    border-top: 1px solid rgb(116 186 255 / 13%);

    span {
      padding: 2px 8px;
      border: 1px solid rgb(87 183 255 / 35%);
      border-radius: 20px;
      color: #a9d6f8;
      background: rgb(31 104 166 / 13%);
      text-align: center;
      font-size: 10px;
    }
  }

  audio { display: none; }
}

@keyframes orbit-breathe {
  0%, 100% { transform: scale(1); filter: brightness(1); }
  50% { transform: scale(1.035); filter: brightness(1.16); }
}

@keyframes wave-pulse {
  from { transform: scaleY(0.58); opacity: 0.42; }
  to { transform: scaleY(1.08); opacity: 0.9; }
}

@media (max-width: 680px) {
  .voice-conversation {
    height: 400px;
    max-height: 400px;
    min-height: 0;
    padding: 38px 14px 12px;

    .corner-title { top: 12px; left: 16px; font-size: 17px; }
    .voice-visual { gap: 10px; }
    .microphone-orbit { width: 90px; height: 90px; }
    .microphone-core { width: 56px; height: 56px; }
    .microphone-core svg { width: 28px; height: 28px; }
    .sound-wave { width: 58px; gap: 4px; }
    .sound-wave i { width: 3px; }
    .call-controls { flex-wrap: wrap; }
  }
}

@media (max-width: 420px) {
  .voice-conversation {
    .hero-title p { letter-spacing: 1px; }
    .voice-visual { gap: 7px; }
    .sound-wave { width: 48px; gap: 3px; }
    .sound-wave i:nth-child(1),
    .sound-wave i:nth-child(7) { display: none; }
    .feature-tags { gap: 7px; }
    .status-card { padding-inline: 15px; }
  }
}
</style>
